Need Help, Car Wont Start, I've Gone Through Both Checklists

imp

Mustang Master
Jul 13, 2017
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I do have a timing light. It's set to 9*. It was at 13* and the car behaved the same.

My Harmonic Balancer wobbles pretty good. I'm wondering if I could spun it, could that have caused the car to go into a limp mode type state and die? If I spun it, maybe it's not truly at 9*?

I don't know anything about HB or how they work...
@93silverlx50
The Harmonic Balancer is made in two pieces, joined together by a thin "sleeve" of rubber. The rubber is "bonded" under heat and pressure, similar to the way the rubber lip element of an oil seal is bonded to the outer metal channel which supports the rubber part.

Occasionally, the bond breaks on a balancer, allowing the outer ring which has the timing marks on it to rotate a bit with relation to the inner hub. Thus the indicated timing is "off" by whatever amount of "slip" has occurred between the two parts. It might be only a degree or two, or a lot, disrupting engine performance greatly. The two parts rarely are known to come completely apart; I've never seen that happen.

Only way to positively check the timing mark location is to use a dial indicator mounted in such a way that it contacts the piston in Cylinder #1, up real close to Top Center, then rotate the crank back and forth about Top Center until the indicator remains stationary for the very smallest amount of rotation. Any other "eyeball" method, like a screwdriver stuck down against the piston top can be off 20 degrees, easily.

In a 5.0 having rod length = 5.09", at 10 degrees BTDC, the piston is down from Top Center only 0.0077", that's 4 human hairs thicknesses. At 1 degree BTDC, it is down only 0.00077", 700 millionths of an inch! Obviously, neither movement of the piston can be seen by the screwdriver method, eyeballing it. imp
 
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jrichker

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If the balancer wobbles, it does not provide an accurate timing reference. On top of that it no longer functions to help balance the engine, which can result in serious engine damage. Replace it before doing anything else.


Timing cover/harmonic balancer removal and replacement
The first steps are the same as replacing a water pump, but for reference I will include them too.

The first steps are the same as replacing a water pump, but for reference I will include them too.
You will notice the phrase “ in a zip bag or your loose parts bin” gets lots of repetition. This is an important concept to embrace, especially if the project stretches out more than a day or two. Some of us are neat and organized and work that way. Congratulations go out to you, because most of the hobbyist mechanics are not members of that elite group. You will need a box of sturdy quart size zip bags and a Sharpie marker to label them with along with the normal range of sockets and wrenches used in auto repair.
Time to complete this job will be 10-12 hours, maybe less if you are fast and don’t stop to take breaks.

Water pump removal
1.) Disconnect the battery negative terminal and cover the battery with heavy cardboard or at least 2 shop towels. You’ll thank me for this suggestion about the time you lay a long wrench or screwdriver over on top of the battery.

2.) Drain the radiator; most radiators have a drain valve or drain plug on the lower passenger side of the radiator. In most cases you either have to have really long skinny arms or have to jack the car up to get to it.
Plan B is a little simpler, but it involves more equipment: an air compressor, some air hose, a blowgun with a long skinny nozzle, and 6 ft. of scrap garden hose. A small diameter garden hose works better than large hose because you have to thread it through the radiator filler opening and past the transmission cooler. Cut a small hole just big enough to stick the blow gun nozzle in the garden hose about 6”-12” from the end, Stick the other end of the garden hose in the radiator as far down as you can get it. Stick the free end of the hose in your bucket or whatever container you are going to use. You’ll need to be able to capture about 1 ½ - 2 gallons of coolant. Stick the blowgun in the cut you made in the hose and give it a squeeze. If you are careful, it will start to siphon all of the coolant out the radiator and not spray coolant everywhere.

3.) Now comes the messy part; crawl under the car and remove the lower radiator hose clamp, radiator hose and then the radiator. Plan on spilling some coolant and getting wet in the process. I have done it 3 times over the last year and have always got a bath in coolant and a big spill to rinse down when I finished.

4.) Disconnect the upper radiator hose and the auto transmission cooler lines if this is an auto transmission car; be sure to cap the transmission cooler lines on the radiator and the lines to keep dirt and trash out of them.

5.) Remove the two10MM hex head radiator hold down bolts and brackets and put them in your parts bucket.

If this the first time you have done this job, put each set of fasters or small parts in individual zip bags and mark the bag with a description of where they came from with a sharpie marker. About the time you go to putting it back together, you’ll be glad that you took the time to do this. This is a good habit to develop if your project looks like it will stretch out longer than a day or two.

6.) Remove the fan shroud bolts that secure the fan shroud to the radiator and put them in you parts storage container or zip bag. Lift the radiator shroud clear of the slip clips that hold it to the bottom of the radiator and move it as far back away from the radiator as possible. Trim a large piece of cardboard to the width of the radiator and about 6” taller than the radiator. Now slide the cardboard down between the radiator and the fan shroud and lift the radiator out. You have prevented dinging the radiator or poking holes in it with this simple step. Save the cardboard, you will use it again when you put the radiator back in the car. Remove the radiator shroud and put it in a safe place along with the radiator. Watch out for the coolant in the overflow tank; a pan or jug needs to be handy to drain the coolant stored in it.

7.) Serpentine belt; if you have anything other than the stock arrangement, take a picture of how it fits around the pulleys BEFORE doing anything else.
Use a 17 MM socket and a long breaker bar to lift the belt tensioner off the serpentine belt. Remove the belt from the pulleys and check it over for frayed places or cracks; replace it now while you have it off and in hand. This is especially true if you have a non- stock belt arrangement.

8.) Use a 7/16” flat ratchet or gearwrench to remove the 4 bolts that hold the fan on the water pump. Remove the nuts from the 3 studs on the water pump, and the 2 power steering mount bolts and the 3 bolts that secure the A/C compressor (if present) to the A/C & PS mount plate. Loosen one bolt on the rear of the lower A/C mount; this will require a long extension and maybe universal joint socket. Put the bolt and the nuts in a zip bag or your loose parts bin.

9.) Remove the lower radiator hose from the water pump and put both hose clamps in a zip bag or loose parts bin.
Take a cardboard box, and turn it upside down. Count the number of bolts that hold the water pump on, don’t forget to count the 4 funny looking studs. Poke a hole in the box for each bolt/stud. Arrange the holes in a circular formation, and mark the box at the 12:00 point. When you remove a water pump bolt, put it in one of the holes in the box according to where it came out of the water pump. When you are done, all bolts will be arranged it the exact same order and position that you removed them from the water pump. That makes re-installing them easy, no wondering where does this bolt go. Put the cardboard with the bolts in it out of the way with the rest of the larger parts.

10.) Loosen the 4 hose clamps on the water pump heater and thermostat bypass hoses. Pull the water pump down and remove the hoses from the water pump and from the engine mounted plumbing that that they connect to. Set the water pump aside with the rest of the large parts.
Take note that the upper thermostat bypass hose goes to the thermostat housing and the lower hose goes to the heater return feed tubing. Put the hoses and hose clamps in a zip bag or your loose parts bin.

This is the end of the water pump removal section.

11.) Now that the water pump is out of the way, remove the harmonic balancer pulley – there are 4 bolts that need to come out. Take note that the bolts are grade 8 and have 6 radial marks stamped on their heads. Don’t lose them and don’t replace them with any bolt of lesser grade.
You’ll need a very long breaker bar and a 15/16” socket and a short extension for the harmonic balancer mount bolt. The breaker bar and socket need to be ½” drive because you will probably need a cheater bar on the breaker bar to get the harmonic balancer bolt loose. If your car is a 5 speed, put it in 5th gear and set the parking brake so that the harmonic balancer doesn’t turn when you try to loosen the bolt. If your car has an auto trans, a chain wrench like those used to remove oil filters may do the trick. Apply it to the harmonic balancer ribs that protrude from the rear of the balancer. A long pipe wrench may also be applied to the same ribs to prevent the engine from turning. A harmonic balancer puller is needed to remove the balancer. If you don’t own one, the auto parts store will loan or rent one to you. Remove the harmonic balancer bolt and washer then put the bolt back in and turn it 4-5 turns back into the crankshaft. The harmonic balancer puller needs to push on the bolt and not on the crankshaft threads. Thread the harmonic balancer puller mount bolts into the holes for the pulley mount until they bottom out; make sure that the bolts are about the same length and not obviously too long or too short. Crank away on the harmonic balancer puller center bolt until the puller hits the balancer mount bolt. You’ll notice a sudden increase in effort to turn the puller center bolt. Remove the puller and then remove the balancer mount bolt. In most cases, the balancer can now be removed by hand and will slide off the crankshaft with a little effort. If not, several washers placed inside the balancer hub and resting upon the end of the crankshaft will do the job. The object is to give the harmonic balancer puller center bolt something to push on and not damage the crankshaft internal threads. At some point, the harmonic balancer will be loose enough to slide off the reset of the way by using only hand power.
When the harmonic balancer is off, examine the surface where the timing cover seal rides. It should be smooth without any noticeable ridges or groves. If it is damaged, here are sleeves available at the local auto parts store that are a hand press fit to cover the damaged area and provide a proper surface for the seal to ride on. Examine the balancer for damage to the thin rubber ring that mounts the outer hub to the inner hub. If you see any damage or deterioration, now is the time to replace the balancer. Your local auto parts store can provide a stock replacement or Summit Racing has aftermarket replacements. Put the harmonic balancer pulley bolts and the balancer mount bolt in a zip bag or your loose parts bin and store them along with the harmonic balancer and the pulley with the rest of the large parts.

End of harmonic balancer removal

12.) Timing cover removal[/b] Take a picture of the timing pointer and how it is mounted before removing the nuts that secure it to the timing cover. You’ll be glad you did when it comes time to reassemble things. Done incorrectly the timing pointer will get bent and mangled the first time the engine cranks over…Don’t ask me how I know…

13.) Remove the bolts that hold the timing cover in place; don’t forget the 2 small bolts that are on the bottom of the oil pan. There may be 2 locator bushings on the lower part of the timing cover that are pressed into the engine block. Some tugging and wiggling will be necessary to get the timing cover off of them; leave them stuck in the engine block if possible. Put the timing cover bolts in a zip bag or your loose parts bin. Take a box cutter or similar tool and cut off the exposed pan gasket where it disappears under the engine block and throw it away. This is part of the preparation for the new gasket that will go here.

14.) Now for the most tiring, time consuming and demanding part of this job; removing ALL of the old gasket traces from the engine block and timing chain cover. Scrape and clean until you are bored, scrape and clean until you are tired of it and then scrape and clean some more. In order to seal properly, gaskets have to seat against clean, bare metal. A thin film of silicone gasket sealer helps, but is not a proper substitute for clean mating surfaces for the gaskets. The scraping and cleaning is tiresome, but it is less work than having to do it all over again because the gaskets didn’t seat and seal properly in spite of the excess amount of silicone sealer you applied to all the surfaces.
Set the timing cover aside with the rest of the large parts. Take some plastic sheeting or newspaper and cover the timing chain and the crankshaft to keep the mess you are going to make scraping the old hardened gasket remnants off the engine block out of the timing chain and oil pan. A single edge razor blade scraper is the preferred tool for this job, and you’ll need some quality spare blades. Hopefully, most of the sticking gasket remnants are on the engine block and not on the soft aluminum timing chain cover and water pump.
A stainless steel rotary wire brush in an electric or air drill will be needed to get the really hard gasket material off the iron parts. DO NOT use it on aluminum parts!!! The cast iron resists the cutting action of the rotary brush well enough that it will not remove a significant amount of metal or make any groves or scratches that will cause leaks. DO NOT use ScotchBrite or similar scrubber pads because they can leave behind significant amounts of abrasive grit that can find its way into the engine oiling system and wreak havoc on the engine’s internal parts.

15.) Cleaning, inspection, and preassembly.
Now it’s time to clean and inspect all the parts you removed for damage and corrosion. The rubber hoses connected to the water pump may have become casualties of time, wear and of being removed, so be prepared to buy new ones. Replace all of the non-worm gear type hose clamps with new hose clamps. Home Depot or Lowes plumbing dept. will have them cheaper than the auto parts stores. Buy a 5 or even 10 clamp package of the smaller size hose clamps as shop supplies; you’ll be glad you did. Check the fan clutch to make sure that it has some resistance against being turned with you holding the hub that bolts to the water pump flange. Check the plastic fan blades for cracks and damage. Having a fan blade fly off at 5000 RPM can surely ruin the radiator, the hood and maybe even your whole day. Check the belt for cracks, frayed spots and other visible damage. Turn all the accessory drive pulleys by hand to make sure that they run true and turn smoothly; make sure that they are not bent or cracked. Check the belt tensioner pulley; it should run true and turn smoothly. Check the radiator and fan shroud for evidence of cracks, broken mounts and check the radiator for evidence of leaks. There is a rubber cushion on each of the radiator hold down brackets and another set of cushions where the bottom of the radiator sits in the radiator mount frame. If you remove the bottom cushions, mark which side they came from and their orientation; they are side specific due to the rubber alignment bumps on the side that mounts to the metal support brackets they fit in. Inspect them to make sure that they are present and in good condition. Crawl under the car and spray some non-flammable brake parts cleaner over all the parts that have any oil on the outside. While you are under the car, wipe away and blot up any evidence of coolant leaks you find. This will save you time later on trying to chase leaks that you fixed but didn’t clean up after you fixed them.

Now it is time to take s short break and paint ALL of the bolts under the heads and on the threads with a generous amount of anti-seize. A 1 pound, brush top can of Never Seez is one of the best investments you can make in shop supplies. It costs $20-$25, but it will save you countless hours when you disassemble things next time. Bolts don’t corrode, freeze up or break off if you coat them with generous amounts of Never Seez. And yes, as long as you own the car, there will be a next time…

16.) REASSEMBLY:
It’s time to double check the parts and gasket mating surfaces to make sure that they are clean and have no bits of leftover gasket material, damage to the mating surfaces, dirt or debris. I recommend that you use the following stay in place gasket trick to keep the gasket from shifting out of place during installation. Wipe down the gasket mating surfaces with acetone so that they are perfectly free of oil, debris and dirt. Mock fit the gasket so that you know which side faces the water pump. Spray the gasket mating surface of the water pump with weather strip adhesive and also spray the pump gasket side that mates to the water pump. Follow the instructions on the can as to drying time; the surfaces should be tacky, but not damp or dry. CAREFULLY align the gasket with the holes on the water pump; you will have a very limited opportunity to reposition the gasket once it is pressed in place. Apply a thin coat of silicone gasket sealer to the timing cover face around the water passages. Remember that the silicone sealer starts to set within 3-5 minutes and you want to assemble it while it is still soft and sticky. Bolt the water pump to the timing cover using the 3 short bolts across the top of the water pump; torque to 15-18 ft/lbs or 180-210 in/lbs.

17.) Now comes the fun part: assembling the timing cover. If you are reusing your old timing cover, use a punch and hammer to drive the harmonic balancer old seal out from the inside. Apply a thin coat of silicone sealer to the timing cover where the new seal will sit. Use a 2x4 block of wood larger than the seal or a seal driver to tap the seal in place. The block of wood method works good, but you have to watch carefully to make sure that the seal is going in straight. When the metal flange of the seal is flush all around with the face of the timing cover, you are done with the seal. Make sure that the timing cover and pan gasket surfaces are absolutely clean. Use a paper towel or clean rag saturated with acetone to wipe them down. Make two or more passes until the rag or paper towel comes away perfectly clean. Make careful note of which side of the gasket mate with the timing chain cover. Take some weather strip adhesive and spray the timing chain cover and the timing chain cover gasket side that mates with the timing chain cover. Let it get tacky as you did with the water pump gasket. CAREFULLY line the gasket up with the timing chain cover and then press it in place. Make sure of the alignment is correct, because you won’t have much opportunity to move it once it is pressed in place.

I’m going to make some of you cringe, but the next step will help insure a leak free installation. Remember that I told you to cut away the old pan gasket flush with the engine block? Here’s why…

Take a Felpro OS 34508 R one piece silicone rubber pan gasket and mock fit it to the timing cover. Be sure to press it tightly into the curved bottom of the timing cover; when you are satisfied that it fits perfectly, then proceed to the next step. Stand the assembly on the workbench and press the assembled timing cover and gasket down on the bench. When you have it positioned correctly, the flat bottom end of the timing cover is firmly pressing down on the pan gasket. Use a box cutter knife or ball point pen to mark the place where the pan gasket extends beyond the timing cover. Do the same thing to the other side; the closer you are to having the cut or mark exactly at the edge of the timing cover flange where it meets the engine block, the better results you are going to have. Next take a pair of sheet metal shears and cut the gasket where you made the mark. The gasket has a metal core, so a good pair of sheet metal shears is needed to do the job properly. Now you have horseshoe piece of the gasket that perfectly fits the timing cover. Take a tube of regular superglue and run a stream of it around the edges of the timing cover gasket surfaces. Then press the horseshoe shaped section of the pan gasket into place; start with center piece first and work towards the ends. Press hard, keep the gasket lined up with the sides and the holes. When done correctly, the gasket looks like it was made as part of the timing chain cover; no gaps, no out of place holes, all the edges line up perfectly. The superglue may be slow to completely set, but you can use that to your advantage. Some small pinch clamps or clothes pins (remember those?) may be useful to hold the gasket in place until the superglue completely sets, so be sure to have them close at hand. Set the timing chain cover aside for 30 minutes or more to give the superglue time to set. Once it sets, the gasket isn’t moving or slipping out of place no matter what you do. You’ll welcome that assurance about the time you try to maneuver the timing chain cover in place while working to get it lined up properly. Take your silicone sealer and make 2 good size streams where you cut the old pan gasket off at the engine block; that will seal the new gasket to the old gasket, engine block and oil pan. Smear a thin layer of your silicone sealer all along the oil pan mating surfaces, with a little extra added to the curved section of the oil pan where it fits to the timing chain cover. Smear some more of the silicone sealer on the engine block where the timing chain cover fits and especially around the water port openings.

18.) Put the short heater feed hose and thermostat bypass hose on the water pump along with the 4 hose clamps. All of the hose clamps will need to be oriented so that the screw head is on the driver’s side facing forward or up. Some twisting and turning will be needed to get the hoses in place. Before you tighten any hose clamps, work on getting the timing chain cover in place. The silicone sealer is setting while you are working to get the hoses properly installed and positioned. Some extra effort will be needed to get the timing cover in place to slide over the locator dowel sleeves, but keep at it. You may find that using the long bolts to pull everything in place works or putting the bolts in the lower part of the timing chain works best. A 2x4 wooden block may be used along with a hammer to help seat the timing chain cover in place over the alignment dowels. Put the rest of the 5/16” water pump and timing cover bolts in place and torque them all down 180-210 in/lbs. The 2 smaller oil pan bolts get tightened to72–108 in/lbs. The timing pointer uses 2 studs to mount it, if you were smart; you took a picture of it before you removed it. Bolt back on in the same manner shown in the picture.

19.) Harmonic balancer installation
Use a clean paper towel to apply a film of motor oil to the crankshaft and to the harmonic balancer surface where the seal rides; wipe it on and spread it all around. Line the keyway slot in the balancer up with the crankshaft key. Slide the harmonic balancer on the crankshaft and install the bolt and washer. If your car is a 5 speed, put it in 5th gear and set the parking brake so that the harmonic balancer doesn’t turn when you try to tighten the bolt. If your car has an auto trans, a chain wrench like those used to remove oil filters may do the trick. Apply it to the harmonic balancer ribs that protrude from the rear of the balancer. A long pipe wrench may also be applied to the same ribs to prevent the engine from turning. Use a 15/16” socket and a short extension for the harmonic balancer mount bolt; tighten it to 70-90 ft/lbs. Now is the time to use the harmonic balancer bolt & the 15/16” socket to rotate the engine through at least 2 revolutions while you watch the clearance between the harmonic balancer and the timing pointer is sufficient to prevent damage to the timing pointer. DON’T try to use the starter to turn the engine when you do this; you may damage the pointer before you can stop cranking the engine.
Install the harmonic balancer pulley and secure it in place with the 4 grade 8 bolts; they will have 6 radial marks stamped on their heads. Tighten the bolts to 35-50 ft/lbs.

20.) Now that you have timing chain cover/water pump assembly bolted in place, go back and move the 4 hose clamps into their final positions and tighten them securely. You may need to twist, turn and tug to get the clamps properly positioned, but do it now because it gets harder with the fan blades and radiator shroud in place Install the lower radiator hose on the water pump and position the clamp so that it is easily accessible. Some tape with one end folded over to make a pull tab is one way to secure the clamp in position so that it doesn’t turn or slide out of position. When you have the hose and clamp just like you want it and don’t plan of moving them when the work is done, tighten the clamp and pull the tape off.

21.) Install the power steering and A/C compressor mount plate, and coat the studs with Never Seez if you haven’t already done so. Put on the nuts from the 3 studs on the water pump, and the 2 power steering mount bolts and the 3 bolts that secure the A/C compressor (if present) to the A/C & PS mount plate. Tighten one bolt on the rear of the lower A/C mount; this will require a long extension and maybe a universal joint socket.

22.) Mount the fan/clutch assembly on the water pump shaft. A 5/16” fine thread bolt with the head cut off makes an excellent alignment aid; screw it into one of the bolt holes. I usually file the end of the bolt to a smooth point to assist in getting it started in a blind location where it is hard to see where the tapped hole is located. Once you have the bolt holes lined up, install the water pump pulley, fan assembly and then fan mount bolts. A 7/16” flat ratchet or gearwrench is a handy tool to use about this time. The alignment aid bolt is usually the last thing you remove when mounting the fan assembly in place.

Install the fan shroud and set it as far back as you can get it. Put the cardboard in front of the fan and shroud and put the lower radiator support cushions back in place if you removed the. Remember that they are side specific and only properly fit one way. Position the radiator and lower it in place; the cardboard will protect the radiator from dings and other damage. Then install the upper radiator hold down brackets and cushions and install the bolts. Don’t tighten them until you are absolutely certain that the radiator is correctly seated in the lower radiator mount cushions. You’ll have to crawl under the car to see if the radiator is sitting perfectly in them. Move the radiator side to side until it is seated squarely in both cushions. Fail to do this and you will rub a hole in the radiator tanks and possibly damage one or more to the tubes.

The fan shroud bottom fits into 2 slip clips that are part of the lower radiator cross brace. They position the shroud so that it doesn’t move forward or backward. The top of the shroud bolts to the upper radiator top cross brace; there is a little maneuver room to move the shroud side to side and up and down. This is the crucial point because there is limited clearance between the tips of the fan blades and the radiator shroud. Rotate the fan blades and make sure that there is at least a finger width of space between the fan blade tips and the shroud. On my car, the shroud set a little bit high and it took some effort to get the shroud pushed down enough so that the fan blade tips didn’t scrape the bottom shroud opening. It is worthy to note that engine torque will lift the engine and decrease the clearance between the top of the shroud opening and the fan blades. Try to keep that in mind when you are bolting everything up after a final fitting.

23.) Now that the radiator is bolted in place, connect the upper and lower radiator hoses and tighten the hose clamps. Remember the tape trick to hold the lower clamp in place so that when you put a socket or screwdriver on them that the clamp doesn’t move out of position. I prefer to have the screw heads facing either up or forward so that they can be tightened without having to crawl under the car to get to them. If you have transmission cooler lines, uncap them along with the fittings on the radiator and install the lines at this time.
Install the serpentine belt; if you have anything but a stock belt routing, now this time to refer to the picture you took of the belt routing. Otherwise, use the belt routing diagram that is on the front radiator cross brace. Make sure that the belt fits inside the pulley flanges and isn’t hanging off the edge of any of the pulleys.

Take a survey of the engine compartment; you should have picked up and accounted for all of the tools, fasteners and miscellaneous stuff and stored it out of the way. Connect the battery and watch out for big sparks when you do. Big sparks or loud pops are an indication that you either left something turned on or there is a tool, nut or bolt lying on top of a bare electrical connector or wire. You may see a small spark due to the radio and computer memory powering on. If there are no big sparks or indication of an excessive electrical draw, then tighten down the negative battery cable.

Make sure that if you drained the radiator by using the removable plug or drain valve that it is plugged or tightened properly so that the coolant will not leak out. It takes somewhere around 2 -3 gallons of coolant depending on the radiator size and how much coolant drains out of the engine block while you are working on the engine.

24.) Final inspection time
Check all the bolts, screws and clamps to make sure that they are all properly tightened, and the fan blade turns freely without scraping the fan shroud. There should be no loose hoses or disconnected electrical components and no tools or other items left lying on top of the engine. Crank it up and listen for any unusual noises (I heard the timing pointer as it repeatedly hit the harmonic balancer); hopefully there will only the normal sounds of the engine running. Add coolant if necessary and then run the engine up to operating temperature to check the coolant level again. Look for leaks and be prepared to crawl under the car to do so. If there are no leaks, no unusual noises and nothing catches your eye or ear, take it for a short test drive. Keep an eye on the temp gauge, you may find that the coolant level is little low. When you get back, let the engine cool to the point where it is safe to remove the radiator cap and check the coolant level. Add coolant to the radiator and overflow tank to bring them up to the correct level. Do a second leak inspection, crawl under the car to check it out. Put the large piece of cardboard you used to protect the radiator during removal and installation under the engine to act as a drip indicator. No drip marks on the cardboard over the next few days is a good thing; you have fixed your leak or leaks.

25.) Follow up:
After 10 or so hours of engine operation, change the oil and oil filter. All the debris from scraping and removing the old gasket pieces have made their way down into the oil pan and oil filter, so it is recommended to change them. Look for evidence of coolant contaminating the oil; milky oil is not good. It may be due to the coolant that dripped into the open oil pan while the timing cover was off. Or you may have a hidden leak from a gasket that got damaged during installation. Do another leak inspection while you are draining the oil, hopefully it will all be clean and dry. You may also want to change the coolant if you reused it. No problems found and no drips on the cardboard mean a happy owner :D. Enjoy driving a leak free 5.0 Mustang!
 

93silverlx50

Member
Jun 12, 2017
66
5
18
41
Thanks for all the input. I've got a NOS TFI module headed my way and a fatfoxx relocation kit.

Now for the balancer. I see a 50oz and a 28oz. Would a 28oz be better for my application?
 

93silverlx50

Member
Jun 12, 2017
66
5
18
41
After reading the first post over again to things jump out at me,
Msd ignition box/boost control
Slow cranking condition
Did you by it with these problems?

When I bought the car it ran very good, struggled every now and again with slow cranking but that's it. Over the last 5 years the car has sat a lot. Like never cranked sat so I know Id have issues for a while.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,317
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234
74
Dublin GA
lowendmac.com
Thanks for all the input. I've got a NOS TFI module headed my way and a fatfoxx relocation kit.

Now for the balancer. I see a 50oz and a 28oz. Would a 28oz be better for my application?
You need a 50 oz. balancer in order to match the engine's internal balance.


Slow crank problem.

No Crank checklist for 5.0 Mustangs

Revised 24-Oct-2013 to update voltage drop figures.

No crank, slow crank and stuck starter solenoid problems have the same root causes – low battery voltage and poor connections. For that reason, they are grouped together.
Use the same initial group of tests to find the root cause of slow crank, no crank and stuck solenoid problems.

Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…


1.) Will the car start if it is jumped? Then clean battery terminals and check battery for low charge and dead cells. A good battery will measure 12-13 volts at full charge with the ignition switch in the Run position but without the engine running.
A voltmeter placed across the battery terminals should show a minimum of 9.5-10 volts when the ignition switch is turned to the Start position and the starter engages or tries to engage. Less than this will result in a clicking solenoid, or slow cranking (if it cranks at all) or a starter solenoid that sticks and welds the contacts together.

Most auto parts stores will check your battery for free. It does not have to be installed in the car to have it checked; you can carry it with you to the auto parts store.

The battery posts and inside of the battery post terminals should be scraped clean with a knife or battery post cleaner tool. This little trick will fix a surprising number of no start problems.

The clamp on with 2 bolts battery terminal ends are a known problem causer. Any place you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Corroded connections do not conduct electricity well. Avoid them like the plague...

If the starter solenoid welds the contacts, then the starter will attempt to run anytime there is power in the battery. The cables and solenoid will get very hot, and may even start smoking. The temporary fix for a welded starter solenoid is to disconnect the battery and smack the back of the solenoid housing a sharp blow with a hammer. This may cause the contacts to unstick and work normally for a while.


A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .

attachment.php?attachmentid=64167&stc=1&d=1286329941.gif


Voltage drops should not exceed the following:
200 mV Wire or cable
300 mV Switch or solenoid
100 mV Ground
0.0V Connections
A voltage drop lower that spec is always acceptable.

2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean them up.

3.) Jump the big terminals on the starter solenoid next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

The rest of the tech note only concerns no crank problems. If your problem was a stuck solenoid, go back to step 1.

4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it cranks, the relay is good and your problem is in the rest of the circuit.

5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems.

Typical start circuit...
Diagram courtesy of Tmoss & Stang&2birds
attachment.php?attachmentid=21328&d=1080916057.gif



6.) Pull the starter and take it to AutoZone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.


Starter solenoid wiring for 86-91 Mustang
attachment.php?attachmentid=52294&stc=1&d=1192414749.gif



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
attachment.php?attachmentid=53216&stc=1&d=1201020653.gif


Electrical checks for the switches and starter solenoid

Remove the small red/blue wire from the starter solenoid. Use a screwdriver to bridge the connection from the battery positive connection on the starter solenoid to the small screw where the red/blue wire was connected. The starter should crank the engine. If it does not, the starter solenoid is defective or the battery lacks sufficient charge to crank the engine.

If the starter does crank the engine, the problem is in the clutch safety circuit (5 speed) or Neutral Sense Switch (auto trans) or ignition switch.


See the Typical start circuit diagram above for wiring information for troubleshooting.

You will need a voltmeter or test lamp for the rest of the checks. Connect one lead of the voltmeter or test lamp to ground. The other lead will connect to the item under test.
Look for 12 volts on the white/pink wire when the ignition switch is turned to the Start position. Check the ignition switch first.
No 12 volts, replace the ignition switch.

The next step will require you to push the clutch pedal to the floor (5 speed) or put the transmission in neutral (auto trans) while the ignition switch is turned to the Start position.
Good 12 volts, check the clutch safety switch (5 speed) or Neutral Sense Switch (auto trans) for good 12 volts on both sides of the switches. No 12 volts on both sides of the switch and the switches are defective or out of adjustment. Check the wiring for bad connections while you are at it.
 

93silverlx50

Member
Jun 12, 2017
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UPDATE:

I've replaced the TFI module with a new motorcraft, replaced harmonic balancer, ignition switch, negative battery cable due to secondary ground broken and the car still will not start.

I ran key on engine off codes and got these:

34 insufficient EGR flow

85 canister purge solenoid circuit failure and shift solenoid 3/4 - 4/3

34 repeat

85 repeat

10 Cylinder #1 Has a problem

96 fuel pump secondary circuit fault / high speed fuel pump relay open

What else can I do?
 

jrichker

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The 10 code is a spacer code that the computer sends out to tell the scanner or code reader that it ready to dump codes.

Only the 96 code would prevent the engine from starting. That would prevent the fuel pump from running.

You said that you have spark.
You said that you fuel pressure.
You said that you that the fuel injectors pulsing. You used Use the noid tester to verify.

When you checked the timing with the timing light while cranking the engine, did the flash line up with the timing marks?

Bypass the MSD box since that is #2 item in the no start checklist.
Have you fixed the slow crank problem?

MSD wiring:

msd-ford-installation-w-harness-gif.71658.gif

msd-ford-installation-wo-harness-gif.71659.gif


Instead of using the battery negative terminal, attach the heavy gauge black wire to the body ground point by the windshield washer filler.

The battery common ground is a 10 gauge pigtail with the computer ground attached to it.
Picture courtesy timewarped1972
ground.jpg
 

93silverlx50

Member
Jun 12, 2017
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I have done the noid light test and the injectors are firing.

Regarding timing while cranking, I use the timing light while I had someone cranking the motor. The timing light is flashing but does NOT show the marks on the HB. I stabbed the dizzy under compression with the HB at TDC. I not sure why it's not showing any marks while cranking.

The timing light seems to be flashi g very slowly.
 

93silverlx50

Member
Jun 12, 2017
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I adjusted the timing and set it at 10* while cranking. Still no start but smells like gas after about 5 seconds of constant cranking.

So bypassing the MSD box, just unplug factory coil pigtail plug that is plugged into the MSD wiring and then plug it into the coil, is that it?

If so, still won't start.
 

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93silverlx50

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Jun 12, 2017
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UPDATE

So I pulled the dizzy again and now timing is at 10*. I've been working on the car over the last 2 days, about 14 hrs total. Today when installing the new TFI I also installed the fatfoxx relocation kit. Now I have NO spark at plugs and no spark off the coil. Also did the noid light test AGAIN on the injectors. They are no longer firing. WTF.
 

93silverlx50

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Jun 12, 2017
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I got the car started today, it cranks fine but stumbled and sputtered before finally starting. I had the spout out and timed it at 10*. I put the spout in and it reved to about 1800 RPMs where it stayed. Since I replaced the IAB I never reset the idle or ECU. I unplugged the IAB, adjusted the idle back down to 700-800rpms. I checked the timing and with each flash of the timing light I was getting different readings, like 6 to 10 degrees off with each flash. When I give the car gas, it stumbles and hesitates like it's misfiring. I can also hear a hollow tin poping sound that sounds like its coming directly out of the cone air filter (yes i know the filter needs to be moved as its out uncovered in the engine bay).

After adjusting the idle I went to check timing without the spout so when I unplugged the spout the engine died. I tried restarting it and got the slow cranking again, presumably because the motor is hot. The starter is new but a regular size from advanced auto parts and I've got BBK longtubes, could it be heat soaked even being new?

As far as the timing light giving different readings and the car seemingly misfiring, what could that be?

I ran the key on engine running codes and got 12 (before I adjusted the idle) and 21 both twice.
 
Last edited:

jrichker

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Suspect #1 MSD = May Suddenly Die = #2 item on the Cranks OK, but No Start Checklist for Fuel Injected Mustangs.


Suspect #2 open fuse link in ignition circuit coming from the ignition switch.


The following are diagrams courtesy of Tmoss & Stang&2birds


Ignition switch wiring


Fuel, alternator, A/C and ignition wiring



PM me your email address and I will send you a complete Ford Factory 89 Mustang electrical diagram set. The zip file is 2.5 MB and is too big to fit through Stangnet's email gateway.
The plug shapes on the diagrams match the plug shapes on the actual plug. The diagram is divided up by the layout of the car. The first diagram is for the very front of the car, and it works its way to the rear of the car.
89 Mustang wiring diagrams zip package–

They are in a zip file format to reduce the size of the package. If you don't have Windows 7 or Windows 8, you’ll need WinZip or other Windows archive tool to extract them from the zip file.. See www.majorgeeks.com - Download Freeware and Shareware Computer Utilities for a free download.

The diagrams show the location area and the connectors are drawn to the same shape as those in the car.

You will need the Adobe Acrobat viewer which is also a free download – www.adobe.com/products/acrobat/readstep2.html - Adobe Reader download - All versions
 

93silverlx50

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Jun 12, 2017
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So the car will eventually start as long as it's NOT warm. Seems like it helps to start if i put the throttle to the floor. It cranks for awhile and will eventually sputter and start. The idle Bob's up and down continuously. I'm going to review the surging idle checklist again to see if something there is causing the hard starting, stumbling and hesitation. Basically car almost runs like it's in limp mode.

Fuel pressure is at 38-40lbs.

I've replaced the flooding parts:

Ecu, iab, distributor, Tfi module, ignition switch, negative battery cable and cleaned grounds, tps, cleaned MAF.
 

93silverlx50

Member
Jun 12, 2017
66
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UPDATE

I reset the IAB, ECU and verified .98 volts at the tps, it was previously at .68.

So the car will start IF I give it throttle, not full throttle but about anywjere netween half to full throttle. It cranks awhile and sputters but will start if I give it throttle.

The car has the emissions stuff deleted and runs very rich. The exhaust fuel smell stays on you all day.

I pulled codes both running and off. Here they are:

KOER
92
34
92
34

KOEO
34
85
34
85
10
29
34
66
96

Car still runs like crap if I give it any throttle, like it's missing, the RPMs accelerate rough and after a delay when I hit the pedal. It will idle hunt a little bit too, 200 RPMs up and down.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
I went back and read your first post, thinking there was more to this, how long has the s trim been on the car? Did you purchase the car this way or build it? Now this is just some inexperienced advice but you may look into something being amiss with the msd or the boost timing control thingy or your timing chain being worn.
I think maybe through the 30 or so posts that its been forgotten that this is not a na, normal bolt on setup, there are other factors here in play.
 

93silverlx50

Member
Jun 12, 2017
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So I bought the car since 2001. Had a shop pull the 184000 motor and put in a buddy's 306 motor with about 8000 miles on it. Thats when i added the blower. In 2011 the car started sitting, a lot. In 2015 it was never cranked over. I sold it last year and after about a year I found it on CL and bought it back.

I bypassed the MSD box to test it but I'm not sure how the timing control box is hooked up.

I also recently pulled the upper intake manifold to check for a coolant leak around the lower intake manifold. I'll be pulling the upper again to ensure everything is lined up correctly and changing the fuel filter and cleaning the MAF again.
 

imp

Mustang Master
Jul 13, 2017
531
105
83
69
I went back and read your first post, thinking there was more to this, how long has the s trim been on the car? Did you purchase the car this way or build it? Now this is just some inexperienced advice but you may look into something being amiss with the msd or the boost timing control thingy or your timing chain being worn.
I think maybe through the 30 or so posts that its been forgotten that this is not a na, normal bolt on setup, there are other factors here in play.
@karthief
WTH is "S" trim, if I may be so stupid to ask? imp
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
17,852
5,793
193
polk county florida
Well since you ask me, the well know s trim expert, they were first developed for the rotary engine in planes around wwll, they redirected air through a baffeled tube to keep water from being ingested into the engine when flying through heavy rain.

They were also used by ducks to keep their butt hole water tight. :rolleyes:
 

93silverlx50

Member
Jun 12, 2017
66
5
18
41
UPDATE

I reset the IAB, ECU and verified .98 volts at the tps, it was previously at .68.

So the car will start IF I give it throttle, not full throttle but about anywjere netween half to full throttle. It cranks awhile and sputters but will start if I give it throttle.

The car has the emissions stuff deleted and runs very rich. The exhaust fuel smell stays on you all day.

I pulled codes both running and off. Here they are:

KOER
92
34
92
34

KOEO
34
85
34
85
10
29
34
66
96

Car still runs like crap if I give it any throttle, like it's missing, the RPMs accelerate rough and after a delay when I hit the pedal. It will idle hunt a little bit too, 200 RPMs up and down.

I tested the TFI module with a multimeter and it tests within range.

I noticed the pickup stator in the distributor was rusted so I replaced it with a Motorcraft unit. Car acts the same. I have no idea what to do now.
 

jrichker

StangNet's favorite TOOL
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Code 42 & 92 (engine running) System rich - Fuel control or (memory) System was rich for 15 seconds or more (no HO2S switching) - Fuel control. Look for leaking injectors, fuel pressure too high, cylinder(s) not firing due to bad ignition.

Code 42 passenger side sensor, as viewed from the driver's seat
Code 92 is the driver side sensor, as viewed from the driver's seat..

The following is a Quote from Charles O. Probst, Ford fuel Injection & Electronic Engine control:
"When the mixture is lean, the exhaust gas has oxygen, about the same amount as the ambient air. So the sensor will generate less than 400 Millivolts. Remember lean = less voltage.

When the mixture is rich, there's less oxygen in the exhaust than in the ambient air , so voltage is generated between the two sides of the tip. The voltage is greater than 600 millivolts. Remember rich = more voltage.

Here's a tip: the newer the sensor, the more the voltage changes, swinging from as low as 0.1 volt to as much as 0.9 volt. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen.

Because the oxygen sensor generates its own voltage, never apply voltage and never measure resistance of the sensor circuit. To measure voltage signals, use an analog voltmeter with a high input impedance, at least 10 megohms. Remember, a digital voltmeter will average a changing voltage." End Quote

Testing the O2 sensors 87-93 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear.


Backside view of the computer wiring connector:
a9x-series-computer-connector-wire-side-view-gif.71316.gif


87-90 5.0 Mustangs:
Computer pin 43 Dark blue/Lt green – LH O2 sensor
Computer pin 29 Dark Green/Pink – RH O2 sensor
The computer pins are 29 (LH O2 with a dark green/pink wire) and 43 (RH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.

91-93 5.0 Mustangs:
Computer pin 43 Red/Black – LH O2 sensor
Computer pin 29 Gray/Lt blue – RH O2 sensor
The computer pins are 29 (LH O2 with a Gray/Lt blue wire) and 43 (RH O2 with a Red/Black wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.


Testing the O2 sensors 94-95 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear. The computer pins are 29 (LH O2 with a red/black wire) and 27 (RH O2 with a gray/lt blue wire). Use pin 32 (gray/red wire) to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.



There is a fuse link for the O2 sensor heater power. According to Ranchero50, it is in the wiring near the passenger side hood hinge. Measuring the voltages will give a clue if it has shorted to the O2 sensor signal lead. The O2 sensor voltage should switch between .2-.9 volt at idle.

Code 34 Or 334 - EGR voltage above closed limit –

Revised 26-Sep-2011 to add EGR cleaning and movement test for pintle when vacuum is applied to diaphragm

Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. If it leaks, there is carbon stuck on the pintle valve seat clean or, replace the EGR valve ($85-$95).

Recommended procedure for cleaning the EGR:
Conventional cleaning methods like throttle body cleaner aren’t very effective. The best method is a soak type cleaner used for carburetors. If you are into fixing motorcycles, jet skis, snowmobiles or anything else with a small carburetor, you probably have used the one gallon soak cleaners like Gunk or Berryman. One of the two should be available at your local auto parts store for $22-$29. There is a basket to set the parts in while they are soaking. Soak the metal body in the carb cleaner overnight. Don’t immerse the diaphragm side, since the carb cleaner may damage the diaphragm. If you get any of the carb cleaner on the diaphragm, rinse it off with water immediately. Rinse the part off with water and blow it dry with compressed air. Once it has dried, try blowing through the either hole and it should block the air flow. Do not put parts with water on them or in them in the carb cleaner. If you do, it will weaken the carb cleaner and it won’t clean as effectively.

Gunk Dip type carb & parts soaker:



If you have a handy vacuum source, apply it to the diaphragm and watch to see if the pintle moves freely. Try blowing air through either side and make sure it flows when the pintle retracts and blocks when the pintle is seated. If it does not, replace the EGR.


If the blow by test passes, and you have replaced the sensor, then you have electrical ground problems. Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1.5 ohm. Next check the resistance between the black/white wire and the negative battery post. It should be less than 1.5 ohm.

Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

Let’s put on our Inspector Gadget propeller head beanies and think about how this works:
The EGR sensor is a variable resistor with ground on one leg and Vref (5 volts) on the other. Its’ resistance ranges from 4000 to 5500 Ohms measured between Vref & ground, depending on the sensor. The center connection of the variable resistor is the slider that moves in response to the amount of vacuum applied. The slider has some minimum value of resistance greater than 100 ohms so that the computer always sees a voltage present at its’ input. If the value was 0 ohms, there would be no voltage output. Then the computer would not be able to distinguish between a properly functioning sensor and one that had a broken wire or bad connection. The EGR I have in hand reads 700 Ohms between the slider (EPV) and ground (SIG RTN) at rest with no vacuum applied. The EGR valve or sensor may cause the voltage to be above closed limits due to the manufacturing tolerances that cause the EGR sensor to rest at a higher position than it should.

The following sensors are connected to the white 10 pin connector (salt & pepper engine harness connectors)


This will affect idle quality by diluting the intake air charge


Code 10 is a spacer code and tells the scanner/code reader that the computer is ready to dump codes.


Code 85 CANP solenoid - The Carbon Canister solenoid is inoperative or missing.

Revised 11 –Jan_2015 to add warning about vacuum leaks due to deteriorated hose or missing caps on vacuum lines when the solenoid is removed.

Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.

If you disconnected the carbon canister and failed to properly cap the vacuum line coming from under the upper intake manifold, you will have problems. You will also have problems if the remaining hose coming from under the upper intake manifold or caps for the vacuum line are sucking air.

Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel. The canister is normally mounted on the passenger side frame rail near the smog pump pulley.

Connecting the gas tank vent line directly to the intake manifold will result in fuel vapor being constantly sucked into the intake manifold. There is unmetered fuel that the computer cannot adjust for. The result is poor idle and poor fuel economy.



It does not weigh but a pound or so and helps richen up the cruse mixture. It draws no HP & keeps the car from smelling like gasoline in a closed garage. So with all these good things and no bad ones, why not hook it up & use it?


The purge valve solenoid connector is a dangling wire that is near the ECT sensor and oil filler on the passenger side rocker cover. The actual solenoid valve is down next to the carbon canister. There is about 12"-16" of wire that runs parallel to the canister vent hose that comes off the bottom side of the upper intake manifold. That hose connects one port of the solenoid valve; the other port connects to the carbon canister.

The purge valve solenoid should be available at your local auto parts store.

Purge valve solenoid:



The carbon canister is normally mounted on the passenger side frame rail near the smog pump pulley.
Carbon Canister:
903_AIRTEX%20_pct_2F%20WELLS_7310014_1.jpg




Code 29 - Vehicle Speed Sensor (VSS) is an electronic sender mounted on the speedo pickup gear on the trans. It works the cruse control for both 5 speed and auto trans cars. The VSS is used to tell the computer to speed up the idle as you slow to a stop. This helps keep the engine from stalling when you slow down for a stop sign or stop light.
Check to see if the electrical connector is plugged into it. Clean the connector & contacts with non flammable brake parts cleaner prior to replacing the sensor, as that may fix the problem. The sensor cost is under $30 and it is easy to replace.


Code 66 or 157 MAF below minimum test voltage.

Revised 10-Feb-2014 to add 95-95 Mustang code 157 and 94-95 ECC diagram

Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

Computer connector for 88-93 5.0 Mustangs

Diagrams courtesy of Tmoss and Stang&2Birds

ECC Diagram for 88-90 5.0 Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


ECC Diagram for 91-93 5.0 Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif


94-95 Diagram for 94-95 5.0 Mustangs

94-95_5.0_EEC_Wiring_Diagram.gif


There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables. Changes in RPM causes the airflow to increase or decrease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

89-90 Model cars: Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

91-95 Model cars: Measure the MAF output at pins C & D on the MAF connector light blue/red and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.


At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.

Actually MAF pins C & D float with reference to ground. The signal output of the MAF is a differential amplifier setup. Pins C & D both carry the output signal, but one pin's output is inverted from the other. The difference in signal between C & D is what the computer's input circuit is looking for. The difference in the two outputs helps cancel out electrical noise generated by the ignition system and other components. Since the noise will be of the same polarity, wave shape and magnitude, the differential input of the computer electronically subtracts it from the signal. Then it passes the signal on to an Analog to Digital converter section inside the computer's CPU chip.


Code 96 causes & tests 91-93 models. – KOEO- Fuel pump monitor circuit shows no power - Fuel pump relay or battery power feed was open - Power / Fuel Pump Circuits. The fuel pump circuit lost power at one time or another.

Revised 24-Mar-2017 to add text about the A/C Wide Open Throttle relay and using the wire colors to identify which relay is the fuel pump relay

Clear the codes by disconnecting the battery and turning on the headlights for about 5 minutes before reconnecting the battery. This will clear any remaining codes. Drive the car for several days and dump the codes again. In many cases, this clears the 96 code.

Look for a failing fuel pump relay, bad connections or broken wiring. On 91 model cars, the fuel pump relay is under the driver’s seat. The fuel pump relay is located under the Mass Air Meter on Fox bodied stangs built after 91. It can be confused with the A/C Wide Open Throttle relay which is in the same area. Use the wire colors as shown in the diagram below to identify which relay is the fuel pump relay.

Diagram of the fuel pump wiring for 91-93 cars.


Look for power at the fuel pump - the fuel pump has a connector at the rear of the car with a pink/black wire and a black wire that goes to the fuel pump. The pink/black wire should be hot when the test connector is jumpered to the test position. To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground. No voltage when jumpered, check the fuel pump relay and fuse links.




Power feed: Look for 12 volts at the pink/black wire (power source for fuel pump relay). No voltage or low voltage, bad fuse link, bad wiring, or connections. Remember that on 92 or later models the fuel pump relay is located under the Mass Air meter. Watch out for the WOT A/C control relay on these cars, as it is located in the same place and can easily be mistaken for the fuel pump relay.

Relay: Turn on the key and jumper the ECC test connector as previously described. Look for 12 volts at the dark green\yellow wire (relay controlled power for the fuel pump). No voltage there means that the relay has failed, or there is a broken wire in the relay control circuit. Be sure to closely check the condition of the relay, wiring & socket for corrosion and damage.



91-93 Models:
Using the diagram, check the dark green/yellow wire from the fuel pump relay: you should see 12 volts or so. If not the relay has failed or is intermittent. Check the inertia switch: on a hatch it is on the driver’s side by the taillight. Look for a black rubber plug that pops out: if you don't find it, then loosen up the plastic trim. Check for voltage on both sides of the switch. If there is voltage on both sides, then check the Pink/black wire on the fuel pump relay: it is the power feed to the fuel pump. Good voltage there, then the fuel pump is the likely culprit since it is getting power. No voltage there, check the Pink/black wire, it is the power feed to the fuel pump relay & has a fuse link in it. Good voltage there & at the dark green/yellow wire, swap the relay.

All testing is done with the ignition switch in the Run position. Do not forget this crucial step.

The pink/black wire should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the fuse link for the fuel pump has opened up.

With the test jumper in place the green/yellow wire should be the same voltage as the pink/black wire +/- 0.25 volt.

If not, look at the red wire: should have the same voltage as the battery positive terminal +/- 0.25 volt.
If not, then check the yellow wire on the EEC relay located on top of the computer. This one is hard to get to. It should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the fuse link for the computer has opened up.

If the red wire does not have the same voltage as the battery positive terminal +/- 0.25 volt and the yellow wire on the EEC relay does, then check the red/green wire on the EEC relay. It should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the ignition switch is defective or the fuse link in the ignition wiring harness has opened up, or the EEC relay is defective.

All testing is done with the ignition switch in the Run position. Do not forget this crucial step.

The pink/black wire s should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the fuse link for the fuel pump has opened up.

With the test jumper in place the green/yellow wire should be the same voltage as the pink/black wire +/- 0.25 volt.

If not, look at the red wire: should have the same voltage as the battery positive terminal +/- 0.25 volt.
If not, then check the yellow wire on the EEC relay located on top of the computer. This one is hard to get to. It should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the fuse link for the computer has opened up.

If the red wire does not have the same voltage as the battery positive terminal +/- 0.25 volt and the yellow wire on the EEC relay does, then check the red/green wire on the EEC relay. It should have the same voltage as the battery positive terminal +/- 0.25 volt. If not, then the ignition switch is defective or the fuse link in the ignition wiring harness has opened up, or the EEC relay is defective.

Diagram courtesy of Tmoss & Stang&2birds
IgnitionSwitchWiring.gif





See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg
 
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