Cranks OK, but No Start Checklist for Fuel Injected Mustangs

Trey567

New Member
Oct 31, 2014
4
0
1
36
Hi guys it looks like I found the culprit, or at least a major reason why. A badly corroded fuel pump and rust in my gas tank was what I found today. I've attached pics of how bad the pump is corroded. I had the car sitting for about two years now. Any insight on how to prevent my new fuel pump from corroding like this, and getting rust out of my gas tank will be helpful . Thanks in advance guys.
 

Attachments

  • IMG_0904.JPG
    IMG_0904.JPG
    148 KB · Views: 317
  • IMG_0906.JPG
    IMG_0906.JPG
    158.7 KB · Views: 278
  • IMG_0905.JPG
    IMG_0905.JPG
    134.5 KB · Views: 286
  • IMG_0902.JPG
    IMG_0902.JPG
    149.8 KB · Views: 293
  • IMG_0908.JPG
    IMG_0908.JPG
    137.9 KB · Views: 286
  • IMG_0909.JPG
    IMG_0909.JPG
    109.2 KB · Views: 271
  • Sponsors(?)


jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
Full tank of gas, preferably alcohol free and a good shot of Stabil fuel stabilizer. The full tank will greatly reduce condensation, and the no alcohol fuel will reduce the tendency to the fuel to soak up moisture.
 
Last edited:

Trey567

New Member
Oct 31, 2014
4
0
1
36
Ok thanks jrichker, another question, should I replace the fuel pump with the stock one or should I upgrade to an aftermarket fuel pump??
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
Ok thanks jrichker, another question, should I replace the fuel pump with the stock one or should I upgrade to an aftermarket fuel pump??
That depends on your future plans for the car.
Here's some help to make an informed decision...

Copied from the FORD RACING PERFORMANCE PARTS catalog:

PROPERLY SIZING FUEL SYSTEM COMPONENTS


Fuel Pumps
The following information is presented assuming the above information has been taken into consideration regarding BSFC, fuel pressure and specific gravity of the fuel being used. Most fuel pumps for electronic fuel injection are rated for flow at 12 volts @ 40 PSI. Most vehicle charging systems operate anywhere from 13.2v to 14.4v. The more voltage you feed a pump, the faster it spins which, obviously, will put out more fuel. Rating a fuel pump at 12 volts then, should offer a fairly conservative fuel flow rating allowing you to safely determine the pump’s ability to supply an adequate amount of fuel for a particular application.

As previously mentioned, engines actually require a certain WEIGHT of fuel, NOT a certain VOLUME of fuel per horsepower. This can offer a bit of confusion since most fuel pumps are rated by volume, and not by weight. To determine the proper fuel pump required, a few mathematical conversions will need to be performed using the following information. There are 3.785 liters in 1 US Gallon. 1 gallon of gasoline (.72 specific gravity @ 65° F) weighs 6.009 LBS.

To be certain that the fuel pump is not run to its very limit, which could potentially be dangerous to the engine, multiply the final output of the fuel pump by 0.9 to determine the capacity of the fuel pump at 90% output. This should offer plenty of ‘cushion’ as to the overall “horsepower capacity” of the fuel pump.

To determine the overall capacity of a fuel pump rated in liters, use the additional following conversions:
(Liters per Hour) / 3.785 = Gallons
Multiply by 6.009 = LBS/HR
Multiply by 0.9 = Capacity at 90%
Divide by BSFC = Horsepower Capacity
So for a 110 LPH fuel pump:
110 / 3.785 = 29.06 Gallons
29.06 x 6.009 = 174.62 LBS/HR
174.62 x 0.9 = 157 LBS/HR @ 90% Capacity
157 / 0.5 = 314 HP safe naturally aspirated “Horsepower Capacity”

Safe “Horsepower Capacity” @ 40 PSI with 12 Volts
60 Liter Pump = 95 LB/HR X .9 = 86 LB/HR, Safe for 170 naturally aspirated Horsepower
88 Liter Pump = 140 LB/HR X .9 = 126 LB/HR, Safe for 250 naturally aspirated Horsepower
110 Liter Pump = 175 LB/HR X .9 = 157 LB/HR, Safe for 315 naturally aspirated Horsepower
155 Liter Pump = 246 LB/HR X .9 = 221 LB/HR, Safe for 440 naturally aspirated Horsepower
190 Liter Pump = 302 LB/HR X .9 = 271 LB/HR, Safe for 540 naturally aspirated Horsepower
255 Liter Pump = 405 LB/HR X .9 = 364 LB/HR, Safe for 700 naturally aspirated Horsepower

Note: For forced induction engines, the above power levels will be reduced because as the pressure required by the pump increases, the flow decreases. In order to do proper fuel pump sizing, a fuel pump map is required, which shows flow rate versus delivery pressure.

That is, a 255 liter per hour pump at 40 PSI may only supply 200 liters per hour at 58 PSI (40 PSI plus 18 lbs of boost). Additionally, if you use a fuel line that is not large enough, this can result in decreased fuel volume due to the pressure drop across the fuel feed line: 255 LPH at the pump may only result in 225 LPH at the fuel rail.


My Comments:

A lot of people oversize the fuel pump by buying a 255LPH pump thinking that the fuel pump regulator will just pass the excess gas back to the tank. It does, but… Did you ever consider that circulating the fuel around as a 255 LPH pump does will cause the gas to pickup engine heat? What happens to hot gasoline? It boils off or pressurizes the fuel tank! With most of the 5.0 Mustangs having the carbon canister removed or disabled, the car stinks like gas, and the gas mileage drops since the hot fuel evaporates away into the air.
 

TX_Snake

New Member
Oct 12, 2014
14
0
1
38
My 91 LX is electrically dead...no lights, no FP, nothing. I have 12V at my battery, but no power anywhere else. I got in the car this evening to go somewhere, turned key to acc and rolled down my window, than hit the starter and it just died. Nothing happened then I lost all power. It is like the car has no battery what so ever.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
Do the headlights work? What happens when you turn on the headlights and honk the horn? Do the lights dim? yes/no. No dimming of the lights and you have a no crank problem. You have a no crank condition that you need to fix before you do anything else.
Do a search for No Crank checklist for 5.0 Mustangs. In are the things you need to check.

Lights dim only slightly:
Does the radio work? Heater? if not then you probably have a bad ignition switch. Start at the top of the checklist and work you way down. One of the checks looks for voltage at the ignition coil.

I don't make house calls and that is why the first post in this thread is the checklist. Print the checklist and DO IT!
 

TX_Snake

New Member
Oct 12, 2014
14
0
1
38
I have no power at all. No lights, radio, etc. it is like the car has no battery in it. Batt shows 12v with a multimeter. even tried to start at solenoid but nothing is happening.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
You have a no 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


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



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



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
attachment.php


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.
 

TX_Snake

New Member
Oct 12, 2014
14
0
1
38
So I followed the procedures and neat I could tell I had a dead starter. Changed starters and same problem. It doesn't matter if I jump the post at the relay or try to turn the key, nothing happens.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
Will the car crank if you jump it to another car with a good battery?
You have a bad connection somewhere. Did you clean the battery terminals real good, both the post and the clamp?

If so, then you get to do the voltage drop test I described in the test path. Remember that to get accurate results you have to do the test with the key turned to the Start position.
 

April5.0

Active User
Jul 8, 2014
11
1
13
40
Hello All,
I have a 95 GT and have been having a "cranks but won't start" issue for about a year. I've gone through the no start check list, replacing the battery, ignition switch, spark plugs, ignition module, coil, distributor (PIP), and am still not getting any spark off the coil. Before I have it towed to the shop to see if they can figure it out, any suggestions? A friend of mine thinks it could be in the factory alarm system? Any help will be much appreciated!!
April
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
@April5.0

How bad do you want to drive the car?
Did you actually step through the checklist? The very first post of this tech note has everything you need to do.
What did you get for the diagnostic checks?
Voltage at the green/red wire on the ignition coil?
What did the Noid light test show?
Or did you just throw parts at it?
 
Last edited:

rbrown777

Member
Jul 22, 2017
13
1
13
Riverview, FL
Car dies, then cranks with no spark.

Hi guys, tagging on as a new member.

After doing a lot of reading through these threads, it's obvious that a lot of people have the same issues with these Ford ignitions. However, it doesn't seem like I'm finding the right solution. I've been through the No Spark tests, but not sure about the results.

The problem started a couple weeks ago, when I replaced my Motorcraft (original DY1074) TFI module, due to a problem with bad spark at high RPM. The new Motorcraft DY1284 module (supercedes the DY1074 from what I understand) made the car feel very strong to 6k RPM. I thought the problem was fixed, and all was good. However, 2 days later, my mustang left me stranded on the highway, and wouldn't restart. I had it towed home, and after some research, decided I had another bad TFI.

I replaced the TFI module, and also bought a rebuilt Motorcraft distributor (in case the PIP sensor was the problem).

This new TFI and distributor ran great, for about an hour. Then died again. I could restart and run for a moment at a time, and was able to limp the mile back home.

Rather than throwing more parts at it, I have been running diagnostic tests (Voltage checks, LED test light), and keep coming up with the same test results. So...I replaced the TFI again, and it died within 30 minutes.

Here's what I've found:
- After the car warms up, it dies like it was turned off with a light switch.
- If I try to restart by leaving the key in the run position after it dies (WITHOUT cycling the key off first), it won't spark at all (verified by timing light on coil wire).
- This seems to be an important part of my ignition problem.
- If I try to restart by turning the key all the way off, and then back on, it starts again (but dies again moments later showing no spark).
- Once the engine cools off, it will run for awhile before it dies again.

Tests:
- I have 12v to both sides of the coil, whether spark or no spark condition.
- When the car is in the 'no spark' mode, I have:
- Battery is fully charged, and never a problem cranking
- 12v power to the ICM
- LED signal flashing from the PIP while cranking, which tells me the PIP is okay
- No LED signal from the ICM to the coil while cranking
- I have 12v ground at the ICM
- Will not start w/spout removed (PIP test)
- When I cycle the ignition key off and then on again, I get the LED signal from the ICM to the coil. Car will start, with or without spout connected (just dies again shortly).

I'm on my 4th TFI module, and my 2nd distributor (all Motorcraft), and even switched out a known working coil. Everything I see is pointing to a bad TFI module, but I'm having trouble believing that all these modules are bad.

I've thought about moving the TFI to another location, but I want to make sure of the problem before spending any more on parts.

Any troubleshooting assistance would be appreciated.

A little about the car:
1992 Notchback, newly rebuilt 5.0
10.5:1 forged pistons, Balanced rotating assembly
Motorsport GT40 X303 aluminum heads, professionally ported
F303 Cam w/1.72 roller rockers
Motorcraft distributor & Coil
3G Alternator w/4GA cable/fuse kit
255LPH Fuel pump, 24 lb/hr injectors
BBK 70MM TB, Pro-M 80mm Mass Air Meter
Cobra 13" front/11.65" rear disks, SN95 Master Cylinder & booster
AJE K member, SN95 A-Arms, 5-lug spindles/axles,
2004 Cobra power steering rack, MM Hybrid steering shaft
Tokiko adjustable struts/shocks
T-5, Cobra clutch, 3:73 gears, Motorsport Aluminum drive shaft
320 RWHP / 333 RWTQ
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,367
2,700
234
75
Dublin GA
lowendmac.com
You will have 12 volts both sides of the coil until the TFI turns on in response to the PIP pulse.

Did you use high quality thermal paste on the back of the TFI were it mounts to the distributor?
 

rbrown777

Member
Jul 22, 2017
13
1
13
Riverview, FL
I believe the thermal compound I used should work. I used Arctic MX-4. I spread it on about 1/16" thick across the surface of the module, smoothing it with a putty knife. Minimal amount squeezed out the sides when I tightened the screws. The original TFI had 2 blobs of thermal compound on the module, but I figured more contact across the module would be better.

EFI is new to me. I'm kind of old school with the carbs and such. I've been trying to come up to speed with this. I understand positive should be at both sides of the coil, until it gets the negative signal from the pip through the ICM.

That negative signal just doesn't happen when it goes into the 'no spark' mode. As soon as I cycle the ignition key off and then on again, it gets the correct signal and spark. It just doesn't last long before it dies again.

(BTW, your post about surging idle was very helpfull!)
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
18,828
6,212
193
polk county florida
This may sound silly but check your ignition switch under the dash on the steering column, the plug gets burnt and the switch can get sketchy, you need the torx bit for security screws, I always check them on every stang I deal with.
 

rbrown777

Member
Jul 22, 2017
13
1
13
Riverview, FL
Thanks Kartheif. I'm not great with wiring in general, but I've been reviewing wiring diagrams to try to figure how the ignition switch interacts with the whole process.

If I have constant 12v to the coil and distributor, even in the 'no spark' mode. I have a good LED flashing signal from the PIP at all times during cranking, just no ground signal from the ICM to the coil.

When i cycle the key off and then on again, I get the negative signal (LED flashing) to the coil again.

If I have 12v to the coil and distributor, along with good ground to the distributor, can you explain how the ignition switch might be a factor? I'm not disputing your suggestion, I just need to understand what's going on so I can get this resolved.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
18,828
6,212
193
polk county florida
Couldn't tell you, I just know the switch is susceptible to the connection getting over heated with intermittent failure, just something to check on the old cars, also grounds a very important to efi systems, make sure your grounds are present with clean connections, one ground that I have found to be missing one several stangs I encountered is the one behind the drivers head to the firewall and the one under the salt and pepper connections that is for the injector harness, good idea to check them too. There is another one between the battery and the solenoid, small black wire from negative batt cable to screw next to batt with another small black wire traveling down to a cylindrical connector then into the harness below, another is in the kick panel where the computer lives.