first of all, thank you John for taking the time to type out such a thorough response. as for the extra information on the build, the motor was broken in using conventional oil with zinc additive at first, ran her for roughly 50 very nice easy miles then changed oil, ran conventional oil again (was told that conventional oil is better for making sure rings seat) anyways, after changing the oil again we ran her through some rpm cycles, not very aggressive on the throttle at all, but slowly gave the motor some rpm and let the rpms wind down, took it easy for roughly 500 miles, changed oil again and made a few pulls, mostly easy driving, then after around total miles, changed oil again. the engine got a 600-700 mile break in. she runs 9.0:1 compression, the cam specs are .555/.558 lift 224/220 @ .050, 111 lobe separation. I am currently running regular automate 104 spark plugs (although I normally try and run at least an autolite platinum or better).I haven't tried making any pulls with the chip on tune 2 or 3, may have to try that and see what happens. when I put the chip on tune 0 (assuming that would be the stock a9l tuning, no it doesn't really run. I have checked the timing and it is set at 14*, have not tried unplugging the mass air meter yet, I have a new air filter on the way as I am not totally satisfied with its current condition. I am running gt40p heads that have bigger valves and have been ported. the heads were tested on a flow bench to 239 cfm@ .500 lift, the springs I used are Alex's parts springs (I double and triple checked with ed Curtis that the springs and cam would work together, which he said they would), admittedly I am not very handy with diagnosing problems like this, I don't even own a scan tool for etc-iv. I personally am growing more and more suspicious that I possibly am having an ignition switch go out, went to the car yesterday afternoon and she wouldn't start at all..went to her today now and she cracked right off.[/QUOTE
Hi! Good to hear from you. There’s a few things that I think may help you out- and NO PROBLEM! Correct with the Oil and seating Rings. Never use Synthetic initially-or they may glaze over- especially the harder ‘Moly’ Piston Rings. Btw-Did you you use Heat Sink Compound when you reinstalled the Distributor TFI Module(s)? It’s imperative, the Distributor IS the Heat Sink for that Module. So it needs that Compound to Transfer heat to the Distributor- and dissipate it. Or it will cook! There is also a necessity to have a solid Block to Distributor Ground- (Grounds are a BIG issue). Sensors are reverse of common thought. One would think Power would be Switched on Sensors- Ground always Solid. In actuality- the GROUND is what the EEC switches on/off, Power is always present, or generated (Such as 02 Sensors). There’s a few good TFI diagrams, Sensors, Ignition Switch, etc. i’ll post It for you. Actron makes an OBD-1&2 tester in one 30$ +/- Very good to have. Plugs in to the Diagnostic Connector- gives the Code# and the description. The Other option is old school, jumper wire across the correct Diagnostic Connector pins, it will illuminate the Dash Check engine light- it flashes and you visually record the flash counts-it gives you the multi digit Code, you look up the #. Ignition Switch- replace it, I’m still thinking the issue is elsewhere- but if it’s not right- replace it for sure! No loose ends. Go to RockAuto. Com. You will find great prices for quality Parts, there.
If you have Codes in the EEC, you need to read them, then DUMP them. If they’re Codes there- it Can affect the Grounds for certain Sensors, may malfunction. It’s a Grey Connector right on the Drivers side engine compartment- hangs off the Firewall. All you need is a 5$ Test light. A Haynes (Not Owner’s- Technical) Technical Manual is handy, Lots of info to familiarize yourself with things.
If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars. (Yours is NOT this, unless it has the California Emissions Sticker on the Radiator support- you have a CEL (Check Engine Light)that works, note that a CEL light Flashing when Accelerating (About 1.5 second intervals- and stops flashing when not accelerating). If occurs while accelerating this means you have a Cylinder missing. Spark issue. This is the same for an OBD-1 (your 91’ LX) or (82’GT to 1995 GT’s) and OBD-2 (1996-up GT/LX’s). Good info below. I’ll add a few things that are missing, but it’s pretty informative. Take a read...
89 through 95 cars have a working Check Engine Dash light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems
Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10
Alternate methods:
For those who are intimidated by all the wires & connections, see
Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see
Equus Digital Ford Code Reader (3145) Equus - Digital Ford Code Reader 3145.
It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.
The TFI module mounted on the distributor is usually the culprit for a high speed miss on a warm engine. —>If the problem does not occur when the engine is cold,<~~~(?)the TFI module is definitely suspect. You may need a special socket to remove the TFI module, but most auto parts stores will have one for $5-$7.
Be sure to use plenty of the heat sink grease on the new TFI and clean the old grease off the distributor.
See
Automotive Tools Specialty | Auto Mechanic & Technician Diagnostic, Testing Equipment | Thexton
DVOM= Digital Volt/Ohm Meter, a Basic Meter for measuring Ac or Dc Volts, Ohms, some measure Amperage (Limited to a certain amount of Amps), Continuity (Some Audible). 2 leads Red/Black- a Rotary selector in Center to measure what you are seeking. If you’re looking for Ohms (Resistance) select OHMS close to what you are expecting- most are ‘Auto ranging’ meaning if you select a different amount than you need, it will read what’s there. Only thing you want to remember using one is- you are reading DC- rotate the knob so it points to DC, or AC to AC. They are much more forgiving these days- than 10-15yrs ago- no
worries. Look at the Manual. Just ensure that if you buy one that you have to plug leads in to the Meter- plug Red into ‘Voltage’ and Black into ‘Common’ (Usually have lead Colors next to them). The other hole is for measuring Series Amperage, and will SAY “AMPS” next to it- and the Maximum amount of AMPS you can read- I.e. “10 AMPS MAX!!” Read the book if you want to do that, all a little bit different, shouldn’t need to read “Amps”using one on the Car. Only likely DC Volts, or Ohms, or Audible Continuity (like checking a disconnected wire). NEVER have the Plug into the “AMPS” hole, and read Voltage, or Vise versa. Again- they are pretty safe in that area now- but NEVER ASSUME THAT! Plug Red and Black Wires into the 2 Holes like I said, only. You’ll likely never need the other. Questions- ? read the Manual- best bet! Ask the Manager of the Store to show you how to use it. Remember one thing- Measure “Ohms” only on items that are listed- a small amount of current flows into anything you measure Ohms or Resistance on. It won’t hurt you- won’t even feel it- but into a wire/wires or pins going through/into the Computer- or an 02 Sensor- you can possibly damage it. So, just read across what are reliable sources. Which is why I suggested a ‘Shop Manual’. You can find a Service Tech Manual for your Car likely on EBay. A little easier to understand Manual- a Haynes, AutoZone or RockAuto cheaper. A good set of tools to have- A DVOM like this- can get a real simple one for 10-15$, a Test light is a useful tool, and an OBD-1 Meter to read Codes. Tech.Manual on your Car. You need to read verify values, pull Codes- the most simple, accurate way. Then dump them. You may also be able to dump the EEC Codes simply by disconnecting the Battery for 30-45 Minutes- only way it won’t clear them is if it still has the same issue. Gap your Plugs at 0.052-0.056, running Motorcrafts- right? Good luck! Have another diagram- phone’s dying, I’ll get it to you today- tonite.
diagram courtesy of Tmoss & Stang&2Birds