1993 LX 5.0 dies after ignition parts replacement

I removed the smog pump a few years ago so there are some electrical connections that are disconnected. I'm assuming the constant 12v to ECU is all the time regardless if the key is on or off, correct? And whereabouts would I check for constant 12v at the ECM? Also to add, the ECM power relay does activate when key is turned on
Did you adjust the timing on the car when you swapped out the tfi again ? Car not going to start if the timing not in right ball park.
 
I am still going with the ECU has :poo: the bed but at this point I think you have entered the realm of the one and only..."Cranks OK, but No Start Checklist for Fuel Injected Mustangs". If you have not already you need to work your way through this checklist and DO NOT skip around. Work through the list methodically.

 
I am still going with the ECU has :poo: the bed but at this point I think you have entered the realm of the one and only..."Cranks OK, but No Start Checklist for Fuel Injected Mustangs". If you have not already you need to work your way through this checklist and DO NOT skip around. Work through the list methodically.

At last a reasonable voice, I mean all the parts replacement is just a 'hope I get lucky' form of diagnosis.
This crap drives me crazy, it's not much different than the old school diagnostic just different tools.
The 'cranks but no start checklist' is the standard for our cars if you're not utilizing it then you're chasing a fart in a windstorm.
First, like the checklist says, try starting fluid, that will tell you spark or no spark, move on from there, do the next step, has worked for years.
 
Okay here are the codes:

Code 10 - Separator between KOEO and KOER tests

Code 11 - Test Passed.

Code 15 - No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test Failure)

This can be from an aftermarket chip plugged into the ECU but you have stated that you do not have one. I would start by making sure you are getting a constant 12V+ to the ECU. If that is confirmed then my guess is that the ECU has problems internally.


Code 85 - Canister Purge solenoid failure

Do you have a charcoal canister and purge solenoid? Is the solenoid connected to the wiring harness? Also, walked away from the computer and then remembered that you can get a Code 15 if you disconnected the battery at some point and have not cleared the codes since then. Really easy way to clear the codes if your code scanner does not have the ability to do it is as follows:

Ok so I checked for voltage at pin 1 at the ECU and there is 12v with key on and off and 10v while cranking. I checked voltage and resistances at the TFI connector and wrote them down on a diagram which I will attach
 

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Basic things that you need to provide in a thread like this.
Stick or Auto?
Mods
Any codes?
What were the name brand of the parts that you used to replace the existing parts and why did you replace them?

The check engine light (CEL) only illuminates for emissions related codes. There can be codes and no CEL so if you have not scanned for codes please do so.
I had a similar problem on my 93 Gt 5 speed, found out that when it warmed up I got back fires surging and all that you described. I replaced all the things you did except the map and then replaced the distributor assembly and that was the problem. Internal electrical part cost about $20 to replace- I found out later- but the new distributor works great cost about $130
 
The OP just needs to stop throwing parts at it and work through the list.
Ok so I believe it is the ECM. I checked resistance between the ignition ground circuit from the TFI plug to chassis ground and the ECM case and got 5k ohms of resistance. Then I went from TFI ignition ground to pin 16 on the ECM and got 0.5 ohms of resistance. Then I went from ignition ground pin 16 on the ECM to chassis ground and still got 5k ohms of resistance. I checked ECM ground to chassis ground and got 1 ohm of resistance.
 
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We will all pray for the resurrection of your ECU.
So at this point I'm assuming there is something wrong with the ignition ground circuit within the ECU board. Also I believe that the ECU is a remanufactured ford ECU
 

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I made my own bracket for the footwell under the carpet.
I mean, you can see it's there; it's not hiding from anyone but... Racecar :burnout:


:jester:
My problem is that it is a reman ECM and the sticker on it says A9L which is for a V8 5 speed and my wifes car is a V8 Automatic which needs the A9P but unsure of the calibration
 
Open up the ECU and let's see the capacitors....
So I circled the capacitors. The one circled in red has 37k ohms of resistance. The one circled in blue has 622 ohms of resistance. The one circled in yellow has 5.6k ohms of resistance. Now in the close up photo of the backside of the ECM, the object I have circled in red has 3.5k ohms of resistance
 

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