Long and drawn out, but I want to give detail...

Originally, I bought my car from an impound yard... thinking it might be a 91 or 92 .
As it turned out, it was actually an 84 with all the interior, newer panels, clips and doors, and L98 drive train all swapped over.
But no way to prove year beyond 91 or 92.

I have since junked the chassis because of massive structural issues, and swapped the running gear into a Mazda pickup.

I have a blast driving this when the weather is cool, or moderate temperatures, but I'm having drive-ability issues in the heat.
I don't have overheating issues with the cooling system in the summer, rather the engine just falls flat on its face and eventually stalls out.
At first, I thought symptoms pointed to the fuel pump cutting out, but I verified fuel pressure and ruled out the pump.

I have read through several threads, with similar issues, that found the ignition module to be at fault, so I replaced that, and have done so several times since.
Trying to relieve the module of excessive heat, I even modified a computer heatsinc and mounted it to the underside of the distributor.
That didn't seem to work, and I supposed the heatsinc to be heat soaking from the engine bay, causing continual module failures.
I modified another heatsinc and remotely mounted it in the cowl to provide cool ambient air to the fins, while a cutout in the cowl allowed me to mount the module directly to the heatsinc, but on the engine bay side for easy replacement.


I thought this finally cured the problem.

So I go on a road trip from Las Vegas to Kingman Arizona.
I was hoping for the best, but planned for an overheating module and took a cylinder of CO2 from work with me.
Sure enough, on the way back it lost power, sputtered, and eventually died out.
I took my CO2, ran a hose from the cylinder to the module, and opened the valve until the module began to frost up.
Tried to restart the engine... no dice!

Now I'm starting to think my pickup coil might be the problem, so through the vacant ignition module opening in the distributor cap, I hit the pickup coil with CO2 as well. Tried to restart the engine again... won't start.

At this point I could only think my ignition coil has failed, so I hit that with CO2 also... still won't start.

I sat on the side of the road for about a half hour trying to think of what else might be wrong. I had no ideas.
Just for kicks and giggles, I turned the key.
Lo and behold, I got life!

Okay, I finally got home after multiple stalling episodes during the next few hours. Yes, it took 5 hours to get home from a return trip that should have only taken 2... tops!

So now my truck sits in the driveway, and starts up and runs just fine.
A few days go by and the thought crosses my mind: Maybe the ECM is failing.
I pulled the ECM to get numbers from it so I could go get a replacement.
The sticker is GONE!

Now, I've searched through even more threads trying to figure out what computer came in a 91-92 L98 Formula.
Best I could come up with is this thread. Ecm replacement 7730/Are they specific to any one vehicle?
Post #3 outlines vehicles in which the 1227730 would have been used.
This applies to me, right?
So am I just a big dummy because it isn't sinking in, or am I just looking in the wrong place for a solution to my symptoms?

Any positive input is appreciated.

 

If you could post a picture of your ECM, that would help narrow it down.

Also:

If it is a MAF system, you will have 1227165 ECM (or equivalent, 16198259)

If it is an SD system (uses a MAP sensor), then you would have a 1227730 ECM, or equivalent, 16196344, 16198262)

The 1227165 uses two connectors, while the 1227730 uses 3 connectors.

That being said, it would be very rare for a failed ECM to work the way you are experiencing. Usually they work or they don't.

You have to verify, when you have the issue, if you lose spark, or fuel, or both. Keep in mind that the ignition system, will function (provided it's not a problem), without the ECM even in the vehicle, this is part of the limp home mode, where base timing is used and a very rudimentary fuel delivery calculation is used.

FWIW, I have NEVER EVER EVER EVER experienced any heat related issues affecting the ignition control modules in ANY of my GM or GM EFI equipped vehicles. I feel that the people that think this is an issue, are looking in the wrong place, because someone somewhere said it was an issue for them. Millions of GM vehicles are running to this day with the ignition control module mounted inside the distributor, and will continue to run that way. I have even gone so far as to mount a Delco ICM, by one drywall screw to the inner fender of my car, after an EFI conversion, and drove it that way for several months, including some trips over an hour each way, and NEVER experienced an issue. I converted to DIS, which is why I only used that set-up for several months, just wanted to the car up and running on the EFI and ran out of time to do the DIS side of it initially.

Make sure you have good grounds between the engine block, frame and the body of the vehicle, make sure voltage supplied to the components is good, especially at the point where you would experience the problems. Sometimes a poorly soldered wire , or even some corrosion within a wire can do funny things when it gets warm.

 

Okay, I have a speed density system, and the ECM uses 3 connectors, so I would assume I do, in fact, have the 1227730.
Is either the 16196344, or the 16198262 a weather tight ECM?

 

No, the "weather tight" ECM is the 1227727, 16197128 and 16198260.

The equivalent numbers are replacement or updated service numbers.