Long story long. Driving around today (It was hot. In the mid 90's) and the car just died on me. No sputter then die, just died while driving. Got it off the road (luckly rolled it into a parking lot) and it cranked and cranked and no go. Had fuel pressure while cranking also. Engine temp was at 180* or below. Let it cool down for about 30 minutes then it fired up. Started driving it home and it bucked a few times then soon after, died again and again it wouldn't fire. Let it cool a little bit and it fired again. Managed to get it home and it died again right while I was pulling in the garage (lucky me). Again no fire until after it sat for a bit. When i got it fired in the garage, it died shortly after while idling in the garage. It has a 6AL with a Crane PS92 coil. Fuel pump is a Racetronix in tank 255 with direct wire setup and a holley inline booster pump from the 5176nos kit. So I swapped in my back up PCM and the car died again. Decided to bypass the 6AL and PS92 coil and hook up to my old stocker. Started and couldn't get it to die. Hooked up a back up PS92 coil and 6AL again and it wouldn't die. Put the original PS92 back in and it still wouldn't die. I didn't give the car cool down time, but worried that it cooled down just enough with the hood open to keep working. My theory is that either my 6AL may be getting hot. I won't rule out a fuel pump issue either cause my pressure seemed a bit low (32psi with vac line on) idling in the garage and seemed to fluxuate a bit from 30 to 34psi. It usually runs in the high 30's with the vac line and was pushing that while cranking also. No codes by the way. Any ideas?

Ken R.

 

i had the same problem and i live in vegas where is was like 110 degrees, then i changed my oil, spark plugs, wires, fuel filter, and oil filter, and it went away, about $100 fix

 

All that is brand new since i just dropped in my 383.

Ken.

 

I'd say ICM. If that sucker overheats it will shut the motor down. Sounds like you've got a classic case of it too with the heat up and die, cool off and start thing.

 

You mean PCM? If so, i already swapped in my backup as soon as i got it home and it still died just idling in the garage.

Ken

 

had a similar problem with a failing ICM.....hot = die....cool = OK...

 

ignition module

I had the same problem. I thought it was my brand new ignition module.Once it got hot it would shut off. It would cool down, start up, run, get hot die.

 

Think of what can suffer from excessive heat, and the Ignition Control Module is at the top of the list. Check Shoebox's Tech Pages for the way to space the ICM off the head.

The electronics in the Opti optical module would also be suspect.

Fuel pressure might be down if you're wearing down the battery/voltage by excessive cranking to start the car. But the fuel pump can also overheat.... with a large volume of fuel being recirculated through the fuel system on a hot day, it can pick up heat from the engine, or from the exhaust being too close to the fuel lines, and the pump may suffer. Does the fuel pressure look better when the car is started cold after sitting overnight?

Have you scanned it for codes?

 

No codes Fred. Pressure does drop somewhat after driving for long periods of time but still stays in the mid 30's while driving when it is down. PSI is normal after it's cooled down. Not just after an overnight sit, but back to normal even after sitting an hour or so. Don't suspect an opti issue since it's a brand new GM unit I put on during install and it has less then 900 miles on it. I've thought about the ignition module but didn't give it much thought, but after thinking about it, it is the original. But i've always though when those modules have gone bad, there dead period. At least thats what others have done in older GM's that i've owned where their under the distributor cap. I'll check out Shoeboxe's site too cause if I can keep it cooler by moding it, i'd rather do that. I've already picked up an new 6AL also. I wanted to before dropping in this new 383 just due to the fact that my current one is so old with a lot of miles and I didn't want it giving me issues trying to keep up with an even stronger setup. This just gave me an excuse now. Think i'll just go ahead and throw an ignition module in there along with it for good measure. Those are really the only items left in the ignition that aren't new, so I might as well put something fresh in there since everything else is. Thanks for all the input guys. Much appreciated.

Ken R.

 

ICM gets my vote as others have suggested. Spacing it off the head is simple and easy but if its already dying because of heat, you probably wont really keep it alive any longer unless you completely isolate it from the motor... such as putting the coil/ICM unit near the fender.

 

Just looked at the Shoebox mod for the ICM Fred, and actually, with the S-Trim in there, the coil mounts on the S-Trim's bracket and it actually puts the coil/ICM further away from the head then his mod. Think i'll put a new module in there anyway instead of waiting for it to totally fail, weather it's causing my issue or not. Still original and has some miles on it. Thanks.

Ken R.