FWNSBRD

I have a 91 pontiac firebird. The other day after a oil change the car does not run after shutting off the engine. You can drive the car all day and no ruff idling or any issues but once you park the car and turn off the iginition the car will not start for another 4 hours and then will run fine. I am having a heck of a time figuring this out. Everyone said fuel filter, that is replaced and now fuel pump but that is not making sense to me any suggestions. I tried seeing if there were any faults on the ecm and there were none.

manchesterbeast

does the starter turn at all? sometimes heat from headers can hurt the starter

thirdgen88

Could be an ignition module acting up... You need to do some diagnosis when the problem occurs.. Step one would be to verify that you have a distributor reference pulse during cranking.. Look for a purple/white wire coming off of the distributor, or at the ECM (B5 for TBI, BD8 for TPI/V6). Set your multimeter to AC voltage, and measure that wire (reference to ground). You should see somewhere around 2.5V during cranking. If you don't have that, then the ECM won't ever pulse the injectors, and you won't get any fuel. If you've got that, and you've got fuel pressure, you need to double check the basics...

EDIT: I guess we should clarify here.. It does crank, but it won't fire??

FWNSBRD

Well have it in for diagnostics at a shop but they have had it all day and can not come up with any solutions. I was told by a friends mechanic and not guess should have just replaced the ignition module like told and would have been on my way. So guess I wasted 100 dollars on diagnostic testing.

Yes the car wants to start, the engine will turn over just not getting fuel I guess and if that is the cause then great. Just does not really say anything in the Haynes manual about the ignition module about completely what it does.

Thanks for confirming what we suspected.