I am trying to help someone out with their car and I am stumped. The car is a 1989 Pontiac Firebird GTA SE with 350 motor and an automatic transmission.
When the engine is cold the car starts and runs perfectly. If you shut it down when it is hot it is impossible to restart. If you wait awhile for the car to cool off it will eventually be able to start again. We believe it will not restart as soon as it goes into closed loop.
There are no faulty codes. All of the sensors values are ok (checked with AutoXRay scanner), at cold and at hot. The fuel pressure is good also. The starter turns, ignition is ok, and fuel is ok.
This car now has a new ECM, ignition module, spark plugs distributor cap and rotor, and a replacement Eprom. Oddly enough, the car starts fine hot or cold with a 1986 305ci Trans Am (AUM 3236) it just doesn't run too well due to injector and fuel pressure differences.
We think the replacement Eprom may not be any good since it will start fine with the 86 prom. We would like to see if someone has a spare or would mind swapping one just to try it out. The ECM number is 1227165. The Eprom number is APYU 3516 (AUJM 0580 works also). A 1989 Camaro is the same.
If you have any other ideas that would help so please send them our way.