I’ve had a rich start up condition for some time now on my TBI 88 Firebird and have tried to replace just about everything under the hood that might contribute to the black smoke on start up such as new TB, injectors, CTS, IAC, MAP, TPS, wires, plugs, cap, and rotor just to name a few. The plugs indicate a normal combustion so the problem only exists on warm startup conditions. I am at a loss on what else I should try to solve this problem and am looking for any other suggestions. I have also tried to lower the FP to 9 psi but encounter bog on acceleration and the car still runs rich on startup. Does anyone else have this problem with EFI I thought that only carbs would behave this way? Anyways thanks for any suggestions you can provide.

 

O2 sensor maybe bad?

 

No not the O2, matter of fact when I replaced it I lost about 1 MPG. Hows that for trying to get better gas mileage? Could pressure be built up in the tank enough to cause this type of problem? This problem only happens at startup so only the systems to get the car running are at fault I belive. Thanks for the reply keep them coming.