Hi all,
I have a 92 Firebird formula that has been running great. 305 TBI engine. High mileage however still runs strong. Of late the car won't start intermittently. It has a brand new fuel pump replaced 6 months ago which I can hear pressuring up. When it does start it starts right up but it seems once it even barely warms up is when it won't restart. I am thinking the fuel pump relay perhaps but that also was replace a year ago.

My question is, perhaps there is a sensor or something that is causing the engine not to fire... Being an old points and condenser guy car electronics are not my strong suit. Any help would be greatly appreciated.

Thanks
Ron

 

Do you hear the pump cycle even when it doesn't start? If it is see if your injectors are firing while cranking, if you're by yourself stick a piece of paper under the injectors to see if they have fuel on them. If they're working then check your spark. My off the cuff guess is your injectors aren't firing and that is usually a bad ignition control module.

 

Thanks for the reply... To answer your question, yes the pump cycles. It seems like the Throttle body injector is not working. Going to check the spark here in a bit, but I think you may be on the right track with the ignition control module.

Would this cause an intermittent problem such as it is doing???

Regards
Ron

 

Okay, checked the spark and Looks like that is the problem. I can smell gas so I believe the injectors in the TBI are working. Is the ignition control module possibly the issue and if so where is that located?

 

Yes it can be intermittent. I had a 92 RS 305 tbi that I bought a few years ago, that had an injector pulsing problem. Well the PO had changed his battery terminals for a top post and the fuel pump wire had become disconnected, so I fix it and it runs for a while and then It strands me with a pulsing problem. It still had spark so I didn't think it could be distributor related s I chased other things before changing the icm, however, that had no change. I had a good used distributor so I swapped it out and it fired right up, so maybe a bad pickup coil? I don't know, the distributor does control injector pulse so those are the things I would check first.

Ken

 

Check that you have power at the ignition coil. Also when you're cranking the engine is the tach bouncing or is the needle stationary?

 

The O'l girl has 207K on her so going to replace the cap, rotor and ICM. Which I haven't done yet since I bought her and I have put about 25K on her so I'll do that first for maintenance sake and go from there. Up till now she has been spot on dependable and I have taken very good care of the car since I have owned it as the body and interior are still in perfect shape. Since there were only 1017 of these made and it survived the cash for cars ordeal there are most likely not many left. That being said I will let you know the prognosis after I finish that. Thank you very much for all your help.

Ron

 

Just wanted to say thank you Ken for all your help... Put a new ICM in with an Accel cap and rotor and she is purring like a kitten again. Your help got me going in the right direction.

Regards
Ron

 

Cool man, glad to help

Ken.