Reader Question: I have a 1996 Chevrolet Cavalier 2.4L. Over the past several weeks, it has had an intermittent no start problem. The problem typically arises when the vehicle is cold, and it is humid outside (although not always).
The engine cranks over fine, but it will not start. I have checked for fault codes, and when the engine is running, everything checks out okay. When the engine is not running (but the key is in ON position), it will not connect to the computer.
I have done a lot of research already, and initially suspected the PCM. I removed it, opened it up, and allowed it to thoroughly dry and re-sealed with a silicone gasket adhesive. Seemed to fix the problem for a few days, but then would not start again.
I have noticed the fuel pump does not run when the engine will not start. I have jumpered the relay, and the pump works fine. It just is not getting a signal to the relay to turn on (from the PCM I assume). Checking for spark is extremely difficult on this engine, so I have not done that yet.
I hope that you may be able to help me with my problem.
Do you have any suggestions?
These vehicles are notorious for weak fuel pumps. Could it just be a coincidence that the time it took for you to jumper the relay, the pump started to work?
Next time it will not start; have someone bang on the bottom of the fuel tank with a rubber hammer or their fist AS you crank the engine over. If it starts, you have a bad fuel pump.