Join Date: May 2011
Location: Bowling Green, MO
Ok, I will start at the beginning. I bought a 1992 Camaro Z28 with a 5.7 TPI. When I bought the car the person who I bought it from stated that it needed a new fuel pump and the car should be fine. He also said that he had the cat converters removed because they were bad.
At home I began with a visual inspection of the car. It has aftermarket headers, the person had removed the cat converters with a very poorly welded in straight pipe.
I check the fuel pressure it is perfectly fine, but the car turns over well, but does not start. I then check the spark plugs and wires. There were two types of plugs in the car and both were wrong, and the wires were two different types and both were old. I changed the plugs and wires with new ones. I used E3 plugs and factory wires. I had to remove the headers to get to all of the plugs, while the headers were off I discovered the positive battery cable going to the starter was nearly burned in two from the headers. I replaced the battery cable. After that was done, the car started right up with no issues. The fuel pressure is right at 40psi. I only let it run for a few moments because not all of the smog system was hooked up. I then reattached all of the smog system and put on the muffler which had been removed.
Again the cart started up with no problems, but shortly after starting the car began to stumble when I tried to rev the motor. In fact it was bad enough that the motor would spark knock and die. When the engine was running there was a sound of a very large vacuum leak. There is a tube that runs from the smog system to the cat converters I figured that this vacuum leak was the problem. I plugged that tube with a bolt. Still no change.
I then removed the snorkel for the air cleaner system and it was obvious that the air leak sound was coming from the air plenum. Specifically the IAC area. I removed the IAC and cleaned the carbon from it and reinstalled it, but no change. I removed the EGR valve and checked it. It is not sticking and it was not overly dirty. Still no change. The Map sensor that was on it had a crack in the top of it, I changed it and the problem has gotten worse.
At this point the car will start fine, and the vacuum sound at the IAC is minimal, but as the car warms up the vacuum sound get remarkably worse, and the car begins to stumble on its own. When cold the car will rev just fine, but only for a few minutes then it begins to choke its self out. When I press the accelerator it will die. When the car dies it will start right up.When the car is choking out the fuel pressure stays right at 40, or just below. I have not taken it to the shop to get put on a diagnostic machine, so I don't know of any trouble codes. There are NO check engine lights at all. Please help
1968 Camaro, 1992 Camaro Z28 5.7