He has a 91 camaro with the 3.1l, he was on his way home the other day and it cut-off, so he assumed it was a fuel pump, he went out and bought a new one, and it still wouldn't run, so i sent him the check list for whether or not it was a relay, fuse, or the fuel pump, the one from
Tomp, he checked all of it and found a blown fuse and a wire that had been rubbing on something, so he fixed all of that and now the car will run fine in idle, but under a load it'll run for about 500' then shut off, he then checked the codes and it's throwing codes for MAP, O2, and fuel pressure regulator. Which one of these would most likely be the culprit. Or has the comp. been damaged by the wire that was shorting out that caused the fuse under the hood to blow.

 

Man thats a tough one. It might be a good idea to unhook the battery and reset the codes. The wire could have shorted ot everything. Those are all parts that will really effect the running of your car. Sorry am not much help.

 

The major problem here is that you guys have not done a complete diagnosis of the car. Since you need Fuel, Compression/Air, and Spark for the car to run, you need to find out which one you are losing. Unfortunatly, we can't even assume that you have proper compression or air flow.

Personally, from the sound of it, it sounds like he melted a cat and it's restricting the air flow through the engine. It's possible that under no load, the exhaust back pressure is low enough for the car to run and expel the burnt gases, but under load, when you are flowing much more air through the motor, the backpressure rises and suffocates the engine. It's a very common symptom of a partially plugged converter.

Although this is my thought, I suggest that you do make sure that you have proper fuel pressure after the vehicle quits running and also verify that you have spark getting to the end of the plug wires after it dies.

Without proper testing, your buddy will spend a lot of money replacing parts that don't need to be replaced, such as that fuel pump that he just wasted so much time doing because he didn't check the basics.

 

Well for an update. we cleared the codes, drove around for a few minutes, it still doing the same thing, by the way it has no cat on it, the cat had been taken off before he got it. also now only code showing is a code 34, we think we tracked it down to a bad ignition module. He's supposed to let me know this evening when he pics up a new one.