Have a 92' Camaro RS that doesn't seem to wanna stay running. Will start just fine(from Cold), will run for a minute or two and die......start again and die in 10 secs, then doesn't wanna start again on 3rd try. My first thought was IAC, did some reading and found some common symptoms with a faulty IAC, replaced that today and no change. Looking for some other thoughts or ideas. Thanks

 

What is the fuel pressure?

When it won't run, do you still have spark? Do the injectors spray fuel?

Connect a scan tool, see if there's something goofy in the sensor data.

 

@Schurkey I will check fuel pressure this weekend when i have time again to work on her, I think those are some other good things to check as well, thanks for the ideas. Ill post what i find out this weekend.

 

Replaced fuel pump and no luck, same symptom. Car starts(from cold) and runs a couple mins and dies, will start again and die, and will not start on third try. Im following some actual trouble shooting this time lol, and am led to believe there is an issue with no fuel. I can get it to fire on ether every time. I started looking at the Fuel Pump wiring and ran a jump wire from the Orange wire to Gray Wire at the Relay Connector and can hear the pump run. It seems to me that its running at cold start up but not running at normal operating temp. I did replace the Temp Sensor as i read somewhere this can send faulty info back to the ECU but nothing changed. Not sure what to check next if anyone has any ideas....

 

Test fuel pressure when it won't start.

Runs on ether. That verifies most of the ignition system.

It does not verify the part of the ignition module circuitry, or the wire harness that sends an RPM signal to the ECM; which turns on the fuel pump relay and fires the injectors. The module, or the wire harness could have an intermittent problem, or be outright faulty. The fuel pump primes, the engine runs, then stalls when the ECM fails to get an RPM signal from the ignition module. No RPM signal, no fuel pump relay and no injector spray.

Connect a scan tool, look for RPM readout from the computer when the engine cranks but won't re-start. If the computer shows RPM, the module and harness aren't the problem.

 

Wowza.........ok, First hooked up scanner ~ no codes. Not familiar with gaining RPM data from ECU with obd1, it could be my scanner doesn't have this feature or i just dont know how to access it. Next hooked up fuel pressure test before filter and got 11psi on the guage. Waited for it to die which it didn't disappoint....fuel pressure dropped to zero and stalls. Restart.....no pressure no start. cycle key no pressure no start.....restart....no pressure no start. cycle key hear prime...pressure comes back starts and stalls in bout 1 sec.....Restart....pressure shoots up car starts but will always stall after a sec or 2. Also not familiar with RPM data to the ECU playing a part in this, would like to hear how this system works from me and others if you have good knowledge on this. Thanks Schurkey

 

Do you have a scan tool or a "code reader"? They're not the same. A scan tool can read codes...and do so much more than just read codes.

The pickup coil in the distributor sends a signal to the ignition module, the module processes that signal, using it to time the sparks below 400 rpm, but also sending RPM information to the ECM. If the ECM does not get that RPM information, it turns the fuel pump relay off, so the fuel pressure drops to zero. It turns the injectors off, so they quit working. The engine gets no fuel, so it stalls. Above 400 rpm, the ECM adjusts the spark advance, so with no RPM information, you have no spark advance, poor power, poor fuel economy.

The pickup coil could be faulty, the ignition module could be faulty, the wire harness between module and ECM could be faulty, the ECM itself could be faulty. You need to know if the ECM has RPM data, because that would verify the pickup coil, the module, and the wire harness.

It might also be helpful to power the fuel pump by jumping the connector at the ALDL connector under the dash. I forget which terminal it is. If the engine runs good, you could have an intermittent fault in the fuel pump relay circuit that prevents the pump from running when needed.

 

Ok, I believe we are making progress. So i pulled cap off Distributor and found that 1 of the screws that hold down the ignition module was broken in two, I replaced the Ignition Module and the two screws that hold it down and everything seems better. What i think was happening is the Module was not being held down tight to the distributor where it seats and either making poor contact or it was in fact faulty all together. I say this because im assuming the Module must ground it self to the distributor which is why the bottom of the module it metal. Anyways it seems to run better now and adjusted the timing to 0* on the tab after disconnecting the advance wire. However i do notice now the Check engine light will come on a few seconds after starting and stay on through out the drive. I hook up my scanner and it says no DTC's found. Not sure why that is. Im gonna recheck timing again today just to verify and look over some stuff just to make sure everything is hooked up. I appreciate the help @Schurkey . I feel like we are getting close, Thanks.

 

SOMETHING is making the computer unhappy, which is why the light is getting turned on. A scan tool will find that.

 

I would agree.