1991
CAMARO
305 TBI AUTOMATIC


What occurred: I wanted to adjust the timing, for some reason it keeps getting itself out of timing, so what I did was loosen the distributor bolt and unplugged the EST cable and the car NO LONGER STARTED!!! it turned over and fired up then quickly died, after numerous attempts and hours later we left the car sit for a bit, I then sprayed starting fluid in the plenum and it started right up as if nothing had happen' I then let it warm up for about 3-4 minutes with the EST cable plugged in. I then unplugged it FIRED UP and instantly dies due to lack of fuel. I then plugged the EST cable in and it still didn't stay on idle, just kept turning, what the hell is wrong?

Potential Problems Checked out:
Fuel Pump Relay Working (SWAPPED the relay from the blower)
Checked E.C.M. fuse and FUEL PUMP fuse, both OK
MAP SENSOR GM NEW
INJECTORS ARE NEW REPLACED 10 MONTHS AGO
IGNITION COIL REPLACED 1 YEAR AGO AS WELL AS IGNITION CONTROL MODULE
NEW CAP AND ROTOR
VATS HAS BEEN DELETED FROM COMPUTER SO IT IS NOT A PROBLEM
OXYGEN SENSOR REPLACED 2 YEARS AGO

Symptoms:
INJECTORS DRIPPING FUEL INTO PLENUM
Injectors cutting off fuel, seems to be dripping fuel into plenum
SERVICE ENGINE LIGHT IS ON BUT HAS ALWAYS BEEN ON


What the hell else could I do?? I dont think it's the fuel pump since it's getting fuel (dripping) but then cutting off.

 

Dou you have a scanner?


Watch the registered RPM as you crank. Sounds like the ECM is not getting reference pulses.

 

what do you mean by reference pulses?

 

RPM signal from the ignition module.

It wont activate the fuel pump or injectors without it.

 

Hmm, I remember replacing that ignition module about 1 1/2 years ago I bought it from AUTOZONE could it go bad that quickly? no I do not have a scanner

 

Which brand did you buy?

I bought a GP sorenson one once that only lasted a few days.

It just seems strange how you were messing with timing and suddenly have a problem....

Does the fuel pumpl come on while cranking (may need a multimeter to see)


Do you have an oscilloscope by chance? The RPM signal from the module is a 5 volt square wave.

 

No I don't have an oscilloscope scope. I bought it Duralast I still have the original GM ignition control module, I replaced it because I thought it might of mal functioned while I had my vats problem, would you suggest putting that one (being the ORIGINAL GM) back on?

 

WTF, it turned on right now!!! I had the EST cable unplugged and it turned on as soon as I turned the ignition key I set the timing and turned off the car and then turned it back on and pointed the timing gun to the harmonic balancer and it showed the imprint beyond the degree line but the car sounded like it was timed so I unplugged the EST cable to time it back up and it WONT START NOW!!! WHAT GIVES!!! it seems if I wait more than 1 hour and try again it will start... whats going on??

 

will it crap out and stall if you let it run?


It wouldnt hurt to put the GM module back in.. It only takes 10 minutes.

Your problem sounds like it may be a loose wire or some other gremlin. Try the module though.

 

Ok I just replaced the IGNITION MODULE with the original GM one, still won't fire up... im stuck on what else I could do...? this car seems to start when ever it wants too

 

Thanks for your help, I was consulting one of my buddies from Texas who helped me find problems, we found it.

At first I measured the Resistance on the fuel pump by contacting my multimeter probes to the plug terminals from the fuel pump (located on top of the differential) I contacted the black with black and red with the grey wire that gave me a resistance of .909 K ohms which was weird. So I then grabbed a charger and connected it with some wires to the fuel pump plug and gave it a quick boost 12v I really couldn't hear the pump prime since the noise of the charger overcame the fuel pumps noise. I then was stumped and decided to remove the wires and plug it back up, keep in mind the rear of the camaro was up on jack stands and there was less than a quarter of gas remaining in the tank. I then asked a friend to go inside the car and turn the key in the ignition on the ON position to hear if the pump primes, I asked him to close the door so I would not hear that ugly default key sound. He turned it on and I HEARD THE PUMP PRIME!!!! I then commanded him to turn on the engine, it FIRED UP as if nothing was wrong!!!!! it stayed on IDLE I let it idle for some time to warm it up, I timed it, BOLTED the DISsy, PLUGGED EST CABLE BACK UP, and the car fired up nicely! The car being in my friends drive way, I asked if he had any fuel I could put in my tank, he said all I have is 103 Octane fuel,him that'll work so we poured some in until I got at least a quarter tank. So it had to be 1 of 2 things or both, Pump was stuck with little gas, or wiring was dirty!!??