2004 Impala Only starts on Starting Fluid, but runs fine after

[j cAT]

Originally Posted by bigj-dog

When I last had the car I didn't have a good enough diagram to know which wires were which at the injector harness plugin and I was under another time crunch, so I didn't have time to locate one. I just picked a couple of the wires and I did have a flickering led test light at a couple of those wires, but I don't remember which wires.

key on engine off both wires will have the 12 volts ...when cranking one wire will pulse this is the ground return injector wire that the PCM is grounding out so that the injector opens. pink is the feed wire most times should be..

[la1]

what about the air filter? maybe clogged, fuel filter ? I have a 3.4L and I had not changed my Fuel filter for over 80k miles when I finally did it was like I added 20hp to the car. make sure the throttle plate is closing all the way.

[bigj-dog]

Checked with air filter installed, or not, it's a K&N, which I'm not a big fan of. Fuel filter was replaced during this episode. I put my led test light on one of the computer controlled wires heading to an injector. It was hard to say for sure, but it sure looked like the light was flashing very quickly while it was running, but when I was trying to start it, the light appeared to be on steady. I didn't have time to pull the intake and install a noid light, so this is all I've got. I tried a PCM off Ebay. The guy said he programmed it for my VIN, but I tried to re-learn the security for 3 hours, but it never worked. So, I put the new one back in. Told them to try a BCM. That's really the only thing left.

[J-Ri]

If you're still working on this car, I'd check the Mass Air Flow sensor. Maybe it's not the starting fluid that's making it start, maybe it's taking the hose off the throttle body? MAFs will cause a no start (but it's weird that it would run good), having a K&N filter in there could have coated the MAF sensor with dirt and oil.

[bigj-dog]

Yeah, I cleaned the MAF, I tried starting it with the hose unplugged, with the air filter out, with the air box unhooked before I gave up. They took it to the dealer, who tried a new PCM, but no dice, and then many more hours of troubleshooting. They did finally find the problem, which was one of the wires going to the camshaft sensor in the intake valley. Of course, one of the few wires you can't see. I've had to repair those wires before while doing intake or head gasket jobs, but I never had one that had these symptoms. SOB. I just about took the upper intake off to put a noid light on an injector too. Could saved them $750 if I had. Too bad I'll never see the problem again, because I know just about all there is to know about it now. :-)