1993 Cavalier 2.2L that I race on dirt tracks--last race out it started cutting out pretty significantly, curiously was only doing it in the corners (our track is a high-banked 1/3 mile) but not on the straights. After the race I found that the battery was dead.

Checked both the alternator and battery, both were okay. So it sounds like a loose ground to me. Problem is, I feel like I'm looking for a needle in a haystack looking for it. I looked everything over, I could not find any loose wires or anything obviously wrong except for the following: (1) the ECM had fallen out of its bracket and was laying against the passenger-side floor pan; and (2) the ceramic insulator around the wire on the O2 sensor had cracked, and the O2 sensor was very loose (I have a Pacesetter header, and the sensor was essentially just resting loose in the opening for it).

So, two questions: (1) are there any places in particular I should look for a loose ground? and (2) I wouldn't think either the computer making contact with the floor pan, or the loose O2 sensor would cause cutting out and drain the battery, but I could be wrong?

Forgot to add, I obviously bolted the computer back in where it is supposed to go (it was just laying there, but no wiring harness had come loose or anything), and I put a new O2 sensor in.

What I am worried about, though, is that I will not really get to see if it is fixed until the next race, and I only race every three or four weeks. I just want to make sure I have covered everything possible before taking it back out.

Only a couple major ones i could think of..

Grounds are the numbers that have a G in front of them

How do you know that the alternator is working? If your battery died while it was running, the alt is probably dead. The alternator grounds itself right to the bracket and thus the engine. So if you're maintaining electrical power enough to run the car off the battery til it's dead (which you obviously were) then I don't think it's a grounding issue.





www.gmscf.com

Thanks much for the diagrams. I know I checked the first one, behind the battery; I will make sure I checked the second on the starter.

I agree, initially I thought it was the alternator, but I took both the alternator and battery to Auto Zone to test and both checked out okay.

If the battery was dead and the car runs...the alternator must work since that is what your running with. I'd question the diagnositcs of the 'good battery' you say you have. I'd be willing to bet it is indeed bad. Besides that, most all batteries, once dead never recover fully. If you can get one cheap, I'd replace it.


"Never argue with an idiot. They'll drag you down to their level, then beat you with experience!" -Anonymous

Dumb question, how much gas did you have in it?

Not a dumb question, is it the original fuel pump?

The dumb question isn't so dumb, originally I thought it might be low fuel b/c it was only cutting out in the corners (ie, on an incline), and I didn't have much gas in it b/c the car was loose in hot laps and I wanted to keep rear end weight down. But I filled the fuel tank up for the feature and it was still doing it.

Fuel pump--have no idea if it is the original. But I am leaning away from that b/c it is only doing it in the corners and b/c of the battery getting drained.