Finally got the Z out of her winter storage cocoon over the weekend, and after a quick jump start left it to idle and charge the battery up while I treated tires, rims, etc to a good polish. After maybe 15 minutes the car stalled out. Turn the key, no juice. So I jumped it again, and this time the car stalled out as soon as I removed the cables.

Ok, I think... bad alternator. No worries, quick trip to the auto parts store (3rd trip that day, it was a fun one) and 15 minutes later, new alt installed, jumped, idle to charge, car stalls out in 5 minutes, no juice. So I pull a battery out of my mud truck which I know is good, put that in the car and start diagnosing charging issues.

Alternator puts out 14.22v when first started, and as the car idles it slowly drops, after 2-3 minutes it was putting out 13.8v. Pushing on the trottle doesn't increase the juice at all. There isn't any burn through on the alternator wires, though oddly the lead to the battery cable is bare about 1" before the junction to the battery cable, almost like the factory insulation shurnk with age, because it's a clean factory cut on the insulation.

I searched and found folks reporting alternator charging issues being related to fan fuse issues, but my fans kick on, and the fuse is good. Two of my tenants are good mechanics, and all 3 of us are stumped, so I'm wondering if the camaro experts would have any insight.

As far as I know, everything ran fine when it was put into storage, and I see no evidence of mice or anything getting into the car to muck things up as they tend to do.

 

bad battery if you didnt keep it on a trickle charge, they dont like to come back. 13.8v is good after its run for a little while.

 

Ok, I can buy the battery being dead, that would explain it not taking a charge, but not the car cutting out on idle. Should be able to run the car without a battery even in it.

 

you cant run efi cars on just the alt, the battery is a regulator as well as storage and you can damage your components if you try to run it that way. if your battery has a dead cell(voltage just sitting there will be about 10v) the alt will be struggling just to try to charge that let alone run the engine

 

Cool, thanks for the feedback and info. I did put a known good battery in the car and just thought 13.8v was too low. If I put the air on max it'll drop down to 12.8v at idle, which will bump up to 13.2 if you rev it to 2500. I'm just used to a car running stable at 14.4v.

 

over 14v for a long time seems like there is something wrong with whatever car is doing that. your camaro seems fine loaded down at idle it will drop down, and would be a little worse if you had any aftermarket equipment.