Alternator bad?

[majette]

hi all. my 84 won't charge at idle, will charge if the engine is revved. some slight play in the belt but it should not be enough to affect it or could it be the culprit?

[Phoenix]

Try replacing and tightening the belt. Check that there isnt oil dripping onto the belt.

I had that problem when I first got my car. There was nothing wrong with the alternator, just the belt.

[Keyfoo]

I had same problem, check wires to alt . On mine main wire was lose in the crimped part of the connecter. Didnt notice untill after buying new alt. Seen same problem on my buddies 82supra.

[Digilog]

I could be wrong here but I didn't think alternators charged at idle they just maintained charge and don't start actually charging till they get more revs?

Carl

[majette]

here's more detail. if i drive it, it will want to die at idle unless the revs are up. at night the lights dim at idle, if i do not rev it it will shut off, i rev it and the lights brighten up. i still don't think its charging cause the next morning it will need a jump.

[Superium]

sounds like you blew the voltage regulator on the alternator. Take it out and get it tested for free at auto zone. They can identify if its the alternator all together or just the regulator. Make sure your battery is not leaking or bloating and check the voltage on both the battery and alternator as well.

[falconindy]

was the alternator replaced at any point? if it has been, check the brand. ac delco (very common replacement) alts wont charge at idle.

[majette]

new battery, alt looks to be original (only had the car a few months). i will have someone take it off and have it checked. (i do car audio, not mechanics)

[Phoenix]

here's more detail. if i drive it, it will want to die at idle unless the revs are up. at night the lights dim at idle, if i do not rev it it will shut off, i rev it and the lights brighten up. i still don't think its charging cause the next morning it will need a jump.

Still sounds exactly like the problem I had. You probably should change the belt ANYWAY. Thet are cheap. Tighten it up good, and see if that fixes it. If not, you've just done some routine maintainance.

BTW. If its's the alternator you don't necessarily need a new one. Most common alternator problem is worn contacts. Replace the brushes. It's very doable and they cost pennies. :wink:

EDIT: someone suggested checking and cleaning the electrical connections. That's always good advice. 8)

[falconindy]

or...if you wanna replace it, get an 80 amp unit from a 90-92 mk3 slushbox turbo. pretty easy upgrade, and you can buy the alt for 50 bux.

[Phoenix]

or...if you wanna replace it, get an 80 amp unit from a 90-92 mk3 slushbox turbo. pretty easy upgrade, and you can buy the alt for 50 bux.

Yeah! if you've got the money you should definately do that! 8)

But, if you're strapped for cash then you probably could fix this yourself for cheap

[link973812]

Check your connections to your battery....if they are loose it'll cause all sorts of problems.

[majette]

give me more info on this alternator upgrade. is it from a 90-92 Supra Turbo manual trans model? is it a direct replacement, mounting and wiring connection? who sells it for 50.00? i would do that instead of getting this one rebuilt as i want to put in a nice system and the wimpy alt that is in there now will limit me.

[Phoenix]

give me more info on this alternator upgrade. is it from a 90-92 Supra Turbo manual trans model? is it a direct replacement, mounting and wiring connection? who sells it for 50.00? i would do that instead of getting this one rebuilt as i want to put in a nice system and the wimpy alt that is in there now will limit me.

The 80 amp alternator is a fairly common mod. There's a ton already in the database about it. Just use search :wink: You get them for fifty at a junkyard. Don't pay any more than that. Good luck.