Going down the check list...??
Going down the check list...?? So I had been having problems with my battery gauge falling down around 10-8 volts when i came to a stop or when the car would hit idle. So I pulled the battery had it checked it came back fine, next pulled the alternator and it also was fine. So now what?? other notes when i turn the key to accesories the gauge reads around 10 volts car starts fine and runs fine other than the volts fall from 13 to 10-8 range once at idle and when it does that the cars runs like a dog. sluggish mods listed in sig
I would have the alternator checked while in the car before I went any further. If it checks out fine in the car, then start looking elsewhere.
Could be corrossion, could be bad "excitor wire"...
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Could be corrossion, could be bad "excitor wire"...
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Drive it to an auto parts store and they'll go out and test it.
It takes all the wires and cables out of the loop when you test it off the car, if the alternator is good thats all you'll know. If you test it on the car with the engine running and you don't get a good reading, you'll pretty much know its a cable or wire.....which seems to be your problem anyway.
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It takes all the wires and cables out of the loop when you test it off the car, if the alternator is good thats all you'll know. If you test it on the car with the engine running and you don't get a good reading, you'll pretty much know its a cable or wire.....which seems to be your problem anyway.
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Last edited by LS6427; Aug 9, 2009 at 09:07 PM.
Well I guess I will b trying that later in the week. What would be the next step if its on the car and still passes the test? or from what you say it could still be the alt??
Going to replace excitor wire and get a new alt. where is a good place to get a cs130d 140amp alt. alternatorparts I cant get ahold of there number isnt working where else can I go
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From: Tulsa, OK
I'd just get a stock replacement. Unless you have some really extraordinary electrical loads, you're wasting your money on the 140 amp unit. You only need something like that if you're set up to run all the **** on a cop car. It's a lot like putting premium in an engine that doesn't require it, the car doesn't car, but you won't see any benefit at all.
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Verdad Gallardo I'd just get a stock replacement. Unless you have some really extraordinary electrical loads, you're wasting your money on the 140 amp unit. You only need something like that if you're set up to run all the **** on a cop car. It's a lot like putting premium in an engine that doesn't require it, the car doesn't car, but you won't see any benefit at all.
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No benefit whatsoever. The current that an alternator is capable of producing only comes into play in response to system demand. So, if all your loads total say, 80 amps, then that is all the alternator will supply. If demand drops, so does output. If demand increases, so does output...up to the limits of the alternator. If it stays at absolute max output for a really long time, it'll probably let the magic smoke out. If all you've done is upgraded the stereo a bit, but haven't gone nuts with amplifiers or things like that, then you're not taxing it particularly.
No benefit whatsoever. The current that an alternator is capable of producing only comes into play in response to system demand. So, if all your loads total say, 80 amps, then that is all the alternator will supply. If demand drops, so does output. If demand increases, so does output...up to the limits of the alternator. If it stays at absolute max output for a really long time, it'll probably let the magic smoke out. If all you've done is upgraded the stereo a bit, but haven't gone nuts with amplifiers or things like that, then you're not taxing it particularly.
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See what LS6427 had to say about the exciter wire, sounds like that's what your problem may be.
An alternator doesn't produce any juice at all just because it spins. It has to have a small voltage signal present from the battery to make it play, and that's what the exciter wire provides.
The car acts funny at a stop light because the voltage is so low. Computers don't like that very much.
An alternator doesn't produce any juice at all just because it spins. It has to have a small voltage signal present from the battery to make it play, and that's what the exciter wire provides.
The car acts funny at a stop light because the voltage is so low. Computers don't like that very much.
Heres is my worry. I go to auto store have them test it and they say it seems fine. once at idle it holds12-13 volts. so when I have them test it wont it be fine when its just sitting there? or will it show up that there is something up??
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If it's not getting proper excitation voltage, it won't show up as working properly. If it's an intermittent problem, you've got some troubleshooting to do, and it's gonna drive you up a wall in the process. Look at grounds, and look at every connection to the batt. and alt. just for starters.
Update Had battery checked was only 43% charged so i charged it over night. Had alt tested off the car and on the car passed both. when car is idling holds 13.8 volts. So I take it out for a drive after testing all and charging battery. Car runs good and volts hold at 13-14ish while driving, once I come to a stop they only differ when the car is running funny looking for an idle(grrrr) but once at idle all is good. The car was tuned last summer and seems to be having a hard time catching its idle(again), seems to search for it then finds it. if that makes sense in the tune?? or would the iac or tps have todo with that?
Update Alt check out fine by itself and on the car. Got the battery charged up. When I start the car the volt gauge sticks at 14-15. Once I drive the car for 10-15min it seems to slowley come down. Gets closer to 12-13 after driving for awhile then every now and then when I roll up to a light and come to a stop it drops down to 8-10 and the car acts as if it wants to die. ??
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I was having the same problem at the beggining of January earlier in the year. Couldn't figure it out so I put an Optima Red Top in the car and replaced the alternator, still acted funky so I replaced the PCM and reprogrammed it at work (A Chevy dealership, adn PCMs are covered under 8yr/80k warranty and made it by 2 months). Vehicle ran good for 2 months and then started blowing alternators once a week. I have replaced the positive battery cables to the starter adn alternator, replaced the PCM (twice), alternator 4 times, reqired the alternator to the PCM, added a ground wire from the battery to the block and I STILL blow alternators once a month. 16 GM certified techs at my dealership and no one can figure it out... Marinate on that one for a bit....
