when im at idle my car puts out about 11 volts, with the headlights on its only producing 10 volts or so, It has a new alternator, cause the other one had a bad voltage regulator and the battery kept going dead, However when its reved up it goes up to about 12-13 volts. But when my car is first started in the morning it runs rough and backfires until its warmed up, I can also hear the fuel pump running while im driving my car, its very noisy.

matthew

your new alt and/or battery are bad or have major wiring problems.

yes, low volt will screw up every thing. have the system tested. many places can roll a cart up to the car and test it on the spot.

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11-Sept-01, The day the world as we knew it ended.

Yup, Low volts will really give you gremlins. There's enough there to run(barely) but not the kind of voltage your ignition and everything else needs to run right. Could be alt or the internal regulator, could even be crud on junction block by battery or some other wiring..Hard to say...Just start checking stuff

Yep Matthew, low volts can cause anything from a screwy acting radio to an engine missfire. The system is designed to run on a min of 12.6v DC. Check voltage at the battery with a voltmeter. The volt gauges on the car can be WAY off. Good luck!

Phil

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GTDude
OVER 25 years GM experience

I concur, low voltage will mess you up. At idle with no headlights on you should have 13-14.5 volts or so at the battery, if you don't you have a battery or alternator problem or a huge drain on the system somewhere. Make sure you have a good voltmeter that will distinguish between 10 and 12 volts.

ill get hte volt meter on it today, I was going by the aux gauge pod gauge, at idle with all hte lights off and nothing but the car running, it sits at 10.5-11 volts, when reved upto 3k or so it goes to 13 volts. When the lights and stereo and AC are on, it never goes above 11 volts.

even at 5k rpm.

matthew

MAtthew, check your battery voltage with the car turned off. It may be that your battery is somewhat discharged/or a dead cell. Some of today's alternators only start charging when they see 12V from the battery! My bet is a dead cell!
Sandy

brand new battery, brand new alternator (also the battery was the most expensive one i could find that still fit in the factory location) i think its 950 cranking amps and 700 cold cranking amps with a 80 minute reserve capacity. I purchased a 94 amp alternator also i run a large stereo in the car, it pulls 70-100 amps of current, so i unhooked the stereo and it made no difference.

(im currently only pulling about 50 amps from the stereo when its at max)

matthew

I have a question about HIGH voltage. My voltmeter bounces in and out of the red region on the aux gauge. At startup, the idiot light is on sayin its not charging, then as soon as I tap the gas pedal, it shoots up to the red. COuld this have anything to do with why I keep blowin brake fuses every 3 days randomly?? Also, could I have this tested too, like that low volt thign??

Check the connection ( red ) wire going to altinator. There is a " Y " connection about half way back down from alt. I had same type of prob. and found bad connection at " Y " I didn't know it was there,found it while installing a new connector to alt.( plug ) You will have to strip back the black flex cover to see it.

Good luck

I recently had a similar problem started to pull out my hair, after checking every thing I eventually changed my new Bosch plugs to some stock ones and the car revved like a Jewel. ......So try changing your plugs..that could be the problem

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YES low voltage can screw up everything. Heres an interesting story. I have an 85 fiero gt.about 2 months ago the volts on my rally cluster (custom install) when down to 10 or so and would build with revs. the car ran funny til it warmed up. then it wouldnt start i had to push start it.so i pushed started it for likea month until i was driving one day and i smelled smoke and the car died. I pulled over opened the backa nd relized i was burning a wire in the wiring harness.I checked my book figure out this wasa ground wire for the ecm. i d/ced the battery and though about it for a week. then i did some checking and fiured a positive unfused wire must be shorting becasue not only that greound wire but my parking brake cable and all ground wires were melting. I figured out that it was the pos. line to the alternator and the alt. was shorting out internally. so i replaced the alternator. Car started but still had low volts. the nest day i saw that same wire in the wireing harness ( which i reran and replaced) smoking again. It seemed to me like the whole car was trying to run the neg though all the small ground cables and not the main one. i had cleaned and checked my ground cable earlier and it look fine but i deced i couldnt think of anythign else so i gave it a shot and rep[laced my main ground cable fromt he battery. PESTO! everythign worked great. car ran fine now i have 14.5 volts all the time. the morle of this story is that bad ground cabel that looked innocent blew my alternator and part of my wiring harness and gave me a month of problems. if that not ruining everyhting i dont know what is!
ALEX