Keeps blowing fuse, alt bad?
09-17-2010, 08:08 PM
#1
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Car: 1982+1988 Z28 Camaros
Engine: 1982=350 carb 1988=383 Carb
Transmission: 1982=4 speed T-10 1988=6 speed T56
Axle/Gears: 1982=stock
Keeps blowing fuse, alt bad?
Ok here's the history. My fuel pump quite on me one day while driving. Tested fuel pump with direct hot wire, works fine. Found out the problem was the fuse up in the engine bay next to battery was blown, replaced it but it blew the moment the new one was seated. Took it to a shop to have the short (most likely the cause) traced down, after four hours they decided the short was in the alternator. It seemed like that was the issue, because running only on battery power with alternator disconnected the car ran just fine and I drove it home.
Replaced the alternator under warranty, fired it up and it ran like a champ. Let it idle in the driveway for five to ten mins under my supervision. Took it out for a spin to further test it, it died again just on the on ramp to the freeway not even a full mile from my house.
Looked at the engine bay fuse again, blown. Replaced it, blows again immediately. Did my alternator short out again? Or is there some other wiring short that is causing my alternator to short, or is it even in the alternator? The voltage gauge (Autometer, so I trust it) says with the first "bad" alt and this new alt, 14 volts at idle and speed.
I am really at a loss for ideas about where to start here, any suggestions or experience with such a problem?
Replaced the alternator under warranty, fired it up and it ran like a champ. Let it idle in the driveway for five to ten mins under my supervision. Took it out for a spin to further test it, it died again just on the on ramp to the freeway not even a full mile from my house.
Looked at the engine bay fuse again, blown. Replaced it, blows again immediately. Did my alternator short out again? Or is there some other wiring short that is causing my alternator to short, or is it even in the alternator? The voltage gauge (Autometer, so I trust it) says with the first "bad" alt and this new alt, 14 volts at idle and speed.
I am really at a loss for ideas about where to start here, any suggestions or experience with such a problem?
09-17-2010, 09:43 PM
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Car: 88 (SOLD) & 90 Iroc convertibles
Engine: 5.0 TPI, 5.0 TPI
Transmission: 5 speed & auto
Axle/Gears: 3.08 & 2.73
Re: Keeps blowing fuse, alt bad?
what color was the wire on which the fuse went
09-17-2010, 09:52 PM
#3
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Car: 1982+1988 Z28 Camaros
Engine: 1982=350 carb 1988=383 Carb
Transmission: 1982=4 speed T-10 1988=6 speed T56
Axle/Gears: 1982=stock
Re: Keeps blowing fuse, alt bad?
Red I believe. There's only one fuse (and pair of wires that utilize it) by the battery, so it would be hard to mistake the one I'm talking about.
09-17-2010, 10:09 PM
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Car: 88 (SOLD) & 90 Iroc convertibles
Engine: 5.0 TPI, 5.0 TPI
Transmission: 5 speed & auto
Axle/Gears: 3.08 & 2.73
Re: Keeps blowing fuse, alt bad?
Did you follow the wire to see where it leads to . If fuse blows right away it sounds like a short ...wire might be nicked or pinched or bad connector(check connector at altenator GM has replacement connector if required I had to replace mine)
09-18-2010, 02:31 PM
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Car: White 1987 IROC-Z
Engine: 305 TPI LB9, 215 HP
Transmission: Borg-Warner T5 NWC
Axle/Gears: Borg-Warner 7.75 with 3.27 ratio
Re: Keeps blowing fuse, alt bad?
That fuse by the battery, is it a 20 Amp fuse??
That fuse is the ECM power fuse, and it's supposed to be 20 Amps!!
The wire colours are Black and Orange/Black Stripe!!
I purchased a 1987 Z-28 that had the ECM fuse blown, and a fried fuel pump, once the fuel pump, and the ECM power fuse was replaced, it was good to go!!
No problems since!!
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