Alternator won't charge
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1st Gear
Joined: Dec 2024
Posts: 1
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Alternator won't charge
So here's what happened and where I'm at now.
I purchased a 87 and a 89 Corvette a few months ago as project vehicles.
On the 89 I installed a new alternator, PS pump and new belt. Fixed the drivability issues.
I drove it about 6 times for around a total of 120 miles since then.
So about a week ago I was just crusing around town and saw that my voltage was no longer reading the standard 14.3 or 13.4 volts and was dropping steadily. Headed home immediately.
The next day I removed the alternator and found the problem. The entire internals on the back side of the alternator had detonated and was in pieces. Took the new alternator I had for my 87 and installed it and I've got a no charge issue.
Checking the pigtail wire I've got 12v at both the red and blue wires while running. Also have 12v at the main lead wiring coming off the alternator but it will not charge.
So I began checking fuses. I found that the car hasn't had a gauges fuse in it since I've owned it. Upon putting in a fuse while it was running I found out why. Blew the fuse immediately. So I shorted the terminals together with a pair of pliers and it attempted to shut off the engine. So that's definitely an issue I'll have to track down.
However, it was charging before the alternator detonated itself. Anyone have any ideas as to what would cause this?
I purchased a 87 and a 89 Corvette a few months ago as project vehicles.
On the 89 I installed a new alternator, PS pump and new belt. Fixed the drivability issues.
I drove it about 6 times for around a total of 120 miles since then.
So about a week ago I was just crusing around town and saw that my voltage was no longer reading the standard 14.3 or 13.4 volts and was dropping steadily. Headed home immediately.
The next day I removed the alternator and found the problem. The entire internals on the back side of the alternator had detonated and was in pieces. Took the new alternator I had for my 87 and installed it and I've got a no charge issue.
Checking the pigtail wire I've got 12v at both the red and blue wires while running. Also have 12v at the main lead wiring coming off the alternator but it will not charge.
So I began checking fuses. I found that the car hasn't had a gauges fuse in it since I've owned it. Upon putting in a fuse while it was running I found out why. Blew the fuse immediately. So I shorted the terminals together with a pair of pliers and it attempted to shut off the engine. So that's definitely an issue I'll have to track down.
However, it was charging before the alternator detonated itself. Anyone have any ideas as to what would cause this?
Safety Car
Joined: Mar 2017
Posts: 4,202
Likes: 1,323
From: LeClaire Iowa
I believe if a fuse blows right away you have a dead short to ground. They are not always easy to find. Maybe somebody who know the best system will jump in. It usually requires isolating subsystems until the fuse does not blow. Dan edit: don't short the fuse terminals any more as you can really damage things or start a fire.
