#1  
Old 11-04-2019, 10:04 PM
4dblnkldude's Avatar
4dblnkldude 4dblnkldude is offline
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Default Charging system? Diodes? Was running now it is not

I bought a big car (74 grandville) the other day. The battery cables were messed up so I needle nose vice gripped them on a newer battery. I got the car running, shut the car and figured tomorrow is another day. Well my dumbass closed the hood right on the vice grips, a couple sparks flew and I popped the hood back up right away. I removed the vice grips and shut the hood. Now when I got the right cables and hook a battery up the 10ga wire gets hot and i saw a tad of smoke from the alternator.
I checked the battery ground on the head, the two fuses are good by the alternator, and the cables are in good shape. Did I blow a diode? Any quick checks before I start removing fuses and harnesses etc. I sucks it gets dark at 530 now. Sucks working under drop lights.

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  #2  
Old 11-04-2019, 10:48 PM
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Bill Hanlon Bill Hanlon is offline
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Getting the smoke back in once it gets out is hard to do.

I'm assuming that this is an internally regulated alternator (no voltage regulator on the firewall).

Pull the big wire off of the alternator. Hook the battery back up. If everything works except it won't charge replace the alternator and consider yourself lucky.

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  #3  
Old 11-05-2019, 11:21 AM
"QUICK-SILVER" "QUICK-SILVER" is offline
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Hook a test light up between B+ cable end and B+ battery post. Light will be on if you have a short somewhere. It will help to pull courtesy/dome light fuse/s and clock fuse while doing this so the test light will go completely off when you find the short.

Then start un-bolting and un-plugging alternator wires.

Plastic in-line fuse holders are for accessories on this car.

The big charge and power supply wires would have/should have a short section of fusible link wire protecting them. Don't know if they're on the back of the alternator or down on the starter + post. If behind the alternator, it may have been one of them that smoked instead of the alternator itself.

The 10 awg that got hot run from B+ to back of alternator? Or back of alternator going into the harness down to the starter? Or something else?

B+ post grounded out, with engine running, should have blown a fusible link wire or come really close to it depending on how fast you got the hood back up.

I'd be kinda gentle while un-hooking and moving wires while watching the test light. Move too much at once and might break a short loose and not know where.

Clay

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  #4  
Old 11-05-2019, 12:12 PM
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george kujanski george kujanski is offline
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As Bill says, once the smoke escapes you can't get it back in.

Smoke from the alt is not a good thing and indicative of a problem in that area. Disconnect it from the rest of the system and check for otherwise normal operation.

George

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  #5  
Old 11-05-2019, 11:36 PM
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4dblnkldude 4dblnkldude is offline
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Thank you! I disconnected the wires under the red cap and hooked up the negative battery cable and all is well. I must've smoked that sucker.

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  #6  
Old 11-06-2019, 11:00 PM
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4dblnkldude 4dblnkldude is offline
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50 bucks down the drain.

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