#1  
Old 11-09-2021, 07:39 PM
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67GP428 67GP428 is offline
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Default 12 volt wire that goes to the Alternator

The other day I accidentally hit my screwdriver to the 12 volt terminal that lands on the backside of the alternator. Sparks and burn smell happened!!! Question, down the line could of I done some damage? The other day driving home from a car show. My car would stop running as fast as a blink of a eye, then run like normal. Happened several times. I noticed the temp gauge went off the back on. Made it home and parked it for now. Any suggestions? 1965 B-Body with a PerTronix Electronic Ignition.

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Old 11-09-2021, 08:15 PM
punkin punkin is offline
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I'm not sure I fully understand. I don't know what this pertronix device is but,

IF the terminal you made contact with has 12 VDC coming from battery, or the ignition run circuit, I would be more concerned with the wire or insulation on that wire or, something closer to the DC source that feeds said terminal. The current would have flowed from the DC source on the said terminal to ground where you made contact. Meaning you could have pulled more current through the wire than it was rated for.

Now, IF the 12VDC on the terminal you touched is sourced from within the Pertronix device and you shorted it to ground, then current flowed again from the source (the pertronix device) to ground in which case high current would have flowed through the device. This could be a problem for the pertronix.

Since you say you saw other gauges now effected and it's intermittent...I think I would be looking for a cooked wire somewhere that is now either barely hanging on to it's connection point or the insulation could be burned off and occasionally making contact with something grounded.

Other's may have additional suggestions but I would be looking at the wiring...after a thorough inspection, maybe start the car up and wiggling/jiggling things. If you have a schematic follow that wire in the diagram and look it over. Be prepared to shut it down quickly if your issue stops being intermittent and more continuous. If that wire is not fused and finds ground continuously, it will cook until something opens the circuit. Is this a factory wiring setup?

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Old 11-10-2021, 11:02 AM
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the Pertonix. Is a pointless ignition. Yes it is a factory wiring harness. Thank you for your input.

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1965 Pontiac 2+2 421 HO auto
1967 Pontiac Grand Prix 428 4 speed- sold
1968 Firebird 400 auto - sold
1967 Bonneville Brougham 2 dr. hardtop. 1969 AMC Rebel SST wagon-sold
  #4  
Old 11-10-2021, 05:29 PM
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george kujanski george kujanski is offline
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Could very well be the fusible link was stressed. it'is a section of smaller gauge wire wrapped up typically in the harness running along the driver side valve cover. It acts as a fuse in case the wire to the alt is shorted to ground .It now seems to be intermittent.

George

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Old 11-10-2021, 06:43 PM
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Should be an insulator on the pole. Do you know if this is an alternator with internal regulator? Have you checked the voltage output from the alternator to insure your not over / Under charging?

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Old 11-10-2021, 07:48 PM
stellar stellar is offline
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X2 on the fuse link

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Old 11-11-2021, 09:28 AM
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Thank you all for your suggestions. When I get back in town ,I'll start digging into it more. I will keep you posted on what I find.

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1965 Pontiac 2+2 421 HO auto
1967 Pontiac Grand Prix 428 4 speed- sold
1968 Firebird 400 auto - sold
1967 Bonneville Brougham 2 dr. hardtop. 1969 AMC Rebel SST wagon-sold
  #8  
Old 11-15-2021, 10:56 AM
TxSportCoupe TxSportCoupe is offline
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Had same issue. When I peeled back the cover on the engine harness, I understood why. It was all crispy. Made a call to M&H Electrical Fabricators, installed a new engine harness, which was easy and, everything seems to work better. Lights were brighter. A/C blew harder. No more intermittent stall. I never tested the harness but Iím guess there was some resistance in that cooked harness. Youíll find it. Also distributor module may have been damaged when you arced. Though Iíve arced many times and that hasnít happened. Yet.


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Old 11-15-2021, 08:32 PM
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Good Idea. I'm going to call M&H tomorrow and order a new engine harness also.

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1965 Pontiac 2+2 421 HO auto
1967 Pontiac Grand Prix 428 4 speed- sold
1968 Firebird 400 auto - sold
1967 Bonneville Brougham 2 dr. hardtop. 1969 AMC Rebel SST wagon-sold
  #10  
Old 11-17-2021, 01:23 AM
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I made a call to M&H Auto wire. Asked about getting a engine compartment wiring harness. They are a minimum of 6 months out and have to send in my wiring harness fuse block connector. No hurry to go that route. Still haven't had a chance to dig into things.

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1965 Pontiac 2+2 421 HO auto
1967 Pontiac Grand Prix 428 4 speed- sold
1968 Firebird 400 auto - sold
1967 Bonneville Brougham 2 dr. hardtop. 1969 AMC Rebel SST wagon-sold
  #11  
Old 11-24-2021, 08:16 PM
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VCho455 VCho455 is offline
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It is possible you have damaged the rectifier (or the regulator) inside of the alternator and now the alternator is now sending out a bunch of AC voltage that is causing problems with the electronics in the Pertronix unit. Test the alternator for AC output.
Have you noticed extra static on your radio since?

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