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Discussion Starter · #1 ·
I just finished dropping in a new 468 BBC into my '71 SS after 2 long years of waiting. When I hooked up the '+' (positive) lead to the starter(this cable has an accessory lead that goes to the fuse panel) I suddenly have 12V over the entire car. I have disconnected the lead to the starter and all the other aux wiring to where it is back to what it was when I parked it 2 years ago. Has anyone had a similiar experience or any suggestions where to look in the stock wiring system for a short? This has been a real bummer of a set-back so any help would be greatly appreciated.

Thank you all,
BC


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what do you mean "12V over the entire car" ?
I assume you mean sparks

Did you try touching the pos. cable to the starter post only, maybe the starter is the problem. If there is a short in the acc. power lead it should have blown the fusible link.

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Dean Call
A.C.E.S. # 00235
N.C.O.A. # 4350

macc.chevelles.net
 

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Discussion Starter · #3 ·
Dean,
I had the positive cable connected and when I went to connect the negative lead, I got some sparks. I quickly disconnected the negative lead and started in with the voltmeter. I have 12V between the negative battery terminal(all wires disconnected) and anywhere on the motor/car. I disconnected the cable to the starter, and the problem persists, so I don't think it's the starter. Now, all I have hooked up is the acc. power lead to the positive terminal and the problem is still there. Under the dash, I did notice a ground wire that was severly melted, but that was my fault for having it connected to the wrong lead...That has been disconnected. Does anyone have a readable wiring diagram that shows the route and connections of the acc power lead?

Thanks,
BC



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One way of looking to see what circuit is drawing current is to start removing fuses out of the dash one at a time and checking for the draw. Maybe you will be able to isolate the circuit in that manner. It could be something simple like maybe the brake lights stuck on or something of that nature. If there is a short before the fuse box, then this method won't work. If it doesn't, then disconnect the alternator and check it. I've seen alternators do this before.
 

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I just went through the same exact problem. Went to connect the negative terminal and sparks flew. Turned out to be corroded ground wires in My 71 SS454. I wound up replacing the battery cables (wire to starter), copper ground wires(3), and then the front lamp harness and engine wiring harness after I noticed that several wires were starting to burn through. I can't tell you how many people have said how important grounds are!!


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Discussion Starter · #6 ·
Thanks for all the great suggestions....however, I did disconnect the alternator connections and the problems still exists. I don't think it would be a ground problem since we're talking positive voltage where the ground shound be and the negative battery terminal is not even hooked up. I haven't tried the fuse pulling thing yet, but wouldn't this type of short blow the fuse?? I'm still looking, so keep the suggestions coming.
Thanks,
BC


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How much sparking are we talking about? Like directly connecting the pos. and neg. terminals with a wire?? Are your lights turned on? Go through and make sure that there's nothing at all turned on.
I think it would be normal to measure 12 volts between the pos. cable and the pos battery post. Try setting your meter to 10Amps and making the connection between the cable and the post with the meter. If your meter is not fused (read your manual) then connect a fuse in series with the meter. Use like a 7.5 amp fuse. That way the fuse blows and not the meter.
 

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Discussion Starter · #8 ·
Dave,
Thanks for the suggestions, When I said positive voltage, it is measured between the negative battery terminal, which is not hooked to any cables, and the entire ground field. The only connection made is the positive accessory lead. If I disconnect this lead, problems goes away. It all seems to point to a major short between the battery and the fuse box since none of the fuses were blown when I tried to hook up the negative lead. Yes, this is exactly like touching the positive and negative terminals with a wire.

Thanks for the input,
BC
 

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I would disconnect the + @ the fuse box, set your meter on ohm hook 1 lead to the wire and the other to the car to see if there is a reading. The wire might have a cut in it.
 

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BC,
I think you may be confusing yourself slightly. If you disconnect the negative battery cable from the battery and connect your voltmeter from the negative battery terminal to the negative cable, or any other ground, you WILL read twelve volts if ANYTHING, and I mean anything is turned on. This could be the dome light, radio memory with a newer radio, clock, etc. Any device that is turned on or working will cause the twelve volts to be read. Make sure you understand this before you start troubleshooting or you will run yourself in circles. If you need a better explaination, e-mail me and I will try to draw a diagram and e-mail it to you.
If I were working on this problem, I would disconnect the fuse box connector on the firewall for starters, that would at least isolate a big part of the electrical system and help you start in the right direction.
Hope this helps.

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Bill Koustenis
Advanced Automotive Machine
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