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Guest Anonymous

Ignition short - electrical gurus needed

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Guest Anonymous

So, I posted a little earlier about the starter problem I was having. A little wiggling of the wires and the intermittent starting trouble hasn't shown up again.

Now the problem is a lot worse. I was troubleshooting and had the ignition on for about 30 seconds and the ignition wire going into the coil started smoking. I turned off the ignition and the smoking stopped. I checked everything I could think of before turning the ignition back on and then it started smoking again right away. It sounds to me like I have a short somewhere.

The question is, where is the short? Basic electical theory tells me that the wire would only heat up between the positive terminal and the short, not on the wire beyond the short. Could I be seeing something weird related to the a bad engine ground? Could it be trying to ground through the coil and therefore the ignition wire?

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Guest Anonymous

Double check your engine ground (if you haven't moved your battery there are two) and the ground between your alternator and the head. Remove the bolt on both ends, scrape the connection clean with some sandpaper (get it nice and shinny) and reassemble.

It's possible (not likely) your coil has gone south, most often they seem to fail open not as a dead short.

Cheers!

John N

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Guest Anonymous

What should the resistance be across the coil?

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Guest Anonymous

My guess is that you have some other wire on the supply terminal (15) of the coil, and that extra wire is grounded somewhere. Ignition wiring varies slightly with model year, and I don't know yours, but the basic setup is below. Check your wiring, then report back.

Green: Ignition switch to Fuse 11 to Ballast Relay (30).

Green: Relay (30) to Ballast Resistor (one end).

Green/Red: Ballast (other end) to Coil (15).

Green/Red: Relay (87) to Coil (15)

Black: Coil (1) to Distributor

Black: Tachometer to Distributor or to Coil (1).

Brown: Relay (85) to body.

(Violet?): Ignition switch start terminal to Relay (86).

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Guest Anonymous

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Max has them for a couple bucks, or you can get spec. resistance and find at wherever. But, I would stick to Bosch stuff. Important to have - may be part of problem. since you dont have other ignition components, you can isolate problem. get that resistor- i dont care what anyone sez about running w/o one: both my cars have Bosch red and both run external Bosch ballast resistor cuz experts said it must be done. Both my cars run great with the set up. good luck. Call Matt now, or any other. Bosch red stuff is now almost NLA: so you need to get on it.

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Guest Anonymous

Well I'm pretty sure it's a short now. I've unhooked the positive input from the ignition coil and it's definitely grounded somewhere. That would explain the smoking. I cut the wire wrapping off along the firewall and I can see this length of wire has been replaced before. Oh joy. I guess I'll be busy ripping out wires over the next few days...

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