So here is a new one for me, I hope one of you guru's of all things Fiat can help. So here we go, the little gray 79 has been running just fine, now all the sudden it is running on 3 cyliders. I have issolated the the non running cylinder to the rear most. This was done by pulling the plug wires one at a time. So now for the strange part, pulling the wire from the plug or dizzy cap has the same result. No fire on that cylinder. But if I hold the wire close to the plug or cap hole, there is a nice spark from the wire to the plug and it runs fine. Firing on all four. To recap, Spark Plug connected to the wire and dizzy, no fire (spark) plug wire far away from plug or cap, no fire, wire just apart (1/4") or so all is well. Ok all you guru's what your thought?
Mike
3 cylinder spider - help
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So Cal Mark
Re: 3 cylinder spider - help
when you force the spark to jump a big gap, the build up is greater and the spark is more intense. This is a good trick to get a partially fouled spark plug to fire. Remove the spark plug and clean it, then figure out what fouled it
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majicwrench
Re: 3 cylinder spider - help
Back "in the day" we would pull the wire away from the plug and run it that way a few minutes to clean a fouled plug, it worked well. The coil will only produce as much current and is required to jump all the gaps in the system, if everything is together well, maybe 10k volts. With the fouled plug, less than that. WHen you pull the wire away from the plug, the coil produces a LOT more voltage, perhaps up to 30k, and that big jolt hitting the plug makes it fire. This same reasoning applies to resister plug wires, they actually make for a better fire at the plug. First thing I would do is yank the plug and see if it looks fouled. May want to check the wire resistance too, or just try swapping a wire from a diff cylinder.
Keith
Keith
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co200balt
Re: 3 cylinder spider - help
I will give that a try. I did pull the plug and it did not look that bad. If it is fouled I am sure it is from the little bit of really bad / old gas still in the tank. I know , I know, quit messing around and do it right....