Coil sparking
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Fleet Mechanic
Joined: Jul 2002
Posts: 1,297
Likes: 34
From: S/W Virginia
Coil sparking
With the coil wire unplugged, when cranking the engine the coil will spark to itself. This does not seem right to me. I tried another old coil I had and it does the same thing. What would cause this?
Hotshot
Joined: Feb 2004
Posts: 10,764
Likes: 2,590
From: The Shenandoah Valley
You seeing this with the coil to distributor lead removed maybe? A hot coil with the high tension lead removed is looking for a place to discharge pent up renergy. The smaller wires still hooked up to + and - terminals, and when the - is interrupted by points opening or the Dura Spark ... a hot spark is generated. Normally it would follow the lead to the rotor in the distributor cap to a plug lead terminal to a plug, to ground at the plug tip, but by removing the lead you removed that path, so it jumps to the coil case or the - terminal when the points close or Dura Spark starts the next dwell period...
Why are you cranking it with the lead removed?
Why are you cranking it with the lead removed?
Hotshot
Joined: Feb 2004
Posts: 10,764
Likes: 2,590
From: The Shenandoah Valley
I converted my '69 Dart over to the then new Chrysler Electronic ignition that was new in early '70s, I had a Accell Super-Coil on the firewall, friend jumped in my car and turned key to start when I was under the hood, I did not tell or ask him too. I saw the spark jump from the coil tower to negative post, POP, blew out my brand new electronic ignition control box. I had the coil lead hooked at the distributor cap end, but not yet at the coil end. I put the points set up back in, was a dual point factory distributor .... I bought a few control boxes then. They were only about $20 at Virginia Auto Parts .... a wrecking yard not far. Nothing special about them, same as was used on all of the Chrysler cars by then.
He did later swear he knew I was over on the side near the firewall, not near the fan. He meant well I guess. My screw up was not putting my keys in my pocket, lesson learned.
NOT SAYING that your Dura Spark is toast, but it is a possibility to be aware of.
He did later swear he knew I was over on the side near the firewall, not near the fan. He meant well I guess. My screw up was not putting my keys in my pocket, lesson learned.
NOT SAYING that your Dura Spark is toast, but it is a possibility to be aware of.
Logistics Pro
Joined: Oct 2006
Posts: 4,028
Likes: 890
From: East Central Ia
Coil sparking with no easy return to ground is hard on ignition components. To the people that pull plug wires to see if it makes a difference in rpm just be careful or just don't do it to powerful electronic ignitions. Duraspark is powerful enough to jump an inch. Don't be between the open coil and ground, or you will be the ground.
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billdevaul
1967 - 1972 F-100 & Larger F-Series Trucks
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Feb 26, 2013 11:09 AM
