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Coil spark jumping


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#1 crewy

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Posted 30 August 2017 - 09:10 PM

I have spark jumping out from the top of the coil to the top terminals when reving the motor. I think it's making the car kinda lack power when trying to go threw the gears. Is it a bad coil. I tried even changing the coil wire and it still jumps could this be do to upgrading to an internal altenator. Need some thought would love to drive this thing the right way

#2 racerx

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Posted 30 August 2017 - 09:36 PM

Have u homed it out.

#3 racerx

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Posted 30 August 2017 - 09:37 PM

Meant ohmed it out? Sure way to tell.

#4 flatcat19

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Posted 30 August 2017 - 09:38 PM

Is this a stock coil? Have you done a dizzy upgrade?

Did you change wires with a new wire?

You can't hang if your nuts haven't dropped...it's physics


#5 wayno

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Posted 30 August 2017 - 09:50 PM

The only time I ever had arcing was when the distributor cap was very dirty(outside), same could likely happen if the top of the coil is dirty, older stuff with points was the worst for me, even the dirty wires would arc if they were touching anything metal.

I did have it happen with a matchbox also, but only once ever, but I will admit that it likely had not had a tune-up in 10 years, I am one of them guys that thinks if it ain't broke don't fix it, but that really doesn't apply to this situation.


 

 

 


#6 datzenmike

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Posted 31 August 2017 - 05:17 AM

I have spark jumping out from the top of the coil to the top terminals when reving the motor. I think it's making the car kinda lack power when trying to go threw the gears. Is it a bad coil. I tried even changing the coil wire and it still jumps could this be do to upgrading to an internal altenator. Need some thought would love to drive this thing the right way

 

Alternator will have nothing to do with the secondary voltage of the coil.

 

 

COIL

Inspect the tower for cracks or carbon tracking. 

Be sure the high tension wire is firmly seated down into the top of the coil

Be sure the nipple is tight fitting around the wire and the coil tower.

 

Replace as needed.

 

DISTRIBUTOR

Make sure the coil wire at the distributor cap is firmly plugged down into the cap.

Make sure all plug wires are firmly plugged into the cap and onto the plug ends. Don't assume. If there are any small gaps, this makes it harder for the spark to jump the plug gap and it WILL look for an easier path to ground like the coil negative terminal.

 

What you are trying to achieve hear is the plug gap being the easiest path for the spark to get to ground.


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#7 crewy

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Posted 01 September 2017 - 09:02 PM

Stock coil and dist. All the other wires look good from what I can tell. While idling it runs fine no arc until I Rev it up. Could it maybe a Crack cap.

#8 datzenmike

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Posted 01 September 2017 - 09:39 PM

If jumping at the coil, then the coil is the weak link. Inspect the top of the coil for cracks or carbon tracking. Doesn't really matter if stock or new it could be damaged. You'll actually have to take a good look.

 

Is the rubber nipple clean and undamaged and is it snug fitting?

Borrow another coil to distributor wire and see if this helps.

Rub the inner side of the nipple with dielectric grease and try.

 

My hesitation was intermittent spark jumping to the coil negative terminal. Easy to overlook tha tiny crack in the coil tower.

V73z3Mi.jpg


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#9 heywier427

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Posted 05 September 2017 - 09:06 AM

You can also try sanding the arcing area to remove the carbon tracking.  Works on the rubber bits as well.

 

Just replace it all with autozone stuffs.  If its not the problem, return it.  No questions asked.


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#10 datzenmike

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Posted 08 September 2017 - 06:48 AM

I've done this also with good results. It won't fix a crack though. Dielectric grease will help but not a real fix. In the '70s my Charger was a bitch to start in the winter. Next summer I pulled the intake off that had the coil on it, took it off and the underside, not visible, was carbon tracked.


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