My project Pantera came with the large blue MSD 8253 coil. This is first time I have used such and I seem to be getting some plug wire crossfire from it. I am in the process of rearranging the plug wires to minimize any contact between them, especially the long runs of the wires. I also rerouted the coil wire to avoid contact with any wires and metal.
Does anyone have any experience with crossfire issues and can shed more light on this problem? Thanks!
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...how are you aware you have cross-firing??
1. Are you running a 'Cap and Rotor'??
2. Have you performed the 'Blackout' test, I have described recently??
3. Plug Wires # 5 and 6 are known to 'Share' Sparking/cross-firing easily, because they Fire One Right After The Other!
4. in your picture...if 'that' is how you have both the Control Module and the Coil mounted together on the same plate, I would say, the High Tension 'Stud' is Very close to the Grounded Case of the Module! Not much of a THIN Plastic Insulation to protect from a 'Potential' 50-60 KVOLTS that can easily 'Jump' close to a One Inch 'Air Gap'!!
Do the 'Blacked-Out Garage' Test, ALL will be Revealed!
Marlin
P.S. to answer your question, in My experience, there can be arcing at the Metal Clamps used to separate, and Support the Plug Wires, Because They Are GROUNDED. Never loose respect for what Electrical Engineers refer to as 'The Potential'! Electricity is ALWAYS seeking Ground! Always doing What 'IT' WANTS to Do!
Last...if the Cross-firing Only happens at Higher RPM's, it is because the Alternator is Boosting the System Voltage and Higher Voltage results in a Hotter Spark, capable of 'Jumping' a Larger Gap!
** Update ** The problem is resolved. Carefully rerouting, separating, and inulating the plug and coil wires fixed it. It looks wonky at the moment but misfiring is gone.
Answers to Marlin's questions:
The symptom was popping out of a couple of the passenger side throttle bodies when accelerating. There was also sporadic dips in the idle. Both of these symptoms are gone.
1. Holley Dual Sync distributor. It is needed by the Terminator X ECU.
2. Blackout Test - Yes. I coincidentally tried it early this morning when it was still dark. I could not see any arcing.
3. #5 and #6 seem okay. I think most of the problem was on the passenger side. There was popping out of a couple of the throttle bodies.
4.It is probably okay as is. The prior owner ran it that way for years.
I completely agree that electricity always want to find a ground. I think the big coil amplifies this notion.
Thanks Marlin!
