Misfiring and shutting off after plug wire change
Thread Starter
1st Gear
Joined: Jun 2026
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Misfiring and shutting off after plug wire change
I changed plug wires today on my L82 79 and there's a misfire now, along with the car shutting off either in gear or park idling after about 30-45 seconds. Plug wires are seated well and nothing is crossed up on the distributor. Any help would be appreciated!
1967 Pedal Car Champion
Joined: Mar 2020
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From: US-PNW
Make sure both ends of the wires "click" onto the plug and distributor tower. Sometimes the connector can be pulled into the boot too far and doesn't make a good, secure connection.
After that, if the miss is still there, hook up a timing light and attache the pickup to each wire to check for consistent firing.
After that, if the miss is still there, hook up a timing light and attache the pickup to each wire to check for consistent firing.
Last edited by barkingrats; Jun 16, 2026 at 10:34 PM.
Melting Slicks
Joined: Apr 2021
Posts: 2,751
Likes: 2,193
From: Minnesota
Welcome to the forum!
New plug wires should make the car run better, not worse. Like what’s been mentioned I would make sure all the connections are fully seated. And while you’ve got a timing light on there I would check your actual timing. What is it set to?
New plug wires should make the car run better, not worse. Like what’s been mentioned I would make sure all the connections are fully seated. And while you’ve got a timing light on there I would check your actual timing. What is it set to?
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Did you route all wires as per factory? Did you pinch one while reinstalling the boomerang covers? Did you pinch one going through the motor mounts?
Did you use quality wires?
Did you use quality wires?
Melting Slicks
Joined: Oct 2003
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From: Chapel Hill NC
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Id double check routing and seating. Cracked a spark plug?
Instructor
Joined: Dec 2025
Posts: 102
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From: BC
I installed new plug wires recently. Then later I rechecked my work. Seemed good. Note that in the firing order, the distributor cap lugs 3 and 4 are positioned right beside each other. Your whole life 3 comes before 4. Except on a chevy v8. Here 4 comes before 3. An easy thing to overlook twice. I certainly did. I fixed my error and whadda ya know. The mis-fire was gone.
Last edited by C3Cruiser; Jun 17, 2026 at 05:50 PM.
Race Director
Joined: Mar 2017
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From: Virginia
Did you use loams, or something else to keep the wires separated? C3s love to cross-talk. If you used zip ties to neaten up the bundle of wires, you'll have an issue.
Welcome to the Forum, and please post some photos!
Welcome to the Forum, and please post some photos!
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From: cary Il
Le Mans Master
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From: melbourne florida
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I routed these with tie wraps first but if you do it right they will lay out just like these and I've never had a cross fire.ill try to find some wires and show how to do it.
The factory ran them close together. If you have a problem buy some better wires. Taylor makes good ones at a fair price.