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Author Topic:   Fouled plugs
posted August 04, 2003 06:53 AM
This last weekend my car still was running bad.
One of the guy's running next to me just couldn't take it so he gave me a hand.

You said it sounded like I had a couple of dead cylinders. So he started pulling plug wires, with the car running, one by one.
And holding them close enough that the spark would still jump from the distributer cap to the wire.

He said (I believe) that the dead cylinder would run hotter.

My question how could he tell, was he looking for a different color spark, a different strenght to the spark, sound????

posted August 04, 2003 07:12 AM
Only thing I can think of was that if you start pulling plug wires, then when you pull the wire from the dead cylinder the rpm will not change and the dead cylinder is identified. If you pull the wire from a live cylinder the rpm will drop a noticable amount. Also I would think that a dead cylinder would run cooler due to the lack of combustion( less heat), but I may be way off on that one.

posted August 04, 2003 12:26 PM
you can use a infared temp gun on each header tube to identify dead cylinders. i dead one will be cooler....also works to see if you have a lean will be hotter


posted August 05, 2003 04:48 PM
If you are poor like me and need to know which cylinder is down, just grab a pair of pliers and an ice cube and go to each header coming out of the heads and see which one doesn't melt the cube as fast.

posted August 06, 2003 03:46 PM
Flanndad like bga said if you pull a wire and there is no change in sound or rpm that the bad one(s).

posted August 07, 2003 09:48 PM
The dead cyl. will be cooler, easy to see by sprinkling some water on each header tube one at a time. Dead cyl. will not vaporize like a good burning cyl.. Checking with a heat gun is the best way to do it though. Also it will be cooler since either there is no compression, spark, fuel(none or too much), or all three needed to create heat in a cylinder.

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