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Plug readings on 96 57L 4bbl thunderbolt

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bill_k

Regular Contributor
"All of the plugs I pulled loo

"All of the plugs I pulled looked great nice and clean but the number 3 plug was really black. any thoughts on this, I'm thinking but hoping not that it is a bad valve?? Engine runs great and starts right up no problems."
 
Either a bad wire or a bad plu

Either a bad wire or a bad plug or both.

If it was not wet or oily but just black soot than it is probably wire or plug or both
 
"yes just black soot not wet,

"yes just black soot not wet, I just put a new cap, rotor, wires, and plugs in a week ago. wonder if I got a bad wire."
 
"Make sure you have the firing

"Make sure you have the firing order correct.

Make sure the wire is on all the way on the spark plug, Can be tricky sometimes.

You can also measure the plug wire resistance. Typically the resistance is ~5000 ohms per foot
So the number 3 wire is ~ 30 inches or so, so you should have ~ 15000 ohms. If it is 20000 - 25000 or more than the wire is no good. Of course that is based on a 30-36 inch long wire. If you get no ohms reading then the wire is broken so move the wire around when checking it to see if the reading stays steady.

I would swap the 3 wire and 5 wire both at the cap and the plugs and see if the problem follows."
 
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