Question about spark plug gap
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Registered User
Joined: Apr 2003
Posts: 44
From: Midland, TX
Question about spark plug gap
I am replacing my spark plugs and wires this weekend and i was wondering what i should gap my spark plugs at with the mods i have on my car. I have had this constant arc at the coil and i am hoping changing the plugs and wires will help. The plugs i have on right now are ngk's gapped at .05 and someone told me that i might have my plugs gapped wrong which is causing the arc going from the coil to the bracket. It is definatly not the coil because i have replaced it several times along with the ground strap that goes to the fender. Any suggestions?
Registered User
Joined: Feb 2003
Posts: 641
From: St. Charles, Il
I dont think plug gap is your problem unless there is another problem, or you gapped them to .100 or somthing. using a spark tester you can make the gap over an inch and watch it spark and it still wont arc at the coil. Granted the spark is only traveling through the atmosphere not several hundered of PSI compressed air. but still. Electricity always takes the path of least resistance. In this case there is less resistance from coil to coil mount then form coil secondary winding back to the battery negitive.
Lets follow the path.
Coil mounting bracket
If the mounting braket was damaged in some way it could be the problem, Very un-likely
The coil casing it-self could be cracked causing the arc, Fairly likely but you said you replaced the coil.
If the Coil wire was loose or burnt or it could have high resistance causing the problem. If the boots are damaged and not insolating properly it could cause the problem.
There could be high resistance in the opti due to a bent or burnt rotor causing the problem, fairly un-likely
The plug wires themselves could be burnt, If it runs and occasionaly arcs to the beacket this may be the problem, but i doubt they are all burnt.
the plug gap COULD be too high but .050 is the correct gap. however the electrode could be burnt or melted off (if you spray thats a possibility) fairly un-likely
last but not least you could have a bad engine ground on left side of the block near the starter.
Start by checking the ground and the coil wire for damage.
Lets follow the path.
Coil mounting bracket
If the mounting braket was damaged in some way it could be the problem, Very un-likely
The coil casing it-self could be cracked causing the arc, Fairly likely but you said you replaced the coil.
If the Coil wire was loose or burnt or it could have high resistance causing the problem. If the boots are damaged and not insolating properly it could cause the problem.
There could be high resistance in the opti due to a bent or burnt rotor causing the problem, fairly un-likely
The plug wires themselves could be burnt, If it runs and occasionaly arcs to the beacket this may be the problem, but i doubt they are all burnt.
the plug gap COULD be too high but .050 is the correct gap. however the electrode could be burnt or melted off (if you spray thats a possibility) fairly un-likely
last but not least you could have a bad engine ground on left side of the block near the starter.
Start by checking the ground and the coil wire for damage.
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