spark plugs

[mad max]

need help car misfires put new plugs in fine after 800miles car misfires again put new plugs in fine only done 400 approx same thing cleaned plugs looked ok still misfires under boost :?

 

[c20ona]

Check the HT leads mate. Do they pop off at all ? (try pushing them to see if they click back in place after driving). If so, could have blocked air outlets on the leads (i had this problem). + Could also check the dizzy, rotor etc too.

Kenny

 

[mad max]

spark plugs

put new leads +dizzy+rotor not to sure what you mean about air outlets on leads :?:

 

[AJ4]

If you look at the top of the lead, its the round rubber disc bit that plugs onto the rocker cover and seals the plug chamber. The disc part should have a small hole in the top to allow air in and out as the engine heats ups/ cools down.

 

[DOT2DOT]

what difference will that make? Will a hole not let water in?

 

[AJ4]

no, the hole is tiny,just enough to let air in and out. If it was a tight seal, when the engine heats up the expanded air in the plug chamber would pop the leads off In order for the vent holes to be submerged, the water would have to be about an inch deep, the vent holes are too small for water to run in anyway, they're about half a mm across. The only way it could get in is if they were submerged and the engine cooled, sucking it in.

 

[DOT2DOT]

Interesting indeed, i must check mine!