missfire but only when cold.

W

woff

Member +
Slight problem, ive had this missfire ever since i changed the head gasket and cylinder head for a port and polished one on my ep91, checked all the obv things like plugs leads dizzy timing. wondering if it could be ringlands or something? ne1 had anything similar? chris.
 
dark_knight

dark_knight

Member +
@woff: i can put my money on the possibility that you have water in your spark plug silos. check that first.. on 2nd thoughts, interestingly enough, you mention that it only misfires when cold..? if you have water in the spark silos, when the engine gets hot, it's possible that the water evaporates and is spread on the top side of the silo which then clears the problem momentarily, until the water condenses when cool and settles back at the bottom causing problems. but again, over time, the engine should be able to dry itself out so how long have you had this problem..?
all the best mate..
 
W

woff

Member +
@cheshireglanza ive sprayed wd40 in the chamber and on the spark plug and started her up, obv she spluttered for a while and than ran ok. will see after work to see if all is good but seems ok at present. No oil coming out of breather pipe chap all is clean there :)

@spacecraft ive had the problem for 3months now i think, spark plugs where dry and seem fine, gap on plugs is also fine :)

Cheers chaps :) shall update later. here comes some rep (if it lets me)
 
W

woff

Member +
rite chaps it did no such thing :( so my plan of swapping the head back to the standard one goes on lol =/
 
Texx

Texx

Super Moderator
Could be caused by a weak spark. Would be worth checking the ignition coil ground connection, battery voltage during and just after starting the engine and also checking the condition of the contacts in the distributor cap and on the rotor arm. If you don't find anything obvious it would be worth trying a known good ignition coil.
 
dark_knight

dark_knight

Member +
this is one baffling one. do as Texx says and try a known working igniter. unlikely but it could be your suspect. misfiring is more often than not caused by an electrical (not mechanical) fault, so i highly doubt your head has something to do with it. highly unlikely, but again, still possible.. :|
 
W

woff

Member +
tried a ignitor today and still no good. built up the spare head ive got just going to check the shim clearences tomorrow and tht will be fitted on saturday :) all fun and games lol
 
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