another misfiring r33

[rb25]

hey guys

i know what your going to say 'search is your friend'. but i have read them and think i still need some help before blowing good money on aftermaket coil-packs i didnt need.

after installing a powerfc and upping the boost, the car has developed a misfire in two places. the first only happens about half of the time, when coming on boost at wot and low rpm, say 2900. and the second happens all of the time, at 5000rpm+ on full load. the tuner tried to get around it but thinks its the coil packs and couldn't really do much about it.

mods include: bkr7evx platinum plugs, hks fmic, cam gear at 3.5deg., powerfc, evc5 at 0.9bar, 3" full exhaust, shielded pod. te rest is stock turbo, inj, internals, manifolds etc...

i'm thinking one of the following:

collapsing pipe between tubo and afm

fatigued coil packs (highly likely)

air leak (unlikely - all new hoses and clamps etc.)

afm (dirty - i will ask the tuner if the voltage was ok, im sure he would have checked tho, if it was bad this would also eliminate the collapsing pipe)

plugs (fouled - i did the plugs myself at home, drove the car 20km to the dyno, not sure if they would foul up in this time)

any input appreciated.

-rb25

[White-R33]

Hey dude.

Had the samt problem with mine when i upped the boost... and i had the same thought, coil packs... but, I think i may had some good news for you.

It was only the spark plugs. Try putting in some normal NON platmum or iridium plugs, and make sure the gap is 0.6. Use NGK BCP6ES make sure its the NON RESISTOR type.

I'm pretty certain that this will stop your misfiring. Try this first before anything else, as it's the cheapet thing that could go wrong. - looking at your mods, its also the most likely.

Give it a go and lemme know how it goes .

M

[White-R33]

by the way, if the plug "model" name has "r" in it, it norally means resistor. ie : BCP6RES as opposed to BCP6ES ... big diff !

[predator]

um, you need the resistor type

[rb25]

yeah... i've previously used bcpr6es and they were good. will try a set at 0.6. nexus9, can i have my plugs back please?

[MJ]

hey ross im having the same problem........i have my car tuned now and i get a couple of slight misfires at 12psi, no where as bad as it was previously but its still annoying.

Im using the bcpr6es and it was suggested to me to try them at 0.6 too, i cant think of what else is doing it other then the coil packs as i dont use a afm now, changed fuel pump, changed plugs from bkr7evx and all hoses and connections are fine.

[Sydneykid]

I agree with the guys, plug gap is where I would start.

[rb25]

ok, sounds good. will try tomorrow.

[rb25]

ok, i threw a set of bcpr7es gapped to 0.71 and the misfire is still there. might be the coil packs after all.

-rb25

[rb25]

forgot to add, i checked the resistance across the coil packs when they were warm and they all read 1.5.