Missfire R32 Gtr

[den001]

my 32 gtr likes missfiring only in 3rd gear onwards about 5000rpm in 3rd and most of 4 and 5th, under load.

i have changed my cas, igniter, and coilpacks, and fitted new plugs 2day....

still does it, no1 can figure out what it is....

any help???

mods are 12psi and full exhaust..

cheers

[Ronin 09]

is the coil loom in good nick?

earthed ok?

[den001]

i changed the loom also the earthing sraps are on the back of the coilpack wiring and also the igniter aswell

[DAN00H]

check your AFM wiring (not just at the connector)

[den001]

ok, will do, but if this was the case wouldnt it show up on the scanner as a fault???

they were running fine on the scanner when the car was on the dyno

[Amec]

injector(s) could also be the culprit. could pay to get them cleaned and flow tested.

I assume engine compression checks out ok?

[den001]

well, this is the thing, i done a test 2day.....

all dead even at 150 and i mean dead even except for cyl 2

witch had 50psi

i done a wet test then a leakdown test and it seems as its got a bent valve, must be by slightly so little, as the car still runs 11 sec quaters, wet test came back positive thats its not a piston or ring land, so i was happy... also, ive been told that its very very uncommon for cyl 2 to let go

was on teh dyno lastnite, and dyno operator stated that its running very rich.... plugs are a grey colour, indicated its burning fine, its very weird....

we also tried another ecu and same thing... still has that miss....

it mav be possible that its related to the leaking top end in cyl 2 but i have a reco head getting done now and will be slapped on by the end of the week

[scissored sil]

I have a similar issue in my 32GTR:

breaks down severly, only on full throttle, and only after about 4 to 4.5k rpm.

its got a Bee-R chipped ecu, looking to run about 1 bar.

I've tried changing plugs, tried a completely stock ecu, running back through standard boost solenoid.

compression tests at 160 across the board, with 150 on number 6.

But your problem is sounding very similar to mine, except i haven't checked my igniter yet.