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Knock Warning And Misfire

nakuma

By nakuma,
in Engines & Forced Induction

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nakuma Enthusiast

nakuma

Posted
Posted

Hey guys,

I've used the search function a lot but haven't come up with any definative answers yet.

My problem is; most times, during full load I'm getting a short burst of misfire after 5k rpm. During this time, the powerfc reads anywhere from 40 to 100 on the knock sensor. So I'm guessing the two issues are related.

I've had my coilpacks checked by re customs and they seem to think the coils are fine it's the rubber intake sucking closed. I also talked to rob at sabbadin and he assured me that 12psi is not enough pressure to suck the intake shut, even for a fairly degraded one.

I bought the parts to strengthen the intake but wasn't game enough to remove all the piping to get to the intake and I don't want to buy a solid one because I plan on upgrading the turbo after this issue is resolved.

Anyways, I took it to trent at status a few times before he went away and he kept taking timing out of the tune and it was fine for a while, but ever since this misfire issue has come up, it seems to be knocking (according to the commander) and misfiring a lot of the time under full load.

Any ideas?

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ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
Posted
Hey guys,

I've used the search function a lot but haven't come up with any definative answers yet.

My problem is; most times, during full load I'm getting a short burst of misfire after 5k rpm. During this time, the powerfc reads anywhere from 40 to 100 on the knock sensor. So I'm guessing the two issues are related.

I've had my coilpacks checked by re customs and they seem to think the coils are fine it's the rubber intake sucking closed. I also talked to rob at sabbadin and he assured me that 12psi is not enough pressure to suck the intake shut, even for a fairly degraded one.

I bought the parts to strengthen the intake but wasn't game enough to remove all the piping to get to the intake and I don't want to buy a solid one because I plan on upgrading the turbo after this issue is resolved.

Anyways, I took it to trent at status a few times before he went away and he kept taking timing out of the tune and it was fine for a while, but ever since this misfire issue has come up, it seems to be knocking (according to the commander) and misfiring a lot of the time under full load.

Any ideas?

i had a similar problem not long ago, it would start sputtering and missfiring after 4500 ish, i fixed it with new coils, new afm and did the induction pipe diy by putting a solid pipe in there, im not sure which one was the actual one at fault as i did them all at the same time, but perhaps you should check the same things i did.

and fyi, id drop ur psi down to 10, 12 is to much r&r imo

nakuma Enthusiast

nakuma

Posted
  • Author
Posted (edited)

thanks matt.

i was going to buy a set of yellowjackers, but after hearing from RE that the coils were fine and it could be the intake, then hearing from Rob that is shouldn't be the intake i'm a little torn.

i've got the parts for the DIY, but i'm not comfortable enough just yet to remove any of the intake pipes except for the cooler.

does the powerfc have a r&r safety feature?

also, i'd drop the boost, but i've only got the boost T that trent put in and i'm not sure how much i'd have to adjust it, let alone have to adjust it back after fixing the issue

Edited by nakuma
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
Posted
thanks matt.

i was going to buy a set of yellowjackers, but after hearing from RE that the coils were fine and it could be the intake, then hearing from Rob that is shouldn't be the intake i'm a little torn.

i've got the parts for the DIY, but i'm not comfortable enough just yet to remove any of the intake pipes except for the cooler.

does the powerfc have a r&r safety feature?

also, i'd drop the boost, but i've only got the boost T that trent put in and i'm not sure how much i'd have to adjust it, let alone have to adjust it back after fixing the issue

if u live close by i can give u a hand with ur intake pipe, its very easy, hardest bit is taking off the piping, do u have a fmic or smic? (side mount of front mount)

for re to just say, it aint the coils its the intake, is a bit quick of them, did they dyno it or anything? or just pull the answer from no where?

nakuma Enthusiast

nakuma

Posted
  • Author
Posted

that would be great clutch, i'd reimburse you for your time

not sure what RE did, no dyno. they had a look while they changed the water pump i think. not sure how thorough they were

the main concern at the moment is the knock levels the powerfc is showing. i real don't want to do any damage. did yours do the same thing in that regard?

the knock level spiked to 83 tonight when i loaded it up going from 80 in 4th (without misfiring), but every other time the high knock reading is coupled with the popping from the exhaust.

anyone else have any opinions?

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

do the intake mod, its super easy.

fit new plugs and gap them down if need be (until they stop missing under load)

if it still knocks use the temporary adjustment on the pfc to pull out a couple of degrees of timing and see if it still knocks

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