Yes, Another Missfire Thread

[MUZT3K]

ok guys, so my car is missfiring and i dont know why...ive upgraded my coil packs to split fires and my spark plugs to iriways which were like $36 a pop and were recommended on the forums and are only like 1k km old ..so whats next? im thinking of just cleaning the coil packs and giving that a go and also i dont have a cover over the coil packs and i heard that lets moisture in? so i might search for one because i have my car booked in for a tune next week any help would be great. thanks

[Count Grantleyish]

Coilpack loom?

You got a/m ecu?

[MUZT3K]

possible could be the coil pack loom..got stock ecu in there atm, putting a power fc next week

[Count Grantleyish]

Have you looked at AFM yet?

If this isn't it, time to call in real internet mechanic or ring your tuner, they should have some ideas.

[MUZT3K]

how can i see if my afm is faulty? well tomorow im going to pull out the coils and silcon spray them give em a nice clean i guess and maybe tighten the spark plugs abit

[Munkyb0y]

how much boost are you running, and what size gap on the plugs?

i would expect new coilpacks to handle 1.1mm plug at 12psi, but you might want to try running 0.8mm gap just to see if that solves your prob.

[MUZT3K]

running 12psi but it spikes 14psi, i got the ngk iriway spark plugs they come already gaped at .8mm.....im guessing maybe its because i bought the split fires second hand...but ive had them for like 6 months and no problem..im hoping its not the coils, and not the spark plugs lol because ive spent heaps on both of them. its not a really bad miss fire, just a few pops

[SargeRX8]

I doubt it has anything to do with the coilpack cover as there are people who sell custom vented ones to let out heat.

Have you had the engine bay washed or detailed? Does it pop constantly while accelerating?

[MUZT3K]

no i havnt had it washed or detailed, only when i have it on high boost it will pop when hitting 5k rpm, on low boost might pop a tiny bit. i heard wrappin ur coil packs in silcone works, wot kind of silcone do i use?

[SargeRX8]

Well that depends on the purpose of the silicone. Are you trying to retard water and keep moisture out? Are you trying to make a seal? If you're trying to keep water out, get a silicone which is safe for plastics(some of them have harmful fumes which can deteriorate plastics).

Did this start all of a sudden? Did you change anything? Is your engine running rich or lean? If its rich its unburnt fuel, if its lean, it could cause popping and it could mean your fuel pump is failing and falling behind when hitting high boost.

[TiTAN]

no i havnt had it washed or detailed, only when i have it on high boost it will pop when hitting 5k rpm, on low boost might pop a tiny bit. i heard wrappin ur coil packs in silcone works, wot kind of silcone do i use?

sounds like the stock ecu trying to protect your engine from too much boost, it will probably go away with the powerfc fitted.

[MUZT3K]

ok so i was bored at 1am and decided to pull apart my engine bay, i took out the coil packs and cleaned them with silcone spray coz they were WAAAY too dirty all over....pulled out the spark plugs, and i noticed 1 spark plug had alittle hairline fracture on the side of it, but because i didnt have a spare spark plug i just put it all back together n thought id give it a run...and now its not miss firing, could cleaning of the coil packs make it stop miss firing? and should i replace that 1 spark plug?

[boostn0199]

If it missies again its because its hitting 14psi with 1.1gap and just use the cheap copper ones if gona be running more than 12 psi get yourself a set of bcrpre7s like $3 each and they come gaped at 0.8 and that will not missfire under high boost. But yeah could of been just maybe the sparkplug was to loose or the coil pack wasnt on the spark plug well if its gone now.

[Count Grantleyish]

sounds like the stock ecu trying to protect your engine from too much boost, it will probably go away with the powerfc fitted.

This is most likely your problem.

If I remember correctly, stock ECU will have hissy fit when you run more than 10psi boost.

Get PFC tuned, it should solve the problem.

[MUZT3K]

If it missies again its because its hitting 14psi with 1.1gap and just use the cheap copper ones if gona be running more than 12 psi get yourself a set of bcrpre7s like $3 each and they come gaped at 0.8 and that will not missfire under high boost. But yeah could of been just maybe the sparkplug was to loose or the coil pack wasnt on the spark plug well if its gone now.

they arnt cheap spark plugs bro, they r ngk iriway7's $36 ea gaped at 0.8mm, i think it was because they were abit loose or coz the coil packs were dirty coz now its working fine :S.

[boostn0199]

they arnt cheap spark plugs bro, they r ngk iriway7's $36 ea gaped at 0.8mm, i think it was because they were abit loose or coz the coil packs were dirty coz now its working fine :S.

Nah im saying you should use the copper ones there the best at the end of the day. The iriway and all that is just waste of money for no gains.

[SlowSkyline]

agree with above, i had alot of problems with the ngk iridiums, swaped with coppers with .7 gap and no missfire anymore!

[MUZT3K]

Nah im saying you should use the copper ones there the best at the end of the day. The iriway and all that is just waste of money for no gains.

oh ok, well thanks for that..if it starts miss firing again i might go those then