Missfire Boost@4500-5500 RPM - The Answer! (for me at least!)

[ZigenGT]

I've had the same problem for a while. Just bought a set from another forum member who claims his is perfect. Hope this does the trick!

[nsta]

hey guys, how much does it cost to gap the coils?, as i'd like to try this out, since my car misses heavy anything over 7psi!!!, who does this sort of thing, and how much do i need them gapped, i got stock coils.

[Fixxxer]

hey guys, how much does it cost to gap the coils?, as i'd like to try this out, since my car misses heavy anything over 7psi!!!, who does this sort of thing, and how much do i need them gapped, i got stock coils.

<{POST_SNAPBACK}>

You gap the spark plugs, not the coils. If you are running more than stock boost you should be running a smaller gap than 1.1mm, most use 0.8mm gap. I use NGK Copper plugs.

Have a look back through the beginning 3-4 pages of this thread and you'll see how to tape up the coils with electrical tape, or use some other type of insulator on the coils (like araldyte glue around the coils). The coils may either have a very tiny crack in them, or have a discolouration due to arcing.

New plugs gapped correctly and further insulating the coils will go a long way to solving your missfiring issues.

Fixxxer

[d-d]

There were too many pages before this for me to read

But i found the quickest easiest solution for me was to just buy a set of Splitfires and wach them in!!

The car runs like a dream now, i just wish i had them put in 1/2 yr ago now!!!

[sl33py]

Just buy the splitfires. 500 from perfectrun.com.au any other fix is temporary. When I pulled them out of the box my first thought was "woah.. nothing's gonna arc through THAT" You have to pull them out to do the taping or whatever, so might as well pull them out once and be done with it.

[Zahos]

From the other thread here, I just noted last week that i covered them with araldite over 17 months ago, and not a single hickup yet. I wouldn't call that temporary.

But not everyone's coils are simply cracked. There could be some other issue...

It's worth the try, my $5 and 1hours effort has come a long way...

[Fixxxer]

Guide to fixing missfiring issues.

Step 1: Gap spark plugs to 0.8mm if you're running over standard boost. (Copper plugs seem to work fine and are cheap). If this does not work try Step 2.

Step 2: Insulate the coils with good quality electrical tape, or for a more permanent approach, araldite them. If this does not work, try Step 3.

Step 3: Buy some splitfires.

I don't think 2 cars are really the same. Mine had major missfiring issues and major discolouration due to arcing on ALL the coils. Mine was solved with just Step 1. Does not missfire at all on boost anymore. If/when it does start missfiring again I'll change the plugs and look into the araldite trick before spending over $500 on splitfires.

Fixxxer

[nsta]

mmm interesting, mine were still stock 1.1gap, and we gapped them right down to about .6mm is this bad, it seems to have solved the issue as i havent had a hiccup yet, touch wood:)

[Fixxxer]

I would have tried 0.8mm first, but if its working for you, and the car seems fine at idle and through the rev range then its all good

Fixxxer

[mabru]

I would just like to add a little bit to this massive thread. My 25DET is getting really bad with this 4k rpm miss ............and I run Splitfires, so no solution is permanent.

Edit: Fixed it. Car ran great last night then like crap this morning. I ran some errands and it wouldn't start after about one hour of operation. I managed to start it and it wouldn't rev above 2000 rpm, I also noticed the AFR showed that the injectors weren't pulsing above 2000rpm but the AFM voltage was fine. I nursed it home and threw on a spare CAS I had laying around, problem solved No more misfires, pulls to redline, no more sputtering. Finally.

Edited February 9, 2006 by mabru

[brenr33]

i used plasti dip spray much neater & it dosent fall off ( plastidip.com )

[driftmeister]

I changed the plug to the original spec for GTT (Guess its platinum) heat range 6. As for NGK copper, what s the code part number & heat range are u guys running? Hope this time it's fix the misfiring (hiccup). Last resort would be Splitfires coils.

[Booya]

Ive had the SLIP, ENGINE AND TCS lights come on everytime i start for about a month now, it ocmes on as soon as the engine warms up.

And just since yesterday its driving like a piece of crap. If you throttle it, it backfires constantly like some of the pistons aint goin.

I tried looking for the coil packs on the R34 but i couldnt get to it. ANy help on this would be great.

[driftmeister]

Guys...believe i or not.....hahahaha I managed to fix d problem. I can say it's my mistake for overlooking the power supply from the battery when i install amp & woofer for my listening pleasure. although it was bought brand new 2 month ago but the capacity or quality (locally made) wasn't up to task for the all the R&B bass & swingin house music!!.

My part supplier mentioned to me that quite a few GTT owner has the same problem as me, some even change battery (other makes) more than twice. It seem the original battery is specially made for our car & last longer.

So I went for a long drive (without my player switch on) and suddenly the misfiring begin to disapear as i drove longer, downshifting & open throttle to clean up all the carbon, bit by bit until it can handle full throttle without any hesitation. Engine now purrs like a kitten with very neutral exhaust smell (used to smell rich/lean..).

Hope my experienced would solved other owners in future. Many thanks guys for all the feedback...now mmmm Boost controller!! hehehehe

[driftmeister]

sorry ....car run with player switch OFF. Meaning amp is not ON at all throughout the journey.

[driftmeister]

Hi Booya,

Mine had the same TCS off & SLIP light on on some occasion. Best is to switch engine off, then start the car again. If it is still on then try giving it a rest for 5- 10 mins. Usually mine goes off after that. If you are in a hurry then take it for a short drive then stop and restart again. Everything will be back to normal. Not sure the battery solution would rectify this problem too.

[Luke 34GTT]

Hi guys, ever since i bought my 34 GTT, it has had (sometimes) a miss at 4500rpm, usually when i would first gas it after it warmed up etc, and i was starting to get really annoyed with it. After reading this thread i pulled out all my coils and had a good look at them, but they looked brand new. So then looked at the plugs, an saw that they were iridiums with a 1.1mm gap. After gapping them down to .7mm, and driving the car even after it first warms up, the miss is GONE! I can't beleive it was such a simple problem! Thanks for your help guys. Has anyone with a 34 fitted an safc? an did it make much of a difference, power wise etc?

[Booya]

Well tried the battery option last night removing all stereo components and thats definately not whats causing it.

Ill have to try to get to ther dam coil packs this weekend and pull out the sparkies and regap them.

Otherwise ill take it to a mechanice to have a look at. I checked the coil packs last night just by peaking under the rocker cover but i couldnt see any sparks.

It even started iddling funny when i first started the car COLD!

[MMM]

gotta take the whole coil pack out and check for cracks in the coil pack.. just by looking at them on top wont tell you nothing

[JimX]

gotta take the whole coil pack out and check for cracks in the coil pack.. just by looking at them on top wont tell you nothing

It can help, he was checking for sparks in the dark through bad coils, not looking for cracks in the top. If there's no sparks it doesn't mean the coils are good, but if there ARE sparks, then the coil is definitely faulty somehow.