Jump to content
SAU Community

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


Recommended Posts

  • 2 weeks later...
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.

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

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!!!

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.

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...

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 :)

  • 3 weeks later...

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 :P No more misfires, pulls to redline, no more sputtering. Finally.

Edited by mabru
  • 3 weeks later...

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.

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.

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

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.

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! :D I can't beleive it was such a simple problem! Thanks for your help guys. :P Has anyone with a 34 fitted an safc? an did it make much of a difference, power wise etc?

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!

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Latest Posts

    • So, that is it! It is a pretty expensive process with the ATF costing 50-100 per 5 litres, and a mechanic will probably charge plenty because they don't want to do it. Still, considering how dirty my fluid was at 120,000klm I think it would be worth doing more like every 80,000 to keep the trans happy, they are very expensive to replace. The job is not that hard if you have the specialist tools so you can save a bit of money and do it yourself!
    • OK, onto filling. So I don't really have any pics, but will describe the process as best I can. The USDM workshop manual also covers it from TM-285 onwards. First, make sure the drain plug (17mm) is snug. Not too tight yet because it is coming off again. Note it does have a copper washer that you could replace or anneal (heat up with a blow torch) to seal nicely. Remove the fill plug, which has an inhex (I think it was 6mm but didn't check). Then, screw in the fill fitting, making sure it has a suitable o-ring (mine came without but I think it is meant to be supplied). It is important that you only screw it in hand tight. I didn't get a good pic of it, but the fill plug leads to a tube about 70mm long inside the transmission. This sets the factory level for fluid in the trans (above the join line for the pan!) and will take about 3l to fill. You then need to connect your fluid pump to the fitting via a hose, and pump in whatever amount of fluid you removed (maybe 3 litres, in my case 7 litres). If you put in more than 3l, it will spill out when you remove the fitting, so do quickly and with a drain pan underneath. Once you have pumped in the required amount of clean ATF, you start the engine and run it for 3 minutes to let the fluid circulate. Don't run it longer and if possible check the fluid temp is under 40oC (Ecutek shows Auto Trans Fluid temp now, or you could use an infrared temp gun on the bottom of the pan). The manual stresses the bit about fluid temperature because it expands when hot an might result in an underfil. So from here, the factory manual says to do the "spill and fill" again, and I did. That is, put an oil pan under the drain plug and undo it with a 17mm spanner, then watch your expensive fluid fall back out again, you should get about 3 litres.  Then, put the drain plug back in, pump 3 litres back in through the fill plug with the fitting and pump, disconnect the fill fitting and replace the fill plug, start the car and run for another 3 minutes (making sure the temp is still under 40oC). The manual then asks for a 3rd "spill and fill" just like above. I also did that and so had put 13l in by now.  This time they want you to keep the engine running and run the transmission through R and D (I hope the wheels are still off the ground!) for a while, and allow the trans temp to get to 40oC, then engine off. Finally, back under the car and undo the fill plug to let the overfill drain out; it will stop running when fluid is at the top of the levelling tube. According to the factory, that is job done! Post that, I reconnected the fill fitting and pumped in an extra 0.5l. AMS says 1.5l overfill is safe, but I started with less to see how it goes, I will add another 1.0 litres later if I'm still not happy with the hot shifts.
    • OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers) Replacement of the Valve body (if you removed it) is the "reverse of assembly". Thread the electrical socket back up through the trans case, hold the valve body up and put in the bolts you removed, with the correct lengths in the correct locations Torque for the bolts in 8Nm only so I hope you have that torque wrench handy (it feels really loose). Plug the output speed sensor back in and clip the wiring into the 2 clips, replace the spring clip on the TCM socket and plug it back into the car loom. For the pan, the workshop manual states the following order: Again, the torque is 8Nm only.
    • One other thing to mention from my car before we reassemble and refill. Per that earlier diagram,   There should be 2x B length (40mm) and 6x C length (54mm). So I had incorrectly removed one extra bolt, which I assume was 40mm, but even so I have 4x B and 5x C.  Either, the factory made an assembly error (very unlikely), or someone had been in there before me. I vote for the latter because the TCM part number doesn't match my build date, I suspect the TCM was changed under warranty. This indeed led to much unbolting, rebolting, checking, measuring and swearing under the car.... In the end I left out 1x B bolt and put in a 54mm M6 bolt I already had to make sure it was all correct
    • A couple of notes about the TCM. Firstly, it is integrated into the valve body. If you need to replace the TCM for any reason you are following the procedure above The seppos say these fail all the time. I haven't seen or heard of one on here or locally, but that doesn't mean it can't happen. Finally, Ecutek are now offering tuning for the 7 speed TCM. It is basically like ECU tuning in that you have to buy a license for the computer, and then known parameters can be reset. This is all very new and at the moment they are focussing on more aggressive gear holding in sports or sports+ mode, 2 gear launches for drag racing etc. It doesn't seem to affect shift speed like you can on some transmissions. Importantly for me, by having controllable shift points you can now raise the shift point as well as the ECU rev limit, together allowing it to rev a little higher when that is useful. In manual mode, my car shifts up automatically regardless of what I do which is good (because I don't have to worry about it) but bad (because I can't choose to rev a little higher when convenient).  TCMs can only be tuned from late 2016 onwards, and mine is apparently not one of those although the car build date was August 2016 (presumably a batch of ADM cars were done together, so this will probably be the situation for most ADM cars). No idea about JDM cars, and I'm looking into importing a later model valve body I can swap in. This is the top of my TCM A couple of numbers but no part number. Amayama can't find my specific car but it does say the following for Asia-RHD (interestingly, all out of stock....): So it looks like programable TCM are probably post September 2018 for "Asia RHD". When I read my part number out from Ecutek it was 31705-75X6D which did not match Amayama for my build date (Aug-2016)
×
×
  • Create New...