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

[jutstar]

The answer for me was spark plugs, The bastard who i brought it off said he just changed them, but the mechanic said they were probably the original plugs that came with the car. put in some cheap copper plugs and gapped them at .8mm

No more missfire for Justin !!!

[Yidz]

Interesting you bring this thread back up. I had the same drama on the weekend after boosting mine to 13psi. I think my problem was the weather was cold making me hit the factory boost cutout. Now its back down to 11 to be safe and so far so good

[polishboi]

great fix guys fixed the problem nicely. was getting bad miss fire at around 12psi onwards! Removed spark plugs cleaned them Gapped them to 0.65mm and did the DIU and works a great!

[Black_CSR]

HI guys

I'm having the same problems.. i'm wondering if i should just my PowerFC tuned to fix it or get some Splitfires??

Ta

[Pashka]

I need help please, replaced coilpack to splitfire, brand new plugs, cleaned AFM

as soon as i boost the car to anything over 0.6 bar i get a missfire at 5000 rpm, its a very slight one but the higher the boost the more i feel it. car sort of backs off till 6000rpm and then goes off to red liner.

i have done alot of research on this but the most common issues on this problem i have already done.

anyone help please...

thank you

[WogsRus]

yeah same here, do you still run stock ecu. I had issues with the stock ecu runing rich and retard. Now i have a remaped ecu and it doesn't do it as much, but still seams to missfire a fair bit. No idea why? anyone who may have any ideas please let me know.

[Rolls]

Did you get it remapped to suit your car?

[zephyro90]

same problem with mine....

i used 3M rubber insulation tape and 3m vinyl tape. now i can rev upto 7000rpm no problem

thanks to these forum/topic.

[VLT025]

Hey guys I know this thread has been done to death, but after reading through every page of all these threads and having the same problem myself this is what I've believe to be true.

Most if not all of these problems seem to stem from the engine struggling to produce spark for 3 reasons;

1- First and foremost, too much fuel due to R&R effect when running higher than factory boost with exhaust/cooler upgrade

2- Too much fuel = plugs that foul quickly and cannot fire properly. Sure you can replace/re-gap etc but they will foul again

3- Extended periods of driving while struggling to produce spark at plug = spark looking for another way out = coils cracking and arcing out

If you think about it, this is why people are always finding that the quick fix isn't permanent. If you don't stop the engine from overfuelling, all of these other issues will surely re-occur. If you can attack this first, your plugs should last longer and be able to run larger gaps...and hopefully, your coils will last longer too...even if you have to go for the taping/araldite solution initially. If you think of it simply, the spark will go wherever take the least amount of effort....in short - try and make sure that place is your combustion chamber!

With regard to plugs, I have found the NGK R5671A-7's to be the best things around and they're like $4 each. They have the tip recessed further into the plug to help prevent the spark from being blown out and were recommended to me by an RB specialist who has uses these in every engine he comes across and has had great success every time. In fact, my car WOULD NOT boost past 10PSI no matter what I tried until I put these in. It still mis-fires at anything over 9-10PSI but I still have a stock ECU, like a lot of the cars with these problems

Edited January 24, 2008 by VLT025

[dnbutts]

awesome!!!

i have the EXACT same problem...will have a crack at this tommorow when the sun comes up!!!!

thankyou!!!

[made_guy]

i'm changing my plugs at the moment - they had heat range 5 platinum plugs in them gapped at 1.1 and i'm moving to

copper heat range 6 - gapped at 0.7.

I also siliconed the coils with selleys 401 (good for a bit over 200degrees)

i had added a front mount/pod/full exhaust and was getting serious missfire whenever i was flooring it from like 3000 up to 6000rpm so have wound boost back to about 8 in the meantime and kept my driving pretty mild.

should have the plugs done and coils in tonight so i'll give an update tomorrow on how it pans out.

[made_guy]

^^^ woop woop!

no more snap-crackle-pop!

definitely suggest changing/gapping plugs (i used BCPR6ES at 0.7) and why not silicone your coils while you're at it...?

[MotoMan]

I was having missfire issues at 4500rpm and up

Have

R34 SMIC

running 9.5 PSI single stage boost..

HKS superdragger Catback

Copper Plugs 1.1mm GAP

SAFCII installed but not tuned yet..

Figured it was rich+retard as it was dead on 4500rpm+

Today i removed the coils and taped them up..

BANG.. No more missfire.. pulls hard all the way to redline

Will invest in some Splitfires soon.. currently around $495

Would highly recommend taping up your coils if you are having this issue..

It takes around 1hr to remove/tape/put back together and is a sure fire way to see if coils are the issue

You shouldnt need to be gapping the plugs at around stock boost/minimal mods

Gapping the plugs isn't the solution.. Sure it fixes the missfire.. but the coils are still the issue

If anyone needs help, im happy to guide/help.. as this forum has been an invaluable source of information and help to me

Edited February 11, 2008 by MotoMan

[made_guy]

go the supersparks from kudos if you're going to get new coilpacks - splitfires are only an OEM replacement. i think the supersparks have thicker construction and are a better overall coil

[MotoMan]

go the supersparks from kudos if you're going to get new coilpacks - splitfires are only an OEM replacement. i think the supersparks have thicker construction and are a better overall coil

Problem is the supersparks.. just like the Justjap coilpacks are for Series one only..

The only replacement for a series 2 is Splitfires... they are cheaper than supersparks too.. at only $485 Delivered

[made_guy]

yeah i saw Kudos only selling them for series 1, but when superspark advertise (in magazines that is) they say they make them for both series 1 and 2...?

[Blue_J]

Had this exact problem in my 34 GTT

Changed out old plugs (1.1mm) with some .8mm copper plugs and now she runs sweeeeeeet!!

Had a close look at my coil packs but they looked in good nick, no cracks that I could see.

I would suggest to re-gap your plugs or just put some smaller gap copper plugs (~$20 all up!) before lashing out on some splitfires. Though wouldn't mind some splitfires myself. Iridiums/plats are a good idea on the gtt's simply because changing plugs is a bit of a pain in the butt.

[MotoMan]

Had this exact problem in my 34 GTT

Changed out old plugs (1.1mm) with some .8mm copper plugs and now she runs sweeeeeeet!!

Had a close look at my coil packs but they looked in good nick, no cracks that I could see.

I would suggest to re-gap your plugs or just put some smaller gap copper plugs (~$20 all up!) before lashing out on some splitfires. Though wouldn't mind some splitfires myself. Iridiums/plats are a good idea on the gtt's simply because changing plugs is a bit of a pain in the butt.

Thats a band aid solution...

I changed mine to .8 and it ran fine.. but you shouldnt have to run 0.8 gap around stock boost.. so i changed back to 1.1 and the missfire came back

Took my coils out.. They looked perfect.. no cracks etc.. decided to tape them up anyway..

and SHAZAM! no more missfire with 1.1mm gap plugs..

Highly recommend taping the coils (even if they look perfect) before considering changing to a smaller gap

[The BOP]

Hey mate your in luck I just bought a set of splitfire coil packs (full set) they suit an RB26DETT RB25DE RB20DET RB20DE

there brand new and in the box I'll get rid of them for $450. The reason I'm selling is I bought the wrong one's for my car anyway let me know if your keen cheer's you can catch me at [email protected] and I'll check here too

Dave '

just been to tuners and have now got missfire around 17 lb boost and around 5-6 000 rpm, didn,t have this before , tuner says a coil has decided to break down , do you have any other ideas or a set of good coils i can buy please.

Kind regards

dave

[SIMO]

Hey, I got same sorta problem, missifre at 4000rpm, missfires if i put the foot to the floor. Coughs n splutters like a mofo on deceleration. Sounds way too rich. Drives fine at half throttle though. Got new splitfires, new plugs, clean injectors. Still doin it. Is a Safc the answer? If so what are good ones for R33 GTS-T. Also just moved to Brisbanes Northside n am lokin for a good mechanic on this side of town. Anyone know any?? Cheers...