Jump to content
SAU Community

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


Recommended Posts

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 !!!

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 :P

  • 2 weeks later...

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!

  • 1 month later...

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

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.

  • 2 months later...

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 by VLT025

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.

^^^ 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...?

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 by 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

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

  • 2 weeks later...

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...?

  • 2 weeks later...

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.

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

  • 4 weeks later...

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
:rofl:

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...

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

    • Major thread necro but how bad of a job is it to DIY? Looking at it online it looks like if you reuse your ring and pinion as long as those are in good condition it should be fine to just pull the axles/front cover and replace the diff that way? Or should I be replacing everything and doing preload measurements/gear mesh testing like the factory service manual mentions for the rear diff?
    • in my list I had the R33 GTR as the best Skyline. Infact I had all GTR's (33>34=32), the NSX, the GTO, the 300ZX, the 180SX, the S15 better than the FD RX7. I had the MR2 and the A80 as 'just' better. I also think the DC5R Integra looks better but this is an 01 onwards car. I also think the FC>FD. It's almost like aesthetics are individual! The elements @GTSBoy likes about the FD and dislikes about the 180 are inverse in my eyes. I hate the rear end of the FD and it's weird tail lights that are bulbous and remind me of early hyundai excels. They are not striking, nor iconic, nor retro cool. The GTO has supercar proportions. I maintain these look much better in person (like the NSX) especially with nice wheels and suspension which is mandatory for all cars pretty much. Some (or all) of these you have to see in person to appreciate. You can't write a car off until you see one in the flesh IMO. Like most people we probably just like/dislike cars which represent certain eras of design or design styles in general. I also think the 60's Jag E type looks HORRIBLE, literally disgusting, and the 2000GT is nothing to write home about. FWIW I don't think the Dodge Viper Gen1's have aged very well either. You can probably see where I rate bubbly coupes like the FD. I know we're straying now but the C4 and C5 absolutely murder the Viper in the looks department as time goes on, for my eyes. Wouldn't surprise me if people who love the FD, also love the MX5, Dodge Viper, Jag E Type, etc etc.
    • I used to hate R31s, and any of the other Nissans that led up to it, and any of the Toyotas with similar styling, because of the boxiness. They were, and remain, childish, simplistic, and generally awful. I appreciate R31s a lot more now, but only the JDM 2 door. The ADM 4 door (and any other 4 door, even if they are unique compared to our local one) can eat a bowl of dicks. The Aussie R31 is also forever tarnished by their association with stereotypical bong clutching Aussie R31 owners of the 90s and early 2000s. I think the Nissans of the 70s (other than 120Y/180B/200B) are far superior looking to the 80s cars. The 240K era Skylines are boss. The same is broadly true of Toyotas. Hondas don't ever register in my thinking, from any era. Mitsus are all horrid shitboxen in any era, and so also don't register. Subarus are always awful, ditto. Daihatsus and Suzukis also don't generally register. They are all invisible. I think the SW20 MR2 looks fiddly. The 3000GT/GTO is like that but way worse. Too many silly plastic barnacles and fiddly gimmicks ruined what could have been a really nice base shape. Kinda-sorta looks like a big heavy ST165 Celica coupe (and I'm not sure if that's a good thing or a bad thing). I think the 180SX is dreadfully bland. It's not bad looking. But it has no excitement to it at all. It's just a liftback coupe thing with no interest in its lines, and bad graphical elements (ie wide expanses of taillight plastic on the rear garnish). The S13 Silvia is a little better - getting closer to R32 shapes. But still....bland. S14? Nope. Don't love it. S15...a little better. Probably a lot better, actually. Benefits from not being like a shrunk in the wash R34 (where the S13 was a shrunk in the wash R32 and the S14 looked like a Pulsar or something else from the stable on Nissan mid 90s horrors). The Z32 was hot as f**k when it came out but hasn't aged as well as the A80. Keep in mind that I think the R33 is the most disgusting looking thing - and out of all the previous cars mentioned is objectively closest to my precious R32. It's just....real bad, almost everywhere you look. And that is down to the majority of what was designed in the 90s being shit. All Nissans from that era look like shit. Most other brands ditto. In that context, the FD absolutely stands out as being by far the best looking car, for reasons already discussed. Going behind the aesthetics, the suspension alone makes it better than almost any other car.  
    • If they just called it the "Mazda Tiffany", it would have been spot on.
    • Yup but for me its the HR ! Cut my teeth on the old holden 6s in the day ! And here's me thinking in the day it was also the 300ZX and the Mitsubishi GT3000 ! All, as well had good lines, but always seemed to need finishing off, style wise.
×
×
  • Create New...