rb25det neo 4.2k rpm misfire/limit

[-Jo]

Hey guys, First post, ive been lurking for a while, i know there are plenty of thread on misfires, but the shoe doesnt quite fit. if there is a thread somewhere with a solution that i may have missed please link it and ill delete this?

Brought an 1995 r33 with 25det neo, with a few goodies, tuned on dyno to 213kw atw

engine details:

stock turbo (12psi), nistune ecu, adj fuel regulator, fmic, 500hp fuel pump, savage coil packs(they look pretty good), fresh spark plugs (bcpr7es pre set to 0.8), gfb boost controller, 3'' turbo back exhaust (no cat)

think thats about it the rest is stock

so my issue is when i test drove the car before purchase it reved up to 7k no worries, smooth no hesitation and smooth boost, now the car wont rev past 4200 rpm , makes no difference which gear im in or in neutral, cold and hot idle is mint, still boosts and drives fine under 4k. when reving to 4k it pops and misfires and will not rev higher, runs rich asf changed the spark plugs today and the old ones were black as.

also tried turning the boost down to 5psi to see if it would rev higher but to no avail

is wasted spark setup a possible solution? ive yet to look into it, if i dont need to i wont.

mainly want to know if this is something that i can fix on my end or i bite the bullet and send it to the tuners and hand over all my dosh lol

im no mechanic and im still learning all the little nitty gritty things, so any and all information is much appreciated!

 

[D0gg94]

Hey bro. Got a neo aswell and it sounds very similar to the issue I just fixed with mine. Only difference was mine didn't play up in neutral... try cleaning up your coilpacks and gapping a set of BKR7E's to 0.7mm. Ignition seems to be the first place to start with RBs as the coilpacks start clapping out under load.

Have a gander at this video and follow what he says to do with the coilpacks (Not necessarily the testing etc)

Its certainly the cheapest place to start.

Good luck man!

[-Jo]

Thanks for the speedy reply dude, i did suspect the coils, they are relatively new about 20,000kms on them, and still look as new, but i will pick up some of that goop and try that tomorrow hopefully, and will give an update on how it goes.

would i be able to take out my bcpr7es and regap them to 0.7? they have only been in the car for like 30kms.

Fingers crossed itll be just THAT easy to fix hahah 

Cheers

[D0gg94]

Yea just re-gap those bad boys. Maybe just give them a hit with carby cleaner if they're fouled up.

Hmm those coils do seem new with that mileage...

Well if you have no luck with this cheap fix, then you can start suspecting and ruling out other stuff:
Coilpack/s completely busted,
Possibly CAS,
Boost leaks
Etc...

Ignition is the usual suspect with misfires on rbs it seems but it could be heaps of stuff. Have you changed anything since it was tuned last? Or did this issue occur outta nowhere ?

OR did it occur after you changed the plugs recently ?

[-Jo]

sweet, the issue seems to have come out of nowhere, the previous owner took it to the tuners because it had a minor boost leak around the hks ssqv bov seal, tuner said it was sorted and i have re tightened all the clamps, i havnt vacuum tested ic piping for leaks yet, the issue is very consistent, doesnt matter how much throttle i give it (10% or 100%) so could i rule out boost leak?

might try get my hands on a new cas aswell and fix/rule that out

occured before i changed plugs, changing plugs has so far been my only try at fixing it 

cheers again for the help DOgg

[D0gg94]

All good brother.

Yea it does sound like ignition system, maybe make your way around the engine bay while you got the coils out and double check all your plugs and lines etc?

Cheap stuff first haha.

Neo cas's are like 600 bucks new so it'd be worth looking for a functioning second hand one somewhere perhaps or borrowing one.

If all else fails your tuner will probably be able to help you out with diagnostics.

Let us know how you go mate!

[-Jo]

Update: so i took the coils out, cleaned them and had a very close inspection of them and they look great, i put dielectric compound on the boots anyways, cleaned spark plugs and re gapped them to 0.7, with the same compound on the tips of them.

i also unplugged and sprayed electrical contact cleaner on every plug i could get my grubby little fingers on.

still does the same thing.

i did notice on the coil plug of cylinder 1 (closest to radiator) a part of the little plastic surround is missing (see pic) surely this isnt whats giving me troubles?

ive also included a very short video of it misfiring, hopefully this will give you an idea, using about 20% throttle in vid

if u guys need anymore information or a better video while driving, please let me know, i wanna help u to help me!

Thanks 

 

 

[tridentt150v]

If it ain't blue its poo!!!

The only direct replacement coils that work other than standard ones are Splitfires.  Most of the yum cha specials on the market seem to have reliability issues.   But you won't know until you swap them out.

 

[-Jo]

If i get my hands on a multimeter and test each coil, what sort of resistances will i be looking for? 1.6-1.9? 

or i can idle the car and remove coils one by one to see if anything changes, but the car idles fine would this test still be effective/ accurate?

[Ben C34]

Theres no point testing with a meter. Those red coils are shit

[GTSBoy]

Just the fact that they are red means throw them as far away from the car as you can and don't go looking for them  They are more shit than a pile of shit.

[-Jo]

its yet to be confirmed the coil packs are the issue, but more than likely, it seems a bit overkill to go straight to spitfires? whats the general consensus on buying 2nd hand coils, or even converting to toyota yaris coils, im not after big power but i do have plans in the future to high flow my turbo and more supporting mods and try for 250ish+kw atw

thanks for giving me some things to research into guys, i really appreciate the advice

 

[GTSBoy]

Why is it overkill to go straight for Splitfire?  They are the only option other than the original coils, for coils that are the same form factor.

Yaris coils (or any other similar Toyota Denso coil) are good, but not a lot stronger than Splitfires.  If you can get them for <$90 each, then they make a reasonable upgrade, but you still need to mount them and adapt the wiring.  There are links in the trader section here for kits using Audi & R35 GTR coils that are even better options, but generally at quite a lot more $$ than Splitfires.

2nd hand coils are a lottery.

[-Jo]

i just wouldnt expect fairly newish coils to cough out, but i understand what ur saying, spitfires are quite expensive, but a worthy investment, and 1 less thing to worry about right.

i will call tuner tomorrow, and hear his opinion, and probably take it in, in the meantime i will shop around and see if i can get a good deal, i suppose no one sells good working 2nd hand spitfires, as not many people upgrade from them.

cheers gtsboy

[-Jo]

hey so might have found the reason why it limits in neutral (or more accurately while not moving), the tuner said it has launch control, tuned into the nistune ecu, set to like 4500rpm, so what u see in the video may be that.

ill be borrowing a mates set of spitfires from his rb25/30 tomorrow night or the day after and will chuck them in and see if it is rooted coils.

i was also recommended an awesome website that sells pretty much everything jdm, with really good prices to match.

www.rhdjapan.com anyone brought anything from these guys, if not at least check out the website and let me know what u think.

[GTSBoy]

Everyone here knows RHDJapan.  They're good.  You also want to look at Nengun, Amayama and even JustJap.

[-Jo]

borrowed some spitfire coils from a mate and now my car runs mint!! YUSSS

thanks heaps for all your help guys/girls

if theres one thing ill never forget its this saying hahah

On 12/16/2018 at 2:39 PM, tridentt150v said:

If it ain't blue its poo!!!

 

 

[GTSBoy]

Good result.  Another entry in the "it'll be coils before it'll be something else" file.

Surprise finding on the launch control.  Looking at the video (just now), it does sound & behave very much more like a deliberate misfire (ie launch control) than a shitty coil misfire.  There's nothing better than having 2 things going on at the same time to confound your diagnosis.

[-Jo]

yea im surprised it had launch control, previous owner mentioned nothing of it, wouldve thought he'd use that as another selling point.

but sorry for wasting your time man, if i had more experience i would have known it was coil packs, but new to rb's, thankfully its something simple like that.

should this thread be deleted? as there are already plenty of threads very similar to this

[-Jo]

so had no issues with misfiring yesterday.. but its bloody back misfires at 4.5k rpm then starts to climb revs again ( i always button off when it misfires, try to treat my car with tlc) , even with new spark plugs and ive still got spitfires in them

can someone confirm for me that the only other thing it could be is either boost leak or cas?

just love owning and rb so far...