R34 Gtt Variable Miss...? Help And Advice Please.

[markimak]

we just got the R34 GTT and on inspection before buying it had a slight miss which she then took it away and put some fresh set of plugs in (unknown brand or gap). the mechanic who did the work for her said plug no.4 was rich and had carbon deposits... all 6 wer supposively replaced.

it was better but could still feel a slight miss up high. it gradually got worst till today driving around it wouldnt rev over 4500rpm.. just occasionally. and another time u can hear it miss on idle and at 3000rpm onto the highway. (it used to rev through fine without load. but when loaded it will miss now it misses all the time..?)

now im guessing its to do with the plugs.. wrong gap. bad plugs..

coil packs. i understand coil packs do this often.

AFM or sensor. (O2 sensor)

Fuel related (blocked filter)

any other suggestions wher i should go hunting..?

thanks for all ur help in advanced.

car is tiptronic '99 model with <50,000kms and cat back exhast and pod. (is my brothers car and he likes the pod and noise. personally i think the airbox is adequate)

thanks

mark.

[WogsRus]

Dam mate, there are so many topics on this,

FIRST, get a set of new copper plugs, i have an R33 and run BKR6EYA, the others don't work for shit in my car.

Gap these to 0.8mm

I have just finished with my car, and still having problems.

It is also most likely a weak coil, and if you do a search on " how to cure missfire"

sorry but that's my contribution. i just got back from the garage so time for bed.

[Wheezy]

BKR6EYA are already at 0.8mm unless they are -11

[markimak]

thats cool.

im well aware of that. thanks mate.

but thanks for the part numbers..

just wondering wher i should start digging. and if ther is any other contributing factors that may relate to the missfire..

[Abo Bob]

I'm 95% sure you need new coilpacks. The symptoms are the same as mine and many other R34 owners. See it too many times.

[markimak]

recommend using the silicon and basting them in it?

i guess it couldnt hurt to try it..

also is it not recommended to mix and match just replace the coil pack that is rooted.?

i also have a feeling it will be No.4 thats worst off due to the carbon build up on the plug.. will check them this weekend and post up.

thanks

mark.

[Abo Bob]

Most people stuff around and end up replacing them all.

[666DAN]

Get some splitfires and feel safe in the knowledge they will never bother you again

[markimak]

600.. think its still worth a try with the silicone..

thanks

mark.

[markimak]

ok

pulled them out 2 nights ago upon inspection none had vissible signs of cracks or marks.. so i decided to bast them with silicon 401 as a DIY thread suggested. waited a night and put them in.

started it up warmed her a bit. and took her for a drive still had miss. but it was more upwards of 6000rpm.. had more lower down torque. but still wasnt fully driveable.

parked it in the driveway.. gave it a free rev held it at 4k to see if it would splutter. and it didnt. then took it for a drive again and it was better. came back. decided that i would try to cool the intake temps to limit chances of detonation.. so i threw some cold water on the SMIC and took her for a drive. revs fine all the way to 5500 and cough and then to redline..

after a while it ended up fixing itself..

now my guess is the ECU adjusted itself a littlebit as it went on. or due to lower air temps ther was less pinging and it helped out. thus cleaning out any hot spot carbon deposits from the head leaving it clean..

sound right..?

so all in all. cost me $13.45 from true value and a cup of water. better than $600 splitfires. hope it doesnt come back..

[Adriano]

I doubt that, i would check for trouble codes, clean the AFM and check fuel pressure under load. Also check your catalytic converter by banging on it, if it rattles, then its stuffed.

[markimak]

nah it runs perfectly fine now. im just wondering if the ECU slowly redid itself.

[Adriano]

Good to hear its fixed, the factory computer doesn't have any self learning, and i cant see how a cup of water will do anything. Its still possibly the cat converter, sometimes they lodge and dislodge themself, blocking and unblocking the exhaust. Has it had a fuel filter done?

[markimak]

brand new cat 1000-3000kms old..? exhast is 1000-3000kms old soo. i dnt knw.

i still think lowering the intake temps with the water kept it cool and allowed itself to clean the engine of the excess carbon hot spots..

either way. problem fixed.

+1 for SAU DIY THREADS

[Tangles]

+1 for SAU DIY THREADS

Yup!! Got my new sparkies, and wondered where the hell they go in the RB25det, LOL!

Good ol DIY FAQ threads showed me the step by step procedure, and also the Silicone 101 trick, trying it all out tonight / tomorrow (dont have miss, but dont want a miss fire to develop when next tuned at 1bar)

[markimak]

year RBs are a bit whacked to do sparkies on.. RB26 aint bad.. but turbos on RB26 are

if anyone in brisbane wants me to do ther coils for them let me knw..

[Tangles]

OK - took the day off today to have a nice 4day weekend, why not, lol.

Changed the sparkies from 1.1s nonamebrand to ngk copper BCPR6E pregapped to .8mm - knee has blown up like a watermelon tho, lol, damn you kneecap-less kee Its hard being over 2m tall with sore back/knees bending and undoing stuff-knows what to get at the sparkies

Used the 401 industrial silicone sealer on the 2 longest sides of the coil packs (S2 rb25det) - query is should I put silicon over the two ends, one end is black plastic the other is see-thru plastic where you can see the electrical mumbojumbo stuff behind. Or should I then wind all the way around some good electrical tape (so its got the seams sealed with silicon and the ends wrapped in tape)?

[markimak]

i put it on everywher that is black apart from the tube and the metal mounting points.. even though i saw no cracks prob should seal it anyway. just seal the sides that is to sit near the block as it will try to arc out thru the crack to the head.

[markimak]

ok..

i havent driven it but i was told it was still ther.

my brother started it warmed her up and she started to miss..

any idea?

shes still running the same copper plugs that the old owner put in.. 500>KMS ago.

ive sealed coils. and it worked fine for a day.. what is it now?

[markimak]

yeah still ther. but spray water on the smic and go for a drive and its gone apart from changing gears.

fuel pump/ filter maybe?