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Hey everyone

I have a rb25 s2 motor in my skyline and i was on the track all day. I was driving the car hard however not on limiter but was around the 5000rpm mark regularly. Towards the end of the day my car all of a sudden felt very sluggish when i put foot down, so i pulled over and let it cool down for a while thinking it was just overheating. Took it for another spin but everytime i would flat foot the car doesn't pull and seems to be sluggish and the note of the exhaust changes and the noise of induction/boost seems to be louder than normal as if its under some load. If i however put my foot down very slowly then it won't be an issue and will run fine.

I checked my boost on my avcr and the gragh climbes as normal. Once on full boost the graph stays constant without any spiking so i ruled that out. I then also thought maybe it could be my AFM not working properly but when i remove the plug on idle the car try’s to stall and runs rich, so again i ruled that out. My other two theories are either one of the coil packs has cracked due to heat or something is up with my fuel pump. Im running a GTR fuel pump and the car is tuned to about 260rwhp.

Mods wise i got:

Rb25det

Stock ecu

Turbo back exhaust

Stock turbo

Apexi AVCR

Apexi SAFC ll

Pod filter

GTR fuel pump rewired straight to battery

That’s about it, i haven’t had a chance to inspect the coil packs yet as it happened today but will tomorrow afternoon.

I'm pretty certain it's a coil pack issue, what do you guys reckon?

Cheers ni

Edited by niran
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As i said, change the plugs.

Then see.

im with nismoid, check the plugs, could be hella dirty from the track day

also, check for boost leaks on ur piping, sure sounds like a boost leak

hey thanks guys, will check them out today in the afternoon and let ya know if that was the issue.

hey everyone,

I checked and changed the plugs and that didnt seem to solve the issue. I brought some Splitfire coil packs as there was some going cheap on skyaus. Installed them and it still didn't seem to solve the issue..

i then just started looking as sensors that may have been dud, i found one of the knock sensors had come out therefore i plugged it back in, took it for a run and it drives sweet again. Once i got back my alternator belt was squealing turned the car off and when i went to tighten it did i realize that there was no bolt.

I remember on the track before it happened i heard a noise as if a piece of metal hit the ground but was not 100% sure as i couldn't hear well with the helmet on.

i was thinking maybe some how that bolt came flying out and hit the side of the block, causing the knock sensor to come off also. Either way im glad its now resolved.

thanks for the help guys

Edited by niran
I checked and changed the plugs and that didnt seem to solve the issue. I brought some Splitfire coil packs as there was some going cheap on skyaus. Installed them and it still didn't seem to solve the issue..

this is a big fear of mine with my misfire problem. have been saving for coilpacks so really hoping the damn thins work!!

have tried all the bandaid solutions (taping, siliconing) with no luck

this is a big fear of mine with my misfire problem. have been saving for coilpacks so really hoping the damn thins work!!

have tried all the bandaid solutions (taping, siliconing) with no luck

have your coils bench tested. its not a big job

this is a big fear of mine with my misfire problem. have been saving for coilpacks so really hoping the damn thins work!!

have tried all the bandaid solutions (taping, siliconing) with no luck

hey man

yer i had the some thought of mine, but at the end ithought might as well use the splitfires as i will need them sooner or later anyway.

maybe before you buy some try some one else's coilpacks just to make sure that the coil packs are the issue

good luck man

Edited by niran
does the rb25det have two knock sensors? where are they? would mind checking as I have a similar fault in mine

hey man

yep the rb25 has two knock sensors. They are beside clyinder 2 and clyinder 5 on the block, if you look with a light you should be able to see the one closer to the front of the car, the other one however is a bit harder to see but shouldnt be to hard to find just feel around. Also they are on the side of the plenum and alternator

goodluck :whistling:

Edited by niran

hey i had this problem with my car a while back and i never found the problem i was giving it a bit going through the twistys in the dandanongs

all of a sudden i had no power and could not get over 70 ks i got realy concerned because there was not engin light , i tryed unpluging and re pluging the afm plug but it didnt fix it so in the end i just disconnected the battery let it sit for a few min's them reconected and hey presto back to normal and it hasent happend again (i also have all stock ) i think maybe the computer had a brainfart or something lol

hope this helps

it's really inconsistent tho. it has the usual miss on full boost (12psi) from about 3500rpm upwards, but also has a constant miss all through the rev range sometimes, with the tc bailing at the same time. good fun

Yeah My mates rb20det in his 31 is doing the same. We have tryed everything elce excepted coils.

Problem we are having is its a silver top with red top igniter and coils so we cant find any with the right plug to try

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