High RPM problem.

[ZERO]

Hi Guys i got a problem with my car reving past 4-5 rpms... it starts to splatter... sounds like the pistons is goin to blow out of the block...

R33

RB25 DET

slight mods

- airfilter

- 3 inch all the way

- 9 - 10 psi.

only started not too long after i installed a FMIC.

also my fuel lid isn't pressurized. the seal is cracked would this do anything?

also just had a full 80K service.. all new iridium sparks still not sure why its doin this...

[Doctor 30]

stuffed coil packs maybe?

[meggala]

i bet the peeps who did the service didnt gap the plugs properly to .7 or .8

msot of the time they forget and jsut put them in

meggala

[ZERO]

how do i check the coil packs?

and i'm pretty sure the plugs are pre gapped.. the box said it was pre-gapped at .8 i think and advised not to gap it any more...

[sewid]

ecu overboost protection. same as a lot of people on the forums. time for a ecu upgrade.

[ZERO]

OH MAN i really hope its not that man... can't afford a new ECU now.... dont want to either just want to fix the damn problem...

you guys reckon i'm leaning out or something?

[ZERO]

any one know who i can goto to get it checked out?

[Zahos]

so i guess you didn't bother, and can't be bothered to search....

here you go: http://www.skylinesaustralia.com/forums/sh...ead.php?t=51046

[ZERO]

- Even one cracked coil can cause a lot of hesitation!

- i was getting it between 4500 - 5500 rpm, and after that it was all good, it would rev out nicely...

- When i taped mine the problem went away, but after a week or two, came back b/c the tape shrunk on the coils, exposing parts of the crack once again

- I would be doing this to ALL of the coils, regardless of wheather there is a crack there or not, as it could crack soon anyhow as the others have....

umm... this sounds like wats happening exactly..... (4500 - 5500 rpm) but just a question wat is hesitation? its not like back fire is it? not poping from exhaust right?

[Zahos]

Yeah, that's what I was implying with that post. It pops, and misfires at around that point at WOT.

Even if you fix your coils, at higher boost, best case scenario is that instead of popping and misfire, you will get a flat spot at around that point.

You will need a new ECU, or a SAFC to retune your air to fuel ratios, as they get VERY rich at around that point with higher boost. I think that timing gets retarded too b/c of the overfuelling, hence the massive flat spot / misfire.

Even with a SAFC, b/c it runs leaner after a tune, the timing does not suffer as much. I only have a SAFC, and I have NO flatspot. In fact, where the flat spot used to be, there is actually a tiny surge or power.

Below is a pic of my dyno graph before and after the SAFC. (Note on the first run - green, my tuner backed off b/c the A/F ratios went crazy. Then sensor he was using to measure the A/F ratios was buggered and he replaced it after a couple of runs.)

[ZERO]

nice... power run man...

hmm.. mite just give the coils a check first... see if that is the problem... need to get this done asap and dont wanna spend much on getting a p fc and all that man... spending too much on it already...

[Sime]

Hey Zahos

I am running 12psi and have an SAFC2. It been running great for months. Then on the weekend the car developed the same misfire you guys are talking about. popopop at around 5000rpm and a short drop in power. When I dropped the boost to 10 psi, the problem went away. The spark plugs should be fine as they are new. Would this be a sign the coil packs are on there way out?

[Zahos]

it could be, but it's just one of those things you woould have to investigate.

It sounds very likely though.

And that is exactly what happened with me, except i was running 9 - 10 psi to begin with.

[nizmokid]

the coil packs must be a weak link in the r33 skyline!

[cav]

explain a SAFC has any body fitted split fire coils. i have same problem, and series 2 coils are different.