Problematic Rb25det

[Benzino33]

Ok, where to begin?

I bought my r33 turbo last June and had a few problems with it. The car ran fine at first but had an idle problem and would stall in neutral when coming to a stop. Found out it was blow-by and a dodgy stepper motor. Fixed that,moved on. Was alright till the end of the yeah when I got a knocking noise when applying throttle, took it to the mechs but they thought it was lifers, in the end, we found the car had done a bearing and i decided to rebiuild.(done at CW) Rebuild gave me a forged long motor, but all the other parts of the engine were put back on. When I got it back, ran ok but not as good as I expected, then the engine started to misfire at idle and about 5000rpms. Fast forward 2 weeks, changed the coil packs and spark plugs(platinum). It seemed to fix everything nd the car ran perfect for about a week, then misfire returned, changed the coil packs again (under warranty) and changed the spark plugs to re-gapped ones (0.6mm). This was done when I took it for a dyno run and we found that the car ran extemely rich (it was off the charts), it would break down at high revs so we changed the plugs to the gapped ones. It didnt make much power on the run but the guy said he couldnt tune it coz it was a stock computer and would require a costly remap, or for a few 100 bucks more I could get a power-fc and that would fix it.

I didnt know too much about the car's history but knew it used to have a fmic,very lound and annoying aftermarket fuel pump, hi-flowed turbo and a pod filter. I have the feeling that the ecu would have probably been re mapped, but obviously didnt turn out too well. When I was at the dyno, the guy told me the car did have previous boost modifications but there were some underlying things he could diagnose off that ecu.

Also, a few days ago, I was driving and the car suddenly shut down, I knew the fueal pump had gone. I had bought a spare one months earlier luckily(Walbro). Chnaged it the next day and it ran alright but I'd find that at cold start it would hesitate when I'd go to third gear, also when I put it in neautral coming to a stop, it seems to hunt a bit to find the right idle.<br />Ok here's a run down of how its running today:

-Seems to have lost a lot of power

-Hesitates

-Loses power up high

-Runs rich

A lot of it is hard to explain but it's just not running right. I did change a few more parts over the course of owning the car. These include O2 sensor, Throttle body, TPS, coil packs and spark plugs.

Now I have decided that it just might be a faulty ecu, I'm looking to but one from here on the forum (an already tuned one).

What I would like to know is:

Will changing the ecu completely change how the car runs and fix the problems?

Am I better off just getting another series 1 stock ecu?

I feel like I've done as many physical mods to help fix this as I could

Sorry for the long essay, but I really do need to know what is going on with the car, I would really appreciate and input from any other Skyline owners. Has anyone else come across prblems like this?

Hope to hear from you guys real soon, fel free to ask any more questions. Thanks

Ben.

[Benzino33]

bump

[R33S2]

have you cleaned the AFM and the ACC valve?

[Benzino33]

<br />have you cleaned the AFM and the ACC valve?<br />

<br /><br /><br />

Ok AAC valve has been replaced and the entire unit cleaned out. I took out my AFm today and cleaned it out and dried it, put it back in. the car felt a bit more solid runnign but would misfire about 5000 rpm. I think i'll try taping up the coil packs to see if it does anything

[shaunvlc]

yeah id say your losing a lot of spark with the coil packs. try the tape job and see if that makes any difference. if it does take them out and put that high temp silicon around the casings for a more permanent/cheap fix. tape with heat will disintergrate in no time and your back to square one. however if its not the coil packs id be getting at least a afc to controll the air fuel mixtures. it sounds like its running incredibly rich to the point it affects performance.

[blind_elk]

Unless you are running monstrous boost levels, 0.6mm spark gap is too small. Open the gap out - I'd recommend 1mm.

[Ultimategtr]

Is it a series 1? The coils have been changed twice - and are brand new? if so then problem will possibly be elsewhere.. perhaps ignitors as they do tend to play up.

Hunting on idle - split vacum hose perhaps as well.

Something i advise everytime - reset the ecu and look for diagnostic codes.

[Benzino33]

<br />yeah id say your losing a lot of spark with the coil packs. try the tape job and see if that makes any difference. if it does take them out and put that high temp silicon around the casings for a more permanent/cheap fix. tape with heat will disintergrate in no time and your back to square one. however if its not the coil packs id be getting at least a afc to controll the air fuel mixtures. it sounds like its running incredibly rich to the point it affects performance.<br />

<br /><br /><br /

>Yeah at the dyno the fuel ratio was off the chart,,was meant to be at 11.2 or somethin but was at 9.5. I'll try the tape up job this friday and see how it goes, othrwise im gettin an ecu next week to see if it can adjust the richness. thanks for ur input

[Newy]

As far as i know, the fact that its running rich so badly will be fouling out your plugs? I'd swap in a stock ecu from a friend etc? see if it fixes the problem!? Also as people have said, try the ignitor, or even the actual coil pack loom itself. I would be highly supprised if it was the coilpacks if they have been replaced under warrenty once before with the same issue? If they are brand new there is absolutely no reason to tape them up, as they wouldnt be cracked...

[Benzino33]

As far as i know, the fact that its running rich so badly will be fouling out your plugs? I'd swap in a stock ecu from a friend etc? see if it fixes the problem!? Also as people have said, try the ignitor, or even the actual coil pack loom itself. I would be highly supprised if it was the coilpacks if they have been replaced under warrenty once before with the same issue? If they are brand new there is absolutely no reason to tape them up, as they wouldnt be cracked...

Hey man, i actually realised that the ecu i was runnning was a jap tuned one and was causing all my problems. bought a stock standard one yesterday and the car runs like a dream

[Newy]

Awsome to hear its running well mate!! problem solved haha

[Benzino33]

Awsome to hear its running well mate!! problem solved haha

lol yeah finally,,just gotta get it serviced and it will be perfect.

cheers