Rb25Det Problem

[lawler]

Well my rb25det in my r32 is playing up.

Its idling fairly rough. Randomly starts hunting at idle then will just go back to being rough.

Bit rough cruising bellow 2500rpm

Pinging up top. Its only running 9psi with gcg high flow on 98.

It pull to red line smoothly but not aswell as it should but every now and then it gose like it should.

Allready tryed another afm and with afm unpluged so it runs off base map. Cant find vacum leak. Tryed running it with o2 sensor unpluged so its on base map.

[Jeremy93]

Assuming you have a standard ecu. Remove that turbo and put an rb25 stocker on.

[lawler]

Was having same problems befor swapping turbo. I had the gcg sitting there and mate need a turbo so i swapped it on

[ARTZ]

yeah the problem is you're not revving it hard enough..when ever you install a bigger turbo with a stock ecu the trick is to hold it at redline for at least 5 minutes so the ecu can learn the new maps....

Try it and we won't be disappointed.

[lawler]

Sorry im not retarded.

Im just after idea of what i might have over looked. Compression is good with bettwen 165-175psi on a fairly cold motor. Plugs and coils are good. Can notice a change when any coil is unpluged

[Bitsushiti]

Check those hose clamps, joiners, hoses and vac lines on all intake, cooler piping, boost controller, BOV, brake booster, rocker cover breather hoses, PCV system etc again. Check all of them. Anything with a bendy black thing attached to a solid something and a silver/gold clampy thing holding it there. If you have a mechanical boost gauge, even check the line going into the back of that and the point where it goes through the firewall too.

I can't stress the importance of this enough... it could save you from hours of pulling your hair out and spending hundreds of dollars chasing ghosts. I once had a wormdrive clamp that was an absolute bitch to get to and would only play up once engine warmed up to operating temp, eg. intermittent lean misfire and rough idle, rough performance at low rpm. Even with a vac/boost leak tester I made with 18psi pressure applied it wasn't obvious. It drove me insane for about 2 months in which time I literally tore my whole engine bay apart, spent hundreds and replaced heaps of shit that didn't need doing. I ended up feeling pretty stupid when I discovered a single twist of a screw on a $3 hose clamp was all that was needed to solve my problem. On the upside I learned a ton about how an RB ticks and there's heaps of shit that won't need attention for a long time... lol.

IAC / AAC valve - likely to have 15+ years of junk in it. Refer to this: http://www.skylinesaustralia.com/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/

Throttle body - it wouldn't hurt to give the TB & butterfly a good clean too (while you've got the carby cleaner handy from your IAC/AAC valve cleaning session ).

Mass Airflow Sensor (AFM) - remove and give it a good clean. Don't use carby cleaner on this. Use dedicated mass airflow sensor cleaner instead, it's not a solvent.

O2 sensor - if your ECU is relying on it (standard ECU does afaik), remove and clean, if really shitty, replace it. If o2 feedback isn't required eg. aftermarket ECU tune, ignore this.

Fuel Filter - it'll cost ya about $10 for a new one. Ryco Z200 fits like a glove and is a bit longer which is handy if you need to trim a bit of fuel hose back to get the old one off. If it hasn't been replaced for a long time I'd get onto it, I've seen some horrific shit come out of filters that have been left unchanged for 1+ years.

In uncommon/rare event - Knock sensor/s - if your ecu can't get a reading from them, it'll richen your map up and retard the timing. Inspect 'em.

Hope this helps

Cheers

[lawler]

I accaly pulled the whole inlet manifold off last night and replaceing gaskets and every vaccum line.

Im thinking its not knock sensor because rich and retarded timming would mean it wouldnt be deternating up top