Weird Hunting Problem

[Cyph-R33]

Hey all, how's it going.

I've just recently picked up a series 2 R33 GTS25T, and I've got a bit of a weird hunting problem with it.

Basic symptom is the following: When moving the car just a little bit, be it in reverse or 1st gear, upon clutching in and braking, the revs will begin to hunt, going between 0 to 1500rpm, not necessarily that whole scale, eg it could go between 700 and 1500, or could go between 0 to 800, etc etc.

Perfect example of this would be in the drive through getting food at suchandsuch fast food place, when moving forward in line, so clutch in, first gear, bit of revs, clutch out, move forward the car length, clutch in before braking to a stop, and the revs will begin to hunt, or worse, it just plain stalls.. Will do this for about 30 seconds, and then come good. Giving the pedal a rev doesn't help this at all, it will continue to hunt after the throttle is closed.

Another example will be turning into a car park, full lock, clutch in and brake, engine will stall.

Idle is set at 750rpm. Is this too low?

Can anyone give any ideas for a solution?

Things that have been done:

CAS replaced, timing set correctly as per timing label on the bonnet (something like +15 btdc at 700rpm or whatever it is, it's been done as per the label).

Things that I will give a go and see what happens:

Clean the AFM with some contact cleaner (won't take it apart and touch the element, will just use the contact cleaner through the mesh or whatever).

If the contact cleaner doesn't fix the problem, I'll replace the AFM with a spare one that the workshop has, which they've said I can do, as I bought the car from them, free of charge.

Replace the plugs (probably should do it anyway, compliance place didn't do it as far as I can tell), and give it some good oil.

Apart from the above, intermittant problem, I've enjoyed my almost 3 weeks of Skyline ownership, such a nice car to have after having owned a fairly modified suspension wise S13 that was an absolute pig to drive on the road with its aggressive 2 way diff and all the fancy arms.

Cheers all,

-- Rob

[SECURITY]

rip off your AAC valve and give it a clean. before you ask any more questions about it, give the search thingo a go.

p.s. I'm going well, how are you going?

Edited December 16, 2008 by SECURITY

[shajar]

Hey Cyph-R33, I have the same issue, it has been playing up like that for 18mths now and I've just about had enough of it and ready to sell it as is...! Here is what I have tried I would like to here from you if you resolve your issue permanently.

-Installed CAI partition on Pod filter to stop hot air into AFM

-Replaced coil packs with known good ones

-Replaced Spark plugs

-Replaced Atmo BOV with plumb back OEM

-Replaced FMIC intercooler clamps

-Swapped out ECU with standard unit

-Cleaned AAC valve

-Check engine oil level

-Check coolant temp sensor for resistance at 80deg. (confirmed with infared temp gun) 324ohms

-Check voltage output from computer to sensor. Ok

-Check MAF for cleanliness- ok

-Check MAF voltage input, 5.2v ok

-Check MAF earth, 30mv-ok

-Check MAF voltage output ign on-.3v eng running- 1.7v ?

-Swap MAF with 2nd known good supplied unit - no obvious change

-Check fuel pressure idle cold-40psi, idle warm-35psi, idle vac hose disconnect-45psi

-Restrict return line and check for change in idle -ng

-Restrict supply line and check for change in idle -better

-Check voltage output from oxygen sensor -slowely max out to 1.2v!!

-Check back of vehicle while O2 sensor reading 1v- black smoke from rear of vehicle

-Replaced Oxygen Sensor - no change

-Disconnect both AAC and FICD valve and check if change in idle- ng

-Check power steering switch for malfunction, disconnect and check for change- no change

*remove PCV hose or oil cap and vehicle idles well.

-Check hose connecting from rocker cover to intake hose - ok

-Check hose connections between MAF and turbo intake - ok

-Checked for air leaks around inlet manifold- ok

-Checked for vac hoses being disconnected - ok

-Blocked all 3 charcoal canister hoses and checked idle - ng

-Checked for fault codes- none found - code 55 - system ok

-Adjusted ignition timming and set SAFC to zero correction and check idle- initally good but did not stabilize always

-Checked voltage to TPS- 5.2v - ok

-Checked voltage output from TPS -varying - ok

-Checked Air Regulator under manifold, measured correct resistance & not blocked

-Adjusted throttle plate stop, tps and iac bypass screw- see how it goes - still being a b1tch......

I'm just about to replace the CAS with a known good S/Hand unit but don't hold much hope for it fixing issue....alot of those tests above were done at a mechanic's workshop.

[bish33]

hav u still got stock ecu? do u hav aftermarket bov or is bov blocked off?

[WHITEBEAST]

I would say it could be the CAS (can cause these symptoms, intermittient stalling) would be a good choice for next atempt. sounds like it has been a big hassle for ya man, hope it all works out.

P.S. Don't sell it man!