Another R33 Idle Hunting Thread

[Touge Kyousou]

Hey SAU,

Couple of days ago i picked up my r33 gtst with a second hand motor as i blew the previous motor again.

Car is running perfectly except it idle hunts on clutch in.

What will happen is cold start is fine, then once the temp hits normal, drive then clutch in and the revs will go to 2k for a brief moment, then drop to 1.5k where it hunts between 1k and 1.5k, after a random amount of seconds, the idle will then smoothly move down to 850rpm and stay there. Once it hits 850 rpm it will stay there till next take off/clutch in etc. Note it never goes below 850rpm.

I have searched and found the aac issue so that's been cleaned but didn't make a difference unfortunately. The car did sit for around a year until i got the engine swap done but was started a few times to prevent things clogging up like injectors etc.

I did find some stuff about apexi PFC idle learning but i don' have datalogit so can't perform the procedure without losing my tune.

Would the pfc need to perform the idle learning procedure as the engine has been swapped, even though all mods are the same ?

Car idled perfectly for the last two engines and i know the previous engine swap had the ecu retuned as it got moved to e85 then.

Mods are

apexi pfc

garrett gtrs

intake, fmic, z32, coilpacks, copper plugs, tbe,

740cc injectors

That's about it that would affect idle.

Thanks

[ARTZ]

Man I have exact same issue...got me stumped for a while...it had issues with startup that were played with on the weekend and it made a big difference to the cold start especially ,that I would say it's no longer an issue.. But soon as I drive it and pull up at traffic lights ,bang 2000rpm...drops and bounces between 1-1.5 then after 30seconds or so of this it drops to normal.idle...problem is sometimes it will take minutes before it settles and you get funny looks from cars beside you as the revs bounce around....I'm just waiting for a cop to pull up and ask wtf is going on with my car...

it probably does this 90% of the time and it seems to be more pronounced on e85...on pulp it is rarely an issue but still happens..As you say it only happens after a drive too..if I start the car on the spot the idle is usually fine..drive 20mtres clutch in and there it is again...

For a while I noticed that if I would start the car let it warm then disconnect the aac top plug it would be fine. (Though this is not something you want to do everytime you drive). But after a while this bandaid solution fell off anyway and it was hunting yet again..

I am running an Adaptronic with inbuilt MAP fwiw

Suggestions have been made around latency issues or a return to idle issue, but I'm still not convinced its just not something mechanical..

[scotty nm35]

Have you checked the TPS yet mate? Stick a meter on the wires and make sure it drops to .45v or whatever is recommended.

[Touge Kyousou]

Hey guys,

Thanks for reading and answering my thread, much appreciated

I returned to my original mechanic today as he asked me to swing around so he could have a look at it and it was fixed in 5 minutes huzzah!

Artz,

What you described is bang on with what was happening with my car. Anyways, last night i cleaned the aac valve as per this thread: http://www.skylinesaustralia.com/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/page__st__100

Took the car to a workshop today and after 5 minutes playing with the idle screw on the aac valve/housing, the idle no longer hunts! We basically just let the car warm up, then turned the screw to one extreme and work back and forth from there, testing now and then with poking throttle then back off, touch the brakes and clutch in. Maybe worthwhile cleaning the aac too if you by chance haven't done it ?

Hope this helps and your problem turns out as simple as mine.

[Badcredit33]

Mate ill put my 2c worth in here, I had the exact problem as well but I was running stock turbo. Had pfc tuned and started hunting allllll the time cold hot whatever so I played with the AAC valve and it sorted it but only for a little while then it all started again.

Anyway, got a gtrs and 740cc injectors exactly as u have lol and had it retuned, any now I have absolute perfect idle 100% of the time.

So I'm guessing u may have an issue with ur tune (maybe not) but that's just my experience anyway.

Good luck