Power Fc Fluctuating Idle

[Drift Freak]

I've just got my R32 GTST tuned on the weekend and at idle when its warm it "hunts" up and down from 900 rpm to 1100rpm, has anyone else had this issue or is it my tune????

Also does anyone else have AP Engineering Power FC with the optional boost controller hooked up and working. I hooked mine up as per PaulR33's FAQ but when my tuner was tuning it he couldn't get it working and i had to use a manual bleed valve

Any help would be great

Cheers

[munro'sgts-t]

well i cant answer your question bu tmy car does this to but i hav an apexi safc and it does it between 500 and 1100 nearly stalls. from what ive noticed is it normaly happens when my intercooler hose clamps are loose maby worth cheking. other wise i have herd that the acc valve gets dirty and gummed up and causes this to happen as well i think its real name is air idel control valve or sompthing around those lines.

[Drift Freak]

Cheers mate, i did tighten all the cooler pipes about a month ago but its worth checkin. I cleaned the ACC valve about 6 months ago so i should probably check that also.

Cheers mate

[munro'sgts-t]

hope it works cos i no it gives me the shits when i starts to run like a rotary or sumpthing tha thas sum huge cams in it lol. but yeh fmic suk for that i thikn its just bad clamps on mine and all the bumps and vibrations on the road. le tme no if it works hope so

[BAMR33]

Up the revs on idle, with stock settings it's too low. Mine only idles smooth at 750rpm. And on start up it idles at about 1000rpm.

[SimonR32]

atmo venting bov?

or standard bov leaking?

[NYTSKY]

3 ways to fix it.

1) self learn again

2) add fuel to your idle

3) buy a new ACC valve ( thats what i had to do but i just put in a second hand GTR one)

[Drift Freak]

Cheers guys 4 the replies. I'm in the process of buying a turbosmart adjustable atmo BOV hoping it might fix the problem. Will try the self learn after i fit the BOV, hopefully its not a major issue. Thanks for the replies guys will look into each of them.

[BAMR33]

There's only one thing that has changed - The tune. So chances are it's not going to be the aac, BOV or clamps because these were functioning fine before. Richening up the idle is more than likely going to make it worse as more fuel was probably already added at idle, even if it wasn't it's just stab in the dark.

I wouldn't bother with self-learn again, just try bumping up the revs little by little until it idles stable. Optionally get your tuner to jump in the car on a hot day (worst for stable idling) and get him to do a street tune for economy and to fix the idle. It's far better than the fake conditions generated in the dyno tune.

[Drift Freak]

Cheers BAMR33, thats what i thought about the ACC and clamps. Will try adjusting the idle up. Am thinking about bigger injectors and Z32 airflow meter so i'll see my tuner when that comes around.

Cheers

[sinistaGTR]

ok do the self idle and get it retuned.......i had this prob and when i got a retune we did it and worked sweet

[R31Nismoid]

putting on an ATMO BOV is going to require a retune most likely.

turn off the O2 sensor.

Its mostly likely faulty and causing the problem you are having.

Mine did it after we stuck the PFC in for the first time

[700HP-GTR33]

putting on an ATMO BOV is going to require a retune most likely.

turn off the O2 sensor.

Its mostly likely faulty and causing the problem you are having.

Mine did it after we stuck the PFC in for the first time

Mine does it at cold start.....and it hunts up and down until warm.

So could be oxy sensor then...or acc valve...suppose I need to clean it and check.

[paulr33]

Please confirm the checkpoints below

Has the initial idle self learning process been performed? Has it been completed?

Are the settings for the airflow meter, air cleaner correct? (Some air cleaners from other manufacturers may require setting adjustment. Also, individual vehicles may also require minor adjustments.)

Is the setting for the boost control kit incorrect?

Is the deceleration recovery RPM correct for the engine?

Has the coolant warmed up adequately?(In winter or in cold regions, the low water temp correction feature causes the idle to rise. There may be a delay until the coolant reaches a normal temperature.)

If the idle is not stable after checking the points above, please try the following.

Unstable Idle Correction-1

Use the Idle Adjust Screw(Nissan :AAC,Toyota:ISCV)to change the amount of auxiliary air.

Since the idling A/F will be unstable regardless of being rich/lean, set the A/F to around 13.5 - 15.

Unstable Idle Correction-2

Set the idle higher than the target idle for vehicles equipped with upgraded camshafts or engines with modified valve timing that creates a lot of overlap. Also, be sure to set the fuel cut RPM about 400RPM higher than the target idle RPM.

For vehicles equipped with lightened flywheels, unstable idle may persist because the flywheel causes the engine RPM's to rise and fall at a much quicker rate than normal. The idle self learning may not be enough to compensate for the amount of auxiliary air. In this case, set the fuel cut return RPM 100 - 200rpm higher and try to adjust the amount of auxiliary air through mechanical means.

Unstable Idle Correction-3

An engine with a modified displacement or compression rate will require more air at idle than factory settings. If the idle does not stabilize despite performing the steps above, it may be necessary to enlarge the hole diameter in the mechanical components (Nissan:FAAV, Toyota:FISCV)to adjust the auxiliary air amounts.

[Spook's_Skyline]

does your idle hunt all the time?

somedays mine is perfect, others its all over the place

seems to be if you are giving the car some stick, then it tends to be more likely to idle all over teh shop

doesnt overly bother me, so i havent done anything about it