Poor Idle with Power FC???

[Steve]

Has anyone else had troubles with the idle quality of their car after fitting power fc?

Since fitting mine, it has a tendancy to hunt. Mainly when coming back in revs, and it will settle down after a while - but initially it is pretty poor.

I dont believe it is the decelleration fuel cut recovery rpm setting, as I have tried different settings with no avail. The car will idle smoothly if left long enough at idle, so I dont think it is the AAC valve either?

Has anyone else has had this problem, and had any luck with fixing it?

Cheers

Steve

[JimX]

I've got the same problem, although it is still better than the stock ECU. Sometimes it will die soon after starting, and I have to give the accelerator pedal a few pumps to get it to idle properly for maybe 10 seconds or so when cold. But it's not always like this when cold for some reason.

My idle setting doesn't seem to do anything either, the car seems to idle wherever it likes, and it changes every so often up or down. I might have a faulty idle control motor or something.

[SeD]

Ive helped a friend in the past with one and we've noticed and ive hear that if the wirring is not correct u can get weird results like idling at 3k... or almost stalling point. not sure bout the pfc but in the safc knoking signals can sumtimes b wrong..

[raist60]

Unrelated id say.

Shitty idle most likely due to 0/2 Feedback still being on, makes idle pretty crap turn that off and idle will be great.

JimX - Try altering your cranking inj times. I increased most temps in mine by about 5-10 ms and it cleaned up starting.

[SeD]

Unrelated id say.

Shitty idle most likely due to 0/2 Feedback still being on, makes idle pretty crap turn that off and idle will be great.

<----------------- how is this done??? how can u turn it off. soz dont know much about this topic but im interested. and finally how much can a PFC get picked up for brand new/ second hand

cheers

[Jimbo2000]

my idle is fine, not lumpy or anything but it is high, 1000rpm when at running temp, how do i fix that, i heard turning some screw at the back of the plenum?

should i just do that while looking at the pfc hand controller and stop when it gets to around 800rpm?

[raist60]

ETC - Function Select - 0/2 F/B Control and some kenji(?) jap characters for on and off

[JimX]

What are the side effects if you turn the O2 Feedback off? I'll also give that increased cranking injector time a go as well.

[Steve]

If you turn off your 02 feedback, it could result in worse economy.

02 feedback is used for closed loop running, such as cruise or idle - it will try and get the mixtures as lean as possible - AFAIK

I tried switching off 02 feedback, and it made no difference. This is something that happened as soon as the power fc was plugged in. with stock ecu it was fine. Cant run stock ecu anymore though, as I have injectors and afm upgrade.

[JimX]

Hmm, I can't see how your economy wouldn't suffer from turning that off. My idle isn't bad enough that I'm willing to sacrifice economy. I think I'll leave it on.

Maybe the O2 sensor is faulty? Or would the PowerFC detect the fault and give you a warning light? I'm sure mine is fixable without sacrificing economy, it probably just needs a professional to tune correctly.

[Steve]

Its not so much the idle that rapes your economy, its the driving.

The power fc does have a sensor check function, but I do believe that if an O2 sensor is just tired, it wont tell, only comes up as faulty if the sensor is broken, wire snapped etc.

[Guest INASNT]

I have a really bad idle problem which occurs at all different times. It will start surging from 400rpm to 2500rpm and after a while stall. I think mine is a vacuum leak somewhere coz it happened about a week after i drove with the pfc.

I havent driven my car for 7 weeks anyway, being built plus i am away for work, so hopefully i can sus the problem out when the new turbo etc finially goes on and i actually get to drive my car again.

[R33man]

After getting my Power Fc I noticed this a bit to. It does not idle as high when cold and then idles higher when warm. The factory ECU would idle at about 1400 RPM when cold and drop to 800 when warm. The FC idles at about 1200 RPM when cold but after about 30 seconds it drops to 1000 RPM and stays there. Ive also noticed it sometime varies its idle speed by 100 or so RPM. Not something I worry about but it just caught my attention.

[N I B]

This problem is easy fixed with the Datalogit and is very common.

[Steve]

This problem is easy fixed with the Datalogit and is very common.

If only they had Datalogit for GTSt:( So is that the only way to sort it??

[Guest INASNT]

Alot of these problems is also according to the pfc manual u r meant to let the car idle for like 30 mins from the first time you power up the pfc in the car.

But i dont think many people do this.

[51jay]

If only they had Datalogit for GTSt:(  So is that the only way to sort it??

Datalogit is now available for R33GTST apparantly for the time being you order for the GTR but specify it's for the GTST.

[JimX]

INASNT I did the 30 minute idle thing and it seemed ok, but then it started to have a mind of its own. Is there a way to reset the idle self-learning thing again without reseting the whole unit?

[Guest INASNT]

Dont know. I guess u can flash it and 0 all the setting but then u will need to tune again

[Steve]

For any interested, I just blocked my PCV valve, and now the idle has improved 1000%, when coming off revs, just hunts twice and then sits on set idle within 30rpm.

I acutally plugged the PCV because I noticed it was leaking a little the wrong way:)