R33 Air Con Idle Fluctuation And Stalling

[macaroni646]

Hi guys,

When I have the air con on and stop at a set of lights, the idle fluctuates from 500rpm to 750 and continues to cycle like this until I get going. If I clutch in and let the idle dip, sometimes it stalls.

The car's tuned on a Haltech platinum pro and everything's stock besides exhaust.

What could be causing this and how can I fix it? Should I adjust the idle abit higher?

Normal idle is 750rpm.

Cheers

[SargeRX8]

Does the car run absolutely fine with the AC off? If so then there is a chance the car was not tuned to compensate for the AC being on. I know the Apexi PFC has an autolearn feature to set this up for you and control the engine when the AC is on or off, not sure how it goes with the Haltech but the same principle should apply.

As long as the car runs fine with the AC off, I'd be looking at the tune since the compressor will throw out the load tables and could affect your idle.

[macaroni646]

Yeah runs fine with AC off. Should I turn up the idle abit and see if it balances it out?

[SargeRX8]

Try that since thats an easy approach but I believe what that will do is fix the stalling due to higher idle but won't affect the hunting.

[HYBRID VL]

is it like this mate.

[macaroni646]

Yep exactly like that. I read on the Haltech forum that it's very common. Happens to you too?

[HYBRID VL]

that is my R33 doing it cleaned my AC valve and it hasnt done it to that extent since.

Maybe give that a clean see how you go it fills up with crap over the years might help there is a DIY cleaning post on here If i CBF id link it but yer just search bro and you will find it.

[Hadouken]

I had this same problem on my 33. Once with the powerfc and then the same with a Link ecu. Problem was the tune. All that needed to be done was the idle had to be slightly raised through the ecu. Problem fixed and never stalled again.

[HYBRID VL]

im using the stock ECU only mods on my R33 atm is a pod filter and 3inch cat back exhaust...though my mates S15 is doing the same thing and he is using a Power FC

[macaroni646]

UPDATE: Problem fixed by cleaning AAC valve as Matt suggested.

[Dose Pipe Sutututu]

Does the car run absolutely fine with the AC off? If so then there is a chance the car was not tuned to compensate for the AC being on. I know the Apexi PFC has an autolearn feature to set this up for you and control the engine when the AC is on or off, not sure how it goes with the Haltech but the same principle should apply.

As long as the car runs fine with the AC off, I'd be looking at the tune since the compressor will throw out the load tables and could affect your idle.

partially correct, however there are 2x idle settings for the PowerFC.. 1x is idle without AC and 1x is idle with AC on

many tuners somehow always forget to set this correctly, especially when cars run aftermarket cams and you often see them stall at lights.

[shubby0901]

Hey, ive got the same issue. The revs do not fluctuate as much but the car is rough while standing still. It doesnt stall as I have done the cleaning of the AAC valve. This only happens when the air-con is on.

[Dose Pipe Sutututu]

Hey, ive got the same issue. The revs do not fluctuate as much but the car is rough while standing still. It doesnt stall as I have done the cleaning of the AAC valve. This only happens when the air-con is on.

What ECU?

[Hadouken]

I had that problem on my powerfc and link ecu. Both were tune related

[shubby0901]

What ECU?

Whoops I shouldve mentioned. Its a stock ECU. Car has stock exhaust, stock BOV. No performance work done.

[Dose Pipe Sutututu]

perhaps your idle valve is set too low, try this...

unplug your TPS connector

unplug your idle valve connector

then adjust the screw till your car is at 800rpm

then reconnect everything and see if the idle is stable with the AC on...

if that doesn't work, unplug the stock O2 sensor and see if that stops it, if so.. your stock O2 is dead

[shubby0901]

perhaps your idle valve is set too low, try this...

unplug your TPS connector

unplug your idle valve connector

then adjust the screw till your car is at 800rpm

then reconnect everything and see if the idle is stable with the AC on...

if that doesn't work, unplug the stock O2 sensor and see if that stops it, if so.. your stock O2 is dead

Ok I will try these methods tomorrow morning. It might be something to do with the idle valve as it was idling very high when I did the cleaning and I had to really tighten the screw. Even now, it idles at just under 1000. Not sure about how to get it lower.

Also was thinking of changing the O2 sensor but was unable to get it out so will have to go and buy a removal tool and sensor if I need to change that.....

EDIT: Spelling errors...

Edited November 25, 2014 by shubby0901

[Hadouken]

Did you damage the gasket to the iacv? Did you put gasket sealant on?

[shubby0901]

perhaps your idle valve is set too low, try this...

unplug your TPS connector

unplug your idle valve connector

then adjust the screw till your car is at 800rpm

then reconnect everything and see if the idle is stable with the AC on...

if that doesn't work, unplug the stock O2 sensor and see if that stops it, if so.. your stock O2 is dead

So just to confirm, thats the top or bottom plug on the throttle body? Also is it both plugs for the idle valve?

As for the gasket, I tried to be really careful about the gasket as many people said you can reuse it. I removed it, cleaned with with a dry cloth and reinstalled as it looked like it was in pretty good condition.

[Hadouken]

Google is your friend.

http://www.sau.com.au/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/