wiered Idle problem

[GIGOLO]

Hey everyone,

My car just started this weird idle problem where it hunts up to 1.5krpm then drops back to 1krpm and so on, normal driving is fine just when I stop at the lights etc. it idles really bad.

The car was driving fine Saturday night but when I started it Sunday, after the cold start came off it did this weird hunting thing.

When the AC kicks it the idle stabilises at around 1krpm, but when it goes off it starts hunting again.

I have tried:

-adjusting the idle screw

-tightening the BOV (GFB hybrid)

-checking all hoses to make sure they are connected.

I have a PFC, could some setting on this be the problem, although it has been working fine previously.

It has done this once before on a skid pan, but all I did was turn the car off and on and it fixed itself?

I am quickly approaching the zone of confusion.......................

[strutto]

What car mate?

[GIGOLO]

1996 series 2 gts-t with the RB25DET

[youngcodger]

If you've got an R33 especially, it's your charcoal filter. This is a very common problem and you don't have to worry about it much. Depending on the conditions it'll have its goood days and bad days. If you really wwant to reposition your charcoal filter, you'll have to use up a fair bit of money.

[GIGOLO]

Were is the charcoal filter? and what does it do?

[youngcodger]

The charcoal filter is a filter for the air conditioning. It just simply filters the air so it is pure. However, it can end up slightly changing the idling of the car. It's nothing to worry about. I have the same problem on my R33, but it's severity varies.

[superspit]

make sure your dipstick is in properley, and inspect your oil filler cap seal!!! (just check them, it can't hurt!!) Mine (R33) stalls when I remove either one of the 2 when warmed up and idling.

[GIGOLO]

can anything be done about it, aside from relocating it?

[INASNT]

The charcoal filter is a filter for the air conditioning. It just simply filters the air so it is pure. However, it can end up slightly changing the idling of the car. It's nothing to worry about. I have the same problem on my R33, but it's severity varies.

Are you sure about this?

As i thought the charcoal filter is used to filter out petrol vapour from the fuel line. As some cars with the charcoal filter removed you can smell petrol vapout in the car when at the lights.

I also have a weird idle problem at the moment.

The car used to idle at around 1300rpm when i was coming slowing down to stop and then go down to 900 when the car was stopped. Now it idles 1300rpm all the time when warm and around 1700rpm when cold, which wastes a shiload of petrol.

I have a pfc and the idels are set at 950rpm and 1200rpm or so for cold start.

Where is the idel control screw in the engine bay and is this meant to over ride the pfc settings?

[95GTST]

Gigolo, I had similar idle problems awhile back, not sure if it's the same thing, but the problem was carbon/crap build-up on the idle-control valve... Had this cleaned and haven't had a problem since, Dyson said that this was a pretty common thing with imported jap cars.

[INASNT]

where is the idel control valve located?

[WazR32GTSt]

where is the idel control valve located?

if its the same as an rb20 then its on the plenum near runner for cly #6 (called 'aac valve')

small square thing with a cylindrical thing attached. There should be a maroon plug going into it

remove the maroon plug

unscrew / tighten screw

replace maroon plug

idle changed!

just for the record (not sure if htis will help at all...):

i had htis issue where one day my car just started jumping idle from 500rpm to 2000rpm then stalled. Happened about 2 or 3 times on the same day.

When i got home, i got out the trusty old 'brake caliper cleaner' and cleaned the afm, took off the aac and gave it a clean, took off the O2 sensor and gave that a spray to remove any deposits on the probe, and reset the ECU

have never seen the weird idle problem again...

Cheers,

Waz.

[GIGOLO]

Approximately the same on the R33, but I had no maroon plug.

"Brake Caliper Cleaner" seems a bit harsh to me, I'll give it a go with some carby cleaner

[b1lly]

I think not .. as the guy below said, its for the vapour in the lines ..

which usually also reconnects to the intake so that the captured vapour can be sucked in by the engine again.

The charcoal filter is a filter for the air conditioning. It just simply filters the air so it is pure. However, it can end up slightly changing the idling of the car. It's nothing to worry about. I have the same problem on my R33, but it's severity varies.

<{POST_SNAPBACK}>

[Ant97GTR]

I had the same problem in my R33.....

One of the small vacuum hoses had come off the little valve thing right next to the screw to let air out of the cooling system, towards the front of the engine above the fuel rail. Popped it back on, attached a clamp and the problem never came back.

Hope this helps....

[BH_SLO32]

Possible problems:

1. Air leak. Pinch the blow-by hose (the one connected to the intake plenum) and if the engine revs increase you probably have an air leak.

2. O2 sensor. At idle disconnect the O2 sensor and see if the hunting stops.

3. Plugs. Check condition.

Hope this helps.

Cheers

[gtst1976]

Another cause of Idle Hunt problem can also be the air flow meter, try cleaning it with contact cleaner. Sometimes they get contaminated and cause the car 2 run little rich only on idle.

Just a thought....

[blackr32GTS]

I have the same problem with my R32. I was stuffing around with air hoses on the weekend and now the revs bounce between 800 and 2000 when idling. Doubt it would be the charcoal canister as this only filters petrol vapours from the air. Guess I'll check air hoses around the plennum chamber.

[chippa33]

could someone tell me why my 93 r33 would idle normal sittins still and idle at about 1100 to 1400 rpms whilst car is moving but not in gear

Edited August 24, 2005 by chippa33

[WazR32GTSt]

could someone tell me why my 93 r33 would idle normal sittins still and idle high whilst car is moving but not in gear

<{POST_SNAPBACK}>

define "idle high"

like 2000rpm? 3000rpm?

or just above 1000prm?