high idle

REDAUXR6II · 03-09-2009, 06:41 PM

Hey All,

I am having a problem with my XR6, at idle it is sitting at 2000rpm.

would a stuck ISC cause this?

Cheers

JMO · 04-09-2009, 07:11 PM

Possibly, but I doubt it. I'd be looking for a vacuum leak or at the throttle position sensor.

Stattic · 05-09-2009, 11:49 AM

wow i thought my 950rpm was high lol thats crazy

JC · 05-09-2009, 01:59 PM

Quote:

Originally Posted by REDAUXR6II

Hey All,

I am having a problem with my XR6, at idle it is sitting at 2000rpm.

would a stuck ISC cause this?

Cheers

Yes, it can. This happened on my EL (not much difference between EL and AU ISCs). A new ISC fixed it. If the ISC keeps the revs low, cleaning can help, but if it's keeping the revs high, only a new one will fix it, from my experience.

Mr_4.0 · 06-09-2009, 01:38 PM

Quote:

Originally Posted by Stattic

wow i thought my 950rpm was high lol thats crazy

why is your idle so high?

i have a wade 1521a cam, and my idle is smack on 750rpm. no hunting. its all in the tune.

REDAUXR6II · 12-09-2009, 01:19 PM

tried cleaning it but not luck a new one is on its way, ill post up what i get after it goes onto the car

POELWYK · 12-09-2009, 02:28 PM

lol mine sits around 1,000RPM and mines a stocker besides the Air intake

Stattic · 12-09-2009, 11:09 PM

Quote:

Originally Posted by Mr_4.0

why is your idle so high?

i have a wade 1521a cam, and my idle is smack on 750rpm. no hunting. its all in the tune.

wish i could tell you lol
cant afford to get it retuned... and its strange cuz when i first got there it was sitting at like 750-800 perfectly and then after a while it just started stalling so they gradually upped it

REDAUXR6II · 22-09-2009, 12:37 PM

well i have replaced the IAC but no luck, the car still idles at 2000 rpm, i have tried unplugging the IAC and starting the car and it idles perfectly.

but as soon as the IAC is plugged in the car will not idle below 2000rpm.

Any ideas people?

REDAUXR6II · 22-09-2009, 01:28 PM

i have checked for vacuum leaks and cannot hear any evidence of this. i pulled the TPS off and found that it has gone very sloppy inside, so looks like that is the culprit.

I will let you know once i have replaced the TPS.

Cheers

REDAUXR6II · 23-09-2009, 11:21 AM

ok well the TPS seems to have resolved the problem, the car still idles a bit high but then pulls down to 800rpm.

i am resetting the ECU make the car relearn its settings

cheers

REDAUXR6II · 23-09-2009, 01:57 PM

Well it appears that i spoke too soon.

The car is still idling at 2000 rpm.

I have done some testing and found the following:

When the car first starts idle is at 900rpm roughly
When you touch the accelerator it idles up to 2000rpm and will not move.
If you disconnect the IAC and start the car it idles at 900rpm, if you touch the accelerator it revs up then comes back down to about 1500rpm then settles down to 900 again.

I have replaced the IAC and TPS but the problem is still happening.

Any ideas on this? it is becomming very bloody annoying.

I have tried disconnecting the battery (positive) terminal for 1 hour to reset the computer but the problem still occurs.

JMO · 23-09-2009, 02:06 PM

Is the butterfly (circular bit inside) in the throttle body becoming stuck open perhaps?

REDAUXR6II · 23-09-2009, 02:08 PM

Nah i checked that the butterfly is completely closed its almost like the IAC is sticking open, i have tried 2 different IAC units but the problem is the same.

REDAUXR6II · 23-09-2009, 03:14 PM

i have done yet more testing and found a loud hissing noise (like rushing air) which i narrowed down to the gasket near the inlet to cylinder 1, I did the trick with the hose and my ear.

how hard is it to change the intake manifold gasket?

Cheers

REDAUXR6II · 23-09-2009, 04:22 PM

Ok i have found the hole in the gasket, its about 1cm long, a new gasket is on its way.

Is there anything i need to know about changing the gasket? such as the order to tighten up the bolts or if they require specific torque settings?

A question about this, since the air is rushing into the manifold would this cause the MAP to give incorrent air flow readings and tell the ECU that based on the air flow in the intake manifold that the throttle is open and to provide fuel based on this?

just curious thats all

TE029 · 23-09-2009, 09:18 PM

Quote:

Originally Posted by REDAUXR6II

Ok i have found the hole in the gasket, its about 1cm long, a new gasket is on its way.

Is there anything i need to know about changing the gasket? such as the order to tighten up the bolts or if they require specific torque settings?

A question about this, since the air is rushing into the manifold would this cause the MAP to give incorrent air flow readings and tell the ECU that based on the air flow in the intake manifold that the throttle is open and to provide fuel based on this?

just curious thats all

Hey mate,

As far as the torque setting goes for bolt tension there is one that comes in the packaging of a aftermarket gasket but not the factory genuine ones IIRC but that said providing you dont swing on them with 1/2 inch drive gear, use 3/8 drive and go as tight as possible.

From experience get a gasket (the metal one) for where the coolant housing mates up to the head at the front, they tend to leak once you remove and replace them. Cheap insurance and lets you access some of the bolts more easily if you remove it.

The job is not too hard but allow yourself plenty of time (took me about 2 -3 hours i think.) and plenty of patience.

The air that gets sucked in is unmetered air and leans the idle out and normally causes it to surge at idle rather than run smooth,
My idle speed was still fine so hope this fixes yours but that said if it is blown needs doing anyway hey.

Cheers
Mick

REDAUXR6II · 23-09-2009, 09:43 PM

Thanks for the info, ill grab that gasket as well, yeah hopefully it helps the situation, if its still idling at 2000 rpm after the change i will probably have to take it to someone.

REDAUXR6II · 23-09-2009, 10:18 PM

i suppose you could describe it as a surging, when the car starts its idle sits around 900 to 1000 rpm, then if you accelerate past 2000rpm the car will slow down to 2000rpm then sit there until you turn it off and start again.

i noticed that if i put my finger over the hole the idle changes slightly so i am pretty sure that this should fix things.

REDAUXR6II · 25-09-2009, 04:16 PM

Hey All,

Well new gasket is in a all problems are solved, since replacing the IAC, TPS and intake gasket i have resolved the following:

car not not starting on first try
car missing at idle
pinging

TE029 · 25-09-2009, 08:34 PM

Good work mate glad to hear the gasket fixed it,
Mick

REDAUXR6II · 25-09-2009, 08:39 PM

Again Thanks all for the private messages and help