Elevated (high) idle speed

[|sAs|]

I'm out of ideas.

The car runs with an elevated idle speed of about 1400rpm's.

I've replaced the TPS and throttle body.
I've checked water and air temp sensors
The ISCV seems to be working since the idle is very stable.
I've checked for leaks with start gas.
Lambda (O2) sensor was replaced this winter as part of another problem.

What else is involved in idle speed control?

 

[BURGUNDY NICE]

Have you tried adjusting the vertical screw which sits on the throttle body. I think this is the one which adjusts the idle control or something and has control over how much oxygen is let in. I know Dave adjuste mine a while ago buts thats all the help i can give! I did try

 

[|sAs|]

Yes, I have tried that. It went from 1700 to 1400 by that, so something else must be at fault.

 

[BURGUNDY NICE]

Plennum chamber leaking gasket?

 

[|sAs|]

It seems unlikely to me. Shouldn't it have revved higher with the plus gas in that case?

 

[DaveL485]

Air leak below the throttle butterfly, or below the IACV, or the IACV is jammed open.

 

[craig21t]

Air leak below the throttle butterfly, or below the IACV, or the IACV is jammed open.

think this maybe my problem.

 

[Tony]

Craig are you talking about your arse again? lol.

 

[B.roadbandit]

Mine was doing that as well , it turned out to be a small split in the dump valve diaphram

 

[|sAs|]

Mine was doing that as well , it turned out to be a small split in the dump valve diaphram

I've had bad DV before, I'll plug that vacuum hose and try.. otherwise I'll have to get the IACV off and see what it does..

Does anyone know how much current the IACV draws? Can I use a computer PSU to test it?

 

[|sAs|]

Air leak below the throttle butterfly, or below the IACV, or the IACV is jammed open.

Sprayed all of those areas with plus gas with no difference. I did try the vacuum hose between manifold and DV today, and there was good suction and no change in rpm. Guess I'll have to take the IACV out and have a look at it..

 

[-Jo-]

silly question, isnt you're trottle cable a bit tight ?

 

[|sAs|]

No, the throttle cable has more to, I've actually set it a bit loose so the pedal sits a little bit lower and more comfortable on long trips..

 

[DaveL485]

Block off the pipe to the IACV. Will it still run?

 

[|sAs|]

I'll try that tomorrow.. That's the pickup off the intake elbow right? Right above the throttle butterfly?

 

[|sAs|]

Block off the pipe to the IACV. Will it still run?

I tried that today, it dies as soon as I block it off..
I also tried blocking off the PCV valve and it went down to around 1100rpm's..
What is the intended locking direction of the PCV valve?
http://en.wikipedia.org/wiki/PCV_valve#PCV_valve

 

[DaveL485]

If it dies when that is blocked off it suggests the IACV is at fault.

 

[|sAs|]

Is it possible to remove the IACV without taking down the entire front of the car?
When I have removed it, how do I go about and fix the problem?
I think it is the stepper type on this car.

Edit: I've now taken the IACV off. The hose from the IACV to manifold has cracks in it, so ideally it would be replaced, but I can't see that happening from above without taking the inlet manifold off..

Now that I got the IACV in the apartment, what do I do?

 

[|sAs|]

I removed it and taken it apart this far.

I've noticed I can blow air through it from inlet to motorjoint when the motor is not attached. with motor attached I can blow quite a lot of air through.

Is it supposed to be fully open with no voltage or fully closed?

 

[danb]

it should be fully open upon cranking which is why the engine revs up upon ignition and then starts working to stablise idle.

or atleast this my take on it LOL