please help!

[Falcman007]

Hi guys.

I'm at my wits end with trying to solve an issue with my pajero.

Its a 92 NH 3.0 V6 12v

For the last month its been revving its guts out at 2000-2500 rpm when its cold and settles down the warmer it gets to normal when the temp is normal.

I've tried another ECU, TPS, Idle control valve, temp sensor and air flow sensor.
I've checked for vacume leaks also.
I also checked the ICV is getting power and it is, Ive checked the continuality of wires going from the ECU to the ICV and all checks out ok.
All i can think of is manifold or plenium chamber gaskets.
It all started after i washed it and changed the rocker cover gaskets and plenium gasket.

I'm near ready to burn it.

Cheers, Kim.

[Drewan]

Feel your pain went through absolute hell with mine, but won in the end . check the plug on the airflow senser and temp I had corrosion on both connectors that helped with the revs, also crawl under and pull your oxy sensor soak it I'm petrol and give it a dam good thrashing with a wire brush . Perseverance will pay off in the end

[zoom]

idle speed control valve

[Drewan]

Poor bugger changed that my money is on a connection mind you this is the exact reason I picked up my NK with all the good bits for $300 and with the help of this forum its now a bloody wicked little bus

[TomW]

you can check for leaks using some starter spray (small amount) around the plenum gasket. if there is a vacuum leak the motor should rev up. When you replaced the IAC did you replace the entire assembly or just the little motor? Sometimes the wax inside the IAC valve assembly fails (not sure how?) and causes unusual behavior.

[Allan2]

I'm watching this with interest.

[Falcman007]

Feel your pain went through absolute hell with mine, but won in the end . check the plug on the airflow senser and temp I had corrosion on both connectors that helped with the revs, also crawl under and pull your oxy sensor soak it I'm petrol and give it a dam good thrashing with a wire brush . Perseverance will pay off in the end

Checked the plug mate. Looks clean but i have not tested it.
Would the oxy sensor cause this do you think?
I had the thottle body off, cleaned and out put another TPS on it now it revs to 1500 when warm! I'm sure there is a relearn procedure but I cant find anything.
Thanks mate

[Falcman007]

you can check for leaks using some starter spray (small amount) around the plenum gasket. if there is a vacuum leak the motor should rev up. When you replaced the IAC did you replace the entire assembly or just the little motor? Sometimes the wax inside the IAC valve assembly fails (not sure how?) and causes unusual behavior.

Whole assembly mate. 4 units to be exact. Yesterday I traveled 78km for another one from a pajero in a swampy paddock , got home put it on and the same thing...

[Falcman007]

Poor bugger changed that my money is on a connection mind you this is the exact reason I picked up my NK with all the good bits for $300 and with the help of this forum its now a bloody wicked little bus

Well when i washed the engine i drenched it so a connection seems the case but can i find it? Not yet. The mrs wants me to give up. Nope...lol

[Drewan]

The Re learn is as far as I know take off neg battery lead and leave door open until light goes out then put the lead back on and drive ?????? Makes no sense to me either mine was doing something but it seemed to have been caused by a combination of things revs dropped a little when I wiggled the air flow plug ,little more when I played with the coolant plug and when I cleaned the oxy utterly perfict . any smoke on startup or first load up the moter on take off?

[Drewan]

One thing you have said is that it was fine until you washed it so ....um .....er ......why are you parts swapping ? When I did the connections I gave all of them a good soak with contact cleaner and let them dry,do all of them.If it was running fine before washing it will run fine again.You had a win it took me 4 days to get mine to start after I hit it with the hose

[Green turtle]

Will be your fast idle valve in the throttle body. Its controlled by a wax pellet. Age causes it to stick and allows too much air on cold starts causing the high idle. This can be adjusted by removing a welsh plug on the throttle body and screwing in a plastic screw that sits behind. Throttle body will need to be removed to do this.

[Falcman007]

Will be your fast idle valve in the throttle body. Its controlled by a wax pellet. Age causes it to stick and allows too much air on cold starts causing the high idle. This can be adjusted by removing a welsh plug on the throttle body and screwing in a plastic screw that sits behind. Throttle body will need to be removed to do this.

Are talking about the one controlled by coolant temp? sits next to the ICV
I noticed there is one screw made of plastic on top of the throttle body? Ive adjusted that and it lowered it a tad. Mind you i wound it right in!

[Falcman007]

One thing you have said is that it was fine until you washed it so ....um .....er ......why are you parts swapping ? When I did the connections I gave all of them a good soak with contact cleaner and let them dry,do all of them.If it was running fine before washing it will run fine again.You had a win it took me 4 days to get mine to start after I hit it with the hose

Parts swapping as i started it right after and thought shit, ive fried something due do shorting as i couldnt find anything else wrong.
I also changed the plenium chamber gasket as i had to replace the rocker cover gaskets.
I can't help but think its a vacume leak around that area. I sufficated the intake and it took about 10 seconds to die...

[Drewan]

Lets compare the pair I'll go smofacate mine brb