engine surges

[leigh]

I have a 92 pajero. When at idle the engine surges up and down. If I take it to around 2000 revs it also surges up and down around the 2000 revs in neutral that is. The higher in revs the same story. I am just after any advise on where to look for the problem. It also seems to be lacking in power through the gears. It just does not have the pull that it used to have.

Cheers

Leigh

[nj swb]

For the surging problem, I'd be looking at the idle stepper control motor. I don't know how that would explain general lacking in power. Perhaps Air Flow Meter problem? I wouldn't know where to start with that - buy a workshop manual?

Good luck,

Scott

[bounceferret]

I actually have the same problem. The engine surges between 700-800 rpm quite rapidly and creates the car to vibrate and shudder when I allow the car to roll forwards very very slowly (eg bumper to bumper traffic)! starting to get annoying really.

http://www.4x4wire.com/mitsubishi/tech/throttle_body/

that is meant to fix the problem, if it doesn't the other possibility is dirty injectors.

I think my problem is the ISC, time for a new one

[MITSIR]

ISC Motor Looks like the way to go.

As for Lacking power, Check for any vacum leaks at the throttle body or anywhere else at the intake system,

I would first suggest to fix one problem at a time and start off with the power surging issue by either cleaning out the ISC or purchase a new one. Clean the throttle body also with cleaner while you are fixing the ISC issue.

I have heard from a mechanic once that the 6G72 injectors has a big performance difference when cleaned out, He used to do allot of them and people have always been suprised how much better the car runs after a injector service. I'm due to having one done to mine soon as the fuel economy seems to be rising higher.

[CRH]

This could even be something as simple as a blocked fuel filter.

This is a cheap replacement and can't hurt even if it isn't the problem.

Injectors normally cause a rough idle and the stutter can't be seen on the tachometer as it happens very quickly.

[MITSIR]

Here is a Page that could help you out for your problems you are having

http://www.mitsu4wdclubqld.org/tips/tech/tech9906.htm

Hope this helps you out abit

[leigh]

Thanks for the help

Well I cleaned out the stepper motor and there was a bit or build up in there. It seems to have improved it. I will see in the next day or two whilst driving it a bit further. I had to turn down the idle speed a little after I cleaned the unit out. I hope that is a good sign.

Any way thanks for the help and we will see how it goes.

Regards

Leigh

[Raurrie]

Hi.

Am new so please be patient. Does the 92 run a 2.6L Astron motor or 3.0L Motor. I have had a Mazda B2600 which was doing the same prob (they run the same motor basically - a 2.6L Astron Motor). After much investigation I eventually found the problem to be corrosion in the CPU which I replaced (luckily had a spare) and the problem went away. The CPU unit was made by Mitsubishi. The attached web page describes the situation better.

http://www.avproecm.com/process1.htm

I am now the proud owner of an NK Pajero V6 3.0L. Could anyone advise whether this motor is suitable to convert to LPG?

[MITSIR]

Pajero NH 1992 model should have a 3.0L V6 engine

By Memory pajero finished production of the 3.0L Engines on the NJ models then started the 3.5L from NJ upwards. Pajero NK's should be 3.5L Engines. So if you have a 3.5L Engine then Yes it will be compatible for LPG.

[6G74]

I think mitsir is right, unless you have an import i think it should be of the 3.5dohc variety, provided it is a nk, and not an nj then yes, its gas compatible. If it does happen to be the last of the 3lts with the 2 valves per cylinder heads, then no, its not reccommended for gas.