Pajero Owners Club of South Africa

Hi Guys

I am having something funny with my idling when I put the aircon on. According to the service manual, the rpms under low load and high load with A/C on should be 800 and 1000rpm. I am driving a gen 3 3.2 DiD Manual transmission.

If car is running with a/c on (stationary or moving). The idling alternates between around 850 and 1100 rpm every couple of minutes. It does this when engine cool or hot. Its a bit disconcerting in traffic when idling along on gears and suddenly car jumps forward at faster speed. Not a massive speed increase but gives me a fright every time and my reflexes cause me to brake hard un-necessarily. My thoughts are that the load doesn't change so rpms shouldn't change either. I also think that should the load change, the revs should gradually change so there isn't the jerk. I have never experienced this on another car's a/c so i don't think it is normal. Idles perfectly when a/c is off.

After looking on the forum, I came across these two threads with regards to uneven idling:
https://www.pajeroclub.co.za/forum/view ... =52&t=4274
https://www.pajeroclub.co.za/forum/view ... =24&t=3035

They are not the same issue, but I am wondering if my butterfly valve could be the problem and needs to be adjusted.

I told dealer about the issue on last service and they said they cleaned sensor contacts. Issue persisted unchanged. I always take what work they say they have done with a pinch of salt so could be that no sensor was checked. I don't want to fiddle with butterfly valve un-necessarily as cars runs perfect without a/c on. My thoughts are that my problem is a faulty sensor or dirty connector pin.

Any suggestions on where to start fiddling?

Much Appreciated

James

It seems its not only when A/C on, The engine also alternates when A/C off, butt not as often and not as drastic and so I never really noticed it.

If I adjust the butterfly valve, are there any negative affects if I do it wrong or if the problem is elswhere?

James

Hi James
I also had idling issues similar to what you describe. Mine has been going for a long time and I have over 300 000km.
Recently I cleaned the butterfly unit by removing it and using carb cleaner. This did not change much, so I adjusted the hot idling using a 7mm spanner and a Philips screwdriver. This can be dome very easily and can also be undone very easily if you are not happy.
I loosened the locking nut and turned the hot idling screw in by a quarter of a turn. Holding it with the screwdriver, I then tightened the locking nut.
My first try was a small improvement. The second time I turned the screw in by 1/8 of a turn.
The revs seem more stable while idling and definitely with the aircon on. In traffic, it would feel as if it was idling to low and wanted to choke off.
I am happy with the change I have made, and there is no noticeable change in fuel consumption.

Thanks Bernard!

Will give it a try on the weekend and see what happens.