The Mitsubishi Pajero Owners Club®

jonee34 · Posted: Thu Sep 30, 2021 15:20 Post subject: Idle speed from cold

Hi guys, i have had a good look around here but my issue seems to be a rare one. I have just purchased a 2005 shogun 3.2 diesel , my issue with her is that on initial start up from cold, the idle speed shoots up to just under 3000 rpm for about a minute and then drops to about 2100rpm for another minute and then settles at 1100rpm from then on. I have access to snap-on code readers that have only brought up one code which was 16, this sensor seems to have been replaced. Everything else seems to be ok, ive found no air leaks or fluid leaks. Any help would be much appreciated.

Many thanks

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assassin · Posted: Sun Oct 03, 2021 2:01 Post subject:

Possibly the throttle potentiometer behind the throttle pedal, this has thre main settings and the first position is idle where it sets it to the idle map and the vehicle idles, second stage is the throttle position which is a variable resistor and as you press your throttle it alters the resistance to give the required throttle, thirdly the next position is full throttle and this just alters everything to give the vehicle full power, ensure the TPS moves to the idle position by first checking the throttle pedal is returning to activate the idle map, it could be something as simple as a sticky throttle pedal not returning to the idle position due to dirt, rust, or worn bushes.

Next check the throttle potentiometer itself and ensure it is connected to the pedal and is activating the idle map.

RahA795 · Posted: Tue Oct 26, 2021 10:32 Post subject: RE:

jonee34 · Posted: Fri Oct 29, 2021 15:32 Post subject:

Thank you guys for the replies. I have got the pedal completely off now and my car has had some sort of pedal position modification. seemingly to move the pedal into a higher position. i have got another pedal switch and will be following the idle speed relearning process, i will let you know how it goes. many thanks

jonee34 · Posted: Sun Oct 31, 2021 9:45 Post subject:

Well the second hand pedal was installed with no issues except my shogun would not start unless a third of pedal travel was applied to the throttle. No idle at all. carried out the idle speed learning procedure several time but to no avail. So i put the old modified pedal back on the car and the idle speed at warm is now 1200 rpm. The modification to the old pedal assembly was a piece of rod welded under the pedal so as to restrict its full return. The car is now undrivable as when its cold it sits at 3500 rpm and its got 180K miles on her and at that revs i believe engine failure is a risk. Any help would be much appreciated.

Many thanks

assassin · Posted: Wed Nov 03, 2021 5:02 Post subject:

Back to the beginning:

When the vehicle was working did you engage neutral and aooly the handbrake when stationary such as at traffic lights? if so did the engine idle around 760-780 RPM for a couple of seconds then drop to 750RPM and the tacho needle flick slightly? if so this is working correctly and the most noticable thing would be a slight change in the engine note

Your throttle potentiometer works by having three positions, with the throttle released it has either a tiny microswitch OR a piece of copper strip which the throttle wiper sits on, this is the idle position and it engages one of the three engine maps, the idling map, as soon as you move your throttle by pushing the accelerator the wiper moves from the engine idle map position and onto a variable resistance track, this is the engine running track and as the wiper moves over this section the resistacne alters and the resistance dictates the throttle position and the load applied to the engine, this has a variable resistance depending upon the throttle position. At the top of your throttle potentiometer you have either another microswitch OR small copper strip the wiper runs onto, this engages the full throttle map and all hell breaks loose, everything in the engine alters to give the vehicle full throttle and it pulls like a train.

If the throttle pedal has been restricted it isn't fully closing and engaging the engine idle map, it is then relying on the running map for idling and they only idle down to 760-780RPM on the engine running map, hence the slight delay when the vehicle switches betweeen the running and idle map and when accelerating from idle to the running map.