The Mitsubishi Pajero Owners Club®

[AlBez]

Hi all

I have a 2012 MK4. It’s really starting to get on my tits.

Runs fine starts fine. But now and again, when accelerating from a standstill it will run lumpy. It crawls along at 1mph then all of a sudden will kick in and run normal again. When it’s having it’s “moment” if I click it in neutral and give it a rev it splutters and sounds like it misfires but as soon as the problem comes it’s gone again. Even if I plant my foot on the floor it just crawls along then all of a sudden sets off like the clappers. It will then run normal for anything up to a week then do it again.

There are no error codes stored and no lights on the dash.

Since the problem started I have changed garages, thinking it may be bad quality fuel. I have changed the fuel filter, had the tank off and cleaned all the fuel lines and tank out and also had a spray cleaner on the EGR to see if it was that.

My mechannic is at a loss and tells me he can’t sort it and it’s driving me nuts. Please someone tell me they have had the same issue and know exactly how to fix it.

Thanks.

[Google]

[Simon_W]

I'm not familiar with the Mk4, but to me it sounds like it could be the old diesel enemy of air getting into the fuel system.

[AlBez]

[Simon_W]

I am assuming the Mk 4 filter is the same as the Mk2 and Challenger, and that the housing looks something like this:




Firstly make sure the fuel filter is fitted properly and hasn't got the 'extra' seal. The top should look like the one on the left and not the one on the right.  



Also check that the water trap at the base of the filter is tightened up properly onto the O-ring.


I'd then start by replacing the existing sections of flexible fuel hose both into and out of the fuel filter housing with clear tubing.  For good measure you could insert a small inline filter as it's easier to see the air that way.  Something like this:





Make sure all the connections are properly tightened using fuel hose clips.

When it's all done, see if any air is in the inline filter where it will congregate if the filter lies horizontally.  If it is, then it's a matter of working back to the tank until you find the source of the air ingress. As you haven't mentioned difficulty when cold starting, if it is air in the system it's probably getting in to the filter or the hose to the pump. If it was before the filter the fuel would probably be draining back into the tank and giving starting problems.


But please note that yours is a Common Rail diesel so do not attempt to bleed air out of the high pressure system!