The Mitsubishi Pajero Owners Club®

Jonny2toes · Posted: Wed Nov 23, 2016 11:49 Post subject: Rough idle smoking when warm

Hi all just wondering if anyone can point me in the right direction. Missus drives 03 Shogun sport 2.5td but past month or so it will start fine from from cold with no noticeable smoke but after a few minutes warming up the idle will run a bit lumpy and starts to kick out white/very pale blue smoke on idle. smoke clears at 3000 revs. There is no loss of power and no loss of any oil/water. Have been told it is over fuelling but when searching this forum and google there comes up with quite a few reasons for the smoke over fuelling being one of them I don't know where to start. Belts were changed in the summer and has been running fine up untill about a month ago. Glow plugs are new and EGR is also blanked off. Read somewhere that there was a sensor on the pump that might be the problem but like i said to much info head is battered also takes longer to start when warm. Any pointers greatly appreciated Confused

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trekker · Posted: Thu Nov 24, 2016 8:07 Post subject:

I's start with cleaning the EGR valve, as these cause a variety of problems. A blanking kit is more certain.

Your 03 may require an over ride relay, so wait for advice on your particular model, I don't have experience of this later model.

Jonny2toes · Posted: Thu Nov 24, 2016 13:39 Post subject:

thanks for reply. I blanked the EGR off not long after it started smoking thinking it may be that but it doesn't seem to have had any effect on it.

Simon_W · ******* Joined: 21 May 2013 Posts: 4881 Location: Watford

It's worth ruling out air in the fuel line as a potential, and common, cause of white smoke.

Rig up a temporary supply of fuel straight into the injection pump, using some new fuel hose and and inline filter. Make sure that you use hose clamps and that they are as tight as appropriate. Any clean, dry, container will do such as a plastic milk bottle.

You could warm the engine on the existing supply, let it run lumpy, then switch off and connect up the temporary supply.

If it resolves the situation, it's then a matter of working your way through the fuel line to the tank pickup and locating the air leak using the temporary supply ever further 'upstream'.

BTW It's generally black smoke that's a symptom of over-fuelling.

Jonny2toes · Posted: Fri Nov 25, 2016 1:10 Post subject:

Thanks for advice. Will give it a try soon as I can. cheers

Jonny2toes · Posted: Wed Nov 30, 2016 9:46 Post subject:

Thanks Simon for previous advice. Tried the clear tube and separate supply of fuel but didn't have any effect on the smoking issue. What puzzles me is there is no smoke when it is first started in the morning until it starts warming up. ( not very clued up on diesels as you can probably tell ) Would there be anything to do with a cold start not working properly. what would be the best way to check the injectors would they have to be removed from the engine. Thanks

Simon_W · ******* Joined: 21 May 2013 Posts: 4881 Location: Watford

It's good that you've ruled out air as a possible cause, anyway.

The only thing that comes to mind concerning the cold start device is that (on the 2.8 at least) it incorporates a mechanism that advances the timing when the engine is cold. It also increases the idle speed. But if it only smokes/goes lumpy when the engine warms up, this is when the timing is returning to its normal setting. So could it be that the timing is out and it needs advancing a tad?

Please note that I am not familiar with the 2.5 engine, so take this into account when considering my advice.

trekker · Posted: Thu Dec 01, 2016 9:36 Post subject:

It's worth checking your timing. The symptoms sound like a misfire and not over fueling. If the belt tension is slack, the pump or valve timing sprockets can jump a tooth and upset the timing. The checking process is fairly basic, will you want to check this yourself or through a garage ?.

Jonny2toes · Posted: Thu Dec 01, 2016 13:24 Post subject:

Hi and thank you both for the advice. When researching the symptoms saw that the timing jumping a tooth was a possible cause but thought that I would try and rule out other causes before having to strip the front down again to check all the marks were aligned. Is it easier than that ?
Would be doing it myself as had to change the belts in the summer as a tensioner was making a right noise so changed the belts /tensioner and water pump, timing seemed straight forward to align back up. It was just with there being no smoke when it is first started that I thought there might be something to do with a cold start. The car is still being used ( missus uses it for work) so can't really check anything until she has a day off usually the weekend. Cheers

hutchy · Posted: Thu Dec 01, 2016 21:10 Post subject:

if you are 100% certain your bottom crank pulley lines up bang on with the timing marks on the bottom plastic timing belt cover you can remove the intercooler,and the top half of the timing cover,to check the marks,but on numerous occasions people including myself have reported the bottom crank pulley not lining up properly as they can delaminate, ie the outer part of the pulley twists on the rubber that bonds to the inner which can give a false reading,which why it,s best to use the mark on the crank sprocket which is a full front tear down,hence why i first said if you know your pulley is 100% spot on Wink

trekker · Posted: Fri Dec 02, 2016 9:05 Post subject:

Just an off chance.

When you changed the timing belts, did you by any chance first align the crank to pulley timing mark at TDC, then remove the lower timing cover and see how that compared to the crank sprocket timing mark ?

My 250 000 km crank pulley is still correctly aligned, so yours may be too.

Jonny2toes · Posted: Tue Dec 06, 2016 13:00 Post subject:

Hi well finally managed to give the timing marks a quick check but unfortunately it looks like strip down time as the marks don't line up. Sad

When the notch on the bottom pulley is lined up with the marks on the bottom belt cover the top marks are two teeth past the timing marks on the head.
I did read something while searching about the teeth having to be 2 marks past when lining up but when you put the tension on the belt they all line up. i know when the belts were tensioned the marks were checked and were aligned.
If the timing was this far out wouldn't I be able to tell though as there doesn't really seem any difference in running performance apart from the idle is a bit lumpy when warm.( don't really drive it much though it's missus's main car) She also says it seems to be using more diesel.

Thank you all again for the advice Very Happy

hutchy · Posted: Tue Dec 06, 2016 13:22 Post subject:

do not rely on the pulley mark and outer plastic casing as they can be out..use the mark on the actual crank sprocket once that is set then look at the cam and injector pump marks,this way is more accurate and less chance of any internal engine damage Wink

trekker · Posted: Tue Dec 06, 2016 16:39 Post subject:

Quote ...... "If the timing was this far out wouldn't I be able to tell though as there doesn't really seem any difference in running...."

Not in my experience. When my older 2.5 tdi jumped a couple of teeth on the IP sprocket due to a tensioner problem, the engine would not run below 1700 rpm, and was obviously difficult to start. Setting the idle screw accordingly, I drove home 2000 km over a few days with no noticeable effect on running performance. So what you describe could be timing IP related, but could also be something else, it's a case of eliminating possibilities.

My above question was to see if you had set the crank pulley timing marks and then with the lower timing cover removed had confirmed the crank sprocket timing marks were also perfectly aligned. If you didn't, then you've no choice but to remove the lower case, set the crank sprocket and adjust the cam/ IP timing if either are out.