ML 270 2003 MOT failure on emissions

[cpfbma]

Dear All,
My 163k 2003 ML has failed MOT on emissions. I was advised to use some injector cleaner and take for an Italian tune up ( hammer up and down motorway) before re test. Took it in and it is slightly better BUT still failed. limit is 0.8, it was reading 0.85/0.86 on opacity test. Would welcome any top tips or advice on how else I could improve its emission or other things to check/change. Swirl valves have been removed, I changed oil, oil filter, diesel filter and air filter within last 4k miles, and used some STP injector cleaner. Car has only failed on emissions so its worth saving i reckon. thanks in advance

 

[ChipChop]

Dear All,
My 163k 2003 ML has failed MOT on emissions. I was advised to use some injector cleaner and take for an Italian tune up ( hammer up and down motorway) before re test. Took it in and it is slightly better BUT still failed. limit is 0.8, it was reading 0.85/0.86 on opacity test. Would welcome any top tips or advice on how else I could improve its emission or other things to check/change. Swirl valves have been removed, I changed oil, oil filter, diesel filter and air filter within last 4k miles, and used some STP injector cleaner. Car has only failed on emissions so its worth saving i reckon. thanks in advance

You could remove the air filter element for the MOT test.

 

[cpfbma]

You could remove the air filter element for the MOT test.

is that something that could work ?

 

[ChipChop]

is that something that could work ?

Costs nothing to do so worth a try. More air in to prevent overfueling is the theory. All depends if the smoke out the back of your 270cdi is just soot built up during normal driving being expelled at high revs (hence why a fast drive pre test is useful to clear the pipes) or an engine issue (injectors?).

 

[cpfbma]

Costs nothing to do so worth a try. More air in to prevent overfueling is the theory. All depends if the smoke out the back of your 270cdi is just soot built up during normal driving being expelled at high revs (hence why a fast drive pre test is useful to clear the pipes) or an engine issue (injectors?).

thank you very much, as you say costs nothing to give it a try

 

[Petrol Pete]

OP , there are loads of potions and lotions and additives you can put through the engine in attempt to clean it out for the MOT . Personally I would do a little research and try a bunch of them . what have you got to lose.

The 'remove air filter ' thing worked for me many years ago on an old Citroen I had.

 

[slade1]

Italian tune up, belt it at 4000 RPM on a motorway for around 1/2 hour.
Replace the air filter with new one.

 

[cpfbma]

I am informed by those in the know, due to the car displaying an opacity limit eg - 0.8 on the door pillar, then the tester needs to test to this limit. Without this information then a limit of either 1.5 or 3 would apply based on the cars age. Previous MOT's have been completed with a limit of 1.5 -3, with previous results from the car ranging from 0.4-0.6. so it appears i have car with a worsening emission and much stricter limit being enforced. I have researched , and add STP emission test cleaner, will add in some premium diesel and try again tomorrow. will let you know. thanks again.