Diesel Smoke Test

12 Jan 2009
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United Kingdom
Ones motorcade is due for its MOT. The old diesel always has trouble passing the smoke test and usually needs the MOT tester to give it a blast up the royal mile and back before the old girl will play ball. Would removing the air filter prior to the test have any effect as it used to on the emissions test for petrol engined cars?

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Get Carmilla to take it to the garage for you, if she flutters her eyelashes and shows a bit of thigh, ones MOT problem should be resolved. :LOL: ;)
Buy some diesel improver by Forte if you can get it, and give the old girl a jolly dose....you can actually see the emissions coming down once it runs through. Millers Dieselclean is another good one. Cheers John
Heartfelt thanks for your replies. It is gratifying to know that one can count on ones subjects to assist one in their time of need. I have half a bottle ( or was it a magnum... ) of injector cleaner in the garage and will instruct its addition to the fuel reservoir forthwith.

I would however like to refer back to my original enquiry as to whether the removal of the air filter would have any effect on the smoke test?

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Sir, removal of the air filter will only improve the emissions if it's choked and it's replacement is overdue. If the air filter is healthy it's removal will make no difference.
Your faithful subject,
give it a ferrari tune up,i:e a long blast up the nearst duel carrigeway.
as an mot tester and having tested many diesels both old and newish I have always found that the best way to get them through a smoke test if they fail is to change the engine oil and filter.If you can stretch too it add a cleaner to the oil run engine for 15 mins and then drain old oil. remember the oil acts as a filter and impacts the emissions!
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