Has now passed all the MOT tests, bar the 'Natural Idle Test'
CO level at 2000 revs is a Pass, and Lamda is also a Pass. The last item on
the test sheet is simply CO Level 0.85 %, which is also a Fail. I assume
this just refers to the Natural Idle Test.
Failed on the same points the first time, so on the advice of the tester and
the garage that did the work on the brakes etc, I bought 1 new Lamda sensor
which the garage fitted today. It made no difference, so the 2nd sensor was
changed for the one that had been removed, on the basis that if it wasn't
any different to the new one, it might be the 2nd sensor that was faulty.
Still no difference. It would appear that both Lamdas are OK. but CO levels
are still too high a tickover
I'm going to have a diagnostic check done by my local BMW dealer, who
hopefully will be able to pinpoint the fault, but in the meantime has anyone
any suggestions of what might be causing the high CO reading at tickover?
Get your local dealer to check the fault memory. Alternatively, how far do
you live from your MOT station? Are you close?
I have had vehicles fail the MOT on emissions tests, but the next time I
look it there (without changing anything) it passed! I didn't change
anything, I just got it hot first by a decent run, and it passed! In the
trade, it's referred to an Italian de-coke! But obviously observe the speed
Was it fully warmed up? Does the test report give the oil temperature?
I've only attended one test on mine at a station some 3 miles away, and
they spent ages warming the engine at fast idle before they'd even conduct
*Sleep with a photographer and watch things develop
Dave Plowman email@example.com London SW
The garage that did the brakes etc, took it for the MOT which was about 3
miles away, so it should have been reasonably warm when it got there.
But the notes on the test sheet say:-
'Engine speed measurement by-passed'
'Engine oil temperature by-passed - Cooling fan cut-in'
I would assume if the cooling fan cut in that the engine was fully up to
temperature, but you have a point. I'll see what the local BMW dealer wants
for a full diagnostic check, and if it's pricey, it might be worth booking
another test, then thrashing it for a few miles immediately before it's
tested. Give it an Italian tuneup as they say. :-)
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