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more '82 A100 2.2i probs, and ColourTune. -Reply
In message <firstname.lastname@example.org> Gross Scruggs writes:
> ... and the exhaust stream presents an 'average' of the
> conditions in all the cylinders so if one has a problem then it may be oculted
> by the output of the others. Your call.
I think a serious overhaul of the injection system is called for between 120k
and 160k, depending on conditions.
Obviously, you can see _gross_ differences between cylinders by comparing plug
colours and doing compression tests - but the basic thing to do at this sort of
mileage is an injector flow test.
The microfiche for the MB engine shows the injectors removed and inserted into
five measuring cylinders held in a frame. The fuel pump is triggered via a
jumper lead. The spray patterns of the injectors and (above all) the
uniformity of volume is measured. The interesting bit is the technical
addendum to the fiche (delivered on paper) that describes doing essentially the
same test but with the air mass sensor held in an open position by a special
service tool. I'm interested in the fact that Audi issued this instruction
_later_. Did they find that the diagnostic they had suggested was inadequate
in the field, or does the change represent "high mileage" experience?
Either way - I'm sure my injectors have only been tested at _low_ air mass
sensor positions and I intend to test them in the "new" way this coming weekend.
Committee Member, UK Audi [ur-]quattro Owners Club