'89 740 belching black smoke

I have a 740 (non-turbo) with ~143k on the odometer. It runs really nice,
but is exhausting this smoke. It is barely perceptable at idle and just
driving easily down the road. When it is accellerated hard it is very
obvious. In the old days I would be looking for choke settings/adjustments.
Now with everything fuel injected and computer controlled I am thinking
sensors or ECM related. Can anybody help me diagnose this problem. It has
stumped my local mechanics (admittedly not Volvo experts) to date.

Thanks in advance,

Kirk

 

Generally black smoke like this on a non turbo is caused by a bad air
mass meter. Unfortunately there's no easy way to test except
substitution.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

I should have mentioned that this was done already. I might revisit the
issue though since it was a part from the scrap yard.

Thanks,
Kirk