I'm no expert, but I had a similar problem when I replaced the ECU on my
'88 with a new/rebuilt unit.
An addition clue appeared when I tried to get the van smog checked and
it just barely squeaked by on the CO level.
Black on the tailpipe makes me think it is running rich.

I have not tried it yet, but I'm thinking that the preset spring tension
on the ECU is too loose, causing a rich condition.
I am planning to increase the tension by a couple of notches, and see if
that makes a difference.

Todd
'88 Westy

Matt Heydon wrote:

>My '87 Weekender bucked and kicked like a brahma. I finally narrowed it down to what I was hoping it wouldn't be, the ECU. After a $450 rebuild the van runs great (i'm sure also attributable to the troubleshooting i did beforehand). Before the ECU was rebuilt I got a solid 18-19 MPG. Now with the rebuilt ECU I get 14-15 MPG on the highway!!! Has anyone seen this before or have any ideas?
>
>Many thanks,
>Matt
>'87 Westy Weekender
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