[Gmecm] 1990 Cavalier 3.1l running very rich, ECM?

[Jay Maechtlen]

>          Here's the thing, it's got the "wrong" ECM.  It's a 1990 3.1l 5spd
> Cavalier, and it has a 1989 2.8l 5spd Cavalier ECM.  Could this be the
> problem?  Shouldn't it run pretty well, maybe a bit lean at WOT (which we
> haven't even attempted)?  I have had a lot of success running my 3.4l MGA
> conversion with several different stock 3.1l ECMs, including passing
> emissions with flying colours.  I expected this car to run pretty well.
> Would it likely run better with a 3.1l auto ECM??

maybe dumb question, but:
do the two engines use the same injectors?

If this motor has bigger injectors than the ecu expects, it might not be 
able to adjust enough?

>
>          This is not actually my student, but I am supposed to know a bit
> more about these GM systems (ha ha!), so I've agreed to help this kid -he's
> a go getter, and that's rare amongst the teens we see in shop today...
>
>          I admit we don't know if it ran before being donated to the shop
> with stripped spark plug holes and sand in the intake and heads (!), but it
> runs well now, except for the fueling issues.  So, any suggestions? Thanks a
> bunch for any ideas!!
>
>
>
>
>
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