Low O2 readings in Diacom at WOT.... please help!

[Shannen Durphey]

Craig Marcho wrote:

> > Oh, and how do you know that they should be those numbers?...  There are a
> > bunch of considerations about injector sizing, and hence pulse widths.  If
> > ya hunt around the archives some you'll find a injection duration map for
> a
> > 730 ecm (v-8), and see gm is conservative on injector opening durations.
> > Grumpy
> 
> I've got an '85 L98 Vette and when it was all stock, working properly, the
> pulse widths were 10 or 11 at WOT. These are both batch fire setups, even
> though the ECM is different, so I'm guessing again that they should be
> similar in this area.
> 
> Shouldn't 'normal' WOT readings for the O2 be in the upper 800's at least?
> 
> Craig M.
> 
Ahh...  But has anybody mentioned that 85 Vettes had slightly lower
fuel pressure than later years?  GM issued a bulletin that recommended
replacing the injectors, the cold start injector, and the fuel
pressure regulator to reduce injector clogging.  The regulator that's
used is the same as 86+ models.  I think the injectors flow more fuel,
also.  That's based on experiences with installing them in other
cars...  But I don't have any numbers here to confirm that, so it's
only a rumor for now.
Shannen
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