Re: What Air to fuel ratio should a 16v run . ?

[Mark Shaw <autox@inficad.com>]

Chris Coracini wrote:

> with your system running closed-loop, it will always be around 14.7:1,
>
> that's what the O2 sensor is supposed to do.

Correct.

We are left to make a couple of assumptions here.  1) He was testing the

mixture on the test port ahead of the catalyst.  2) The "computer" bases
its
air-fuel ratio on the CO content.

> when the full throttle switch is engaged, THEN it's supposed to get
> rich.

Only if the engine is heavily loaded.  The closed loop system will not
driftfar from stiochiometric if you are reving the engine at idle.  Also
the time
you take to reach high revs is so short that the volume of exhaust
cannot
last long enough for the tester which is usually pretty slow unless you
own some $10000+ high-tech FDIR unit.  Most garages don't have
these (or need them).


> and you can't blow up your engine from being too rich, only bog it
> down.
> too lean is much worse.

Too rich may not destroy the engine, but it is hell on the catalyst
which
can overheat badly and either melt/flame something or degrade quickly.
One failure mode is to melt the honeycomb core which will partially
block the exhaust flow ALL the time causing power loss.

Mark


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