At 06:19 PM 10/14/98 -0700, you wrote:
>Whit,
>The hi performance PCM (computer) has a new fuel map associated with it, the
>net result is that the injector pulse width is increased wherever the
>software designer
>figured he or she needed additional fuel. I really don't know where the
>transducer is but if you hook up a scan tool, one of the options that you
>can check is the
>fuel pressure. I haven't been able to find it in the engine compartment, so
>I would suspect it is somewhere near the fuel tank or incorporated in the
>fuel pump
>assembly. The Vortech supercharger kit includes an additional in-line fuel
>pump and a FMU that changes the fuel system into a semi return system and
>the FMU
>just restricts the return line to boost fuel pressure. On my truck, we check
>fuel/air ratio in the exhaust path before the Cat. (expensive equipment
>required and
>generally used in conjunction with a dyno). If you really feel that you are
>not getting enough fuel (need to verify this on a dyno), you could explore
>the avenue of
>higher fuel pressure or step up to a larger injector even yet. Remember
>though, in cruse and idle (operating temperature), the O2 sensor in
>conjunction with the
>computer is controlling your fuel/air ratio. Only at WOT do the fixed fuel
>maps come into play.
>
So there is no mapping at cruise and idle? Does the computer just add or
reduce fuel until a certain O2 level is obtained? When you say WOT, does
that mean only at full throttle as implied or does the fuel mapping really
kick in at a partial WOT. It is not that often that I floor the thing. My
biggest problem is that not much happens until I hit WOT, then it performs OK.
Whit
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