[mdlug-discuss] [TECH SUPPORT REQ] OBD-II typical readings

[Drew]

* Aaron Kulkis <akulkis3 at hotpop.com> wrote on 26.09.2007 21:15:39:
 
> Perhaps your Mass Air Flow sensor is reading high (engine
 
> By different means, a dirty air filter can also cause
> an overly rich mixture.

    If it's a carbeurated engine I would agree. But a computer controlled fuel injected engine is supposed to automatically adjust the fuel mix to match the air flow, whatever it may be, either by reading the mass air flow and dividing by 14.7, or else by moving it back and forth as required to have the tiniest detectable unused oxygen in the exhaust. Restricting air flow shound result in proportionately reduced fuel metering. 
 
> Fuel filter... it's amazing how a used up fuel filter can
> rob you of both mileage and power. I'm not sure if it could
> cause overly rich readings, however.
>

As Dr. Bob points out this should *reduce* fuel flow. And the adjustment process should still result in stoich mixes.

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- Drew.