MAF (Mass Air Flow Sensor)

      The Mass AirFlow meter is designed to measure the amount of air coming into the engine. Your computer knows that X voltage out of the MAF means Z amount of air and adjusts itself accordingly. The critical part is the relationship between X and Z. The percentage is what matters. When you add more Z without increasing X (by putting your sensor in a bigger body), you completely screw up the relationship between the two. The most interesting part is that This relationship is not necessarily linear. This is where it gets really hairy (not literally of course). If you add Z without increasing X, you get a lean condition due to the extra without added fuel. If you increase X without Z, you get the opposite.
      There are lots of companies out there who claim that their meter is "calibrated" for a certain injector size. This is basically horse hockey. What they've really done is use a sensor that fools the computer into using less fuel than it normally would because the injectors flow more on their own. The ONLY way to properly change your MAF or your injectors is to have a computer that's calibrated for the output of your new meter and/or the output of your injectors.

How do you know if you MAF is working correctly?

The voltage at terminals A and B with engine on should be 10.5V
The voltage between C and D should be .34 - 1.96 V at idle.
If not you may have an electrical prob in the sensor head.

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