A MAF sensor works by sensing how much a heated resistor cools. The
more
it cools, the higher the airflow. Since you know the cross section of the
MAF sensor, you can figure out the volume of air coming into the engine.
However, if the air is tumbling around inside the MAF sensor and not
flowing straight through it, you will get an inaccurate reading, since the
air may be moving very slowly over the sensor but moving quickly on the
edge, or vice versa.
I don't know about Nissans in particular. However I know that GM cars
all
have a thick "screen" in front of the MAF for precisely the purpose of
making the flow laminar. If this screen is damaged I have seen really
weird MAF values before... So your air filter could be causing tubulent
air flow, messing up the MAF reading. The screen kind of looks like a
thick honeycomb. I don't know if anyone makes an aftermarket one to
install but it might be worth looking into...
-Matt
> My STS SE-R has a strange problem where the MAF voltage gets erradic
>between 2000 and 3000 RPM when part throttle. If I remove the K&N filter on
>the end of the Cold Air Intake, the problem goes away. I assume that the
>filter must be causing turbulent air flow past the MAF during that
>particular RPM range. It has had this problem ever since I put the Cold Air
>Intake on. When I call up several shops to try and find a different filter
>to use, everyone is telling me I'm nuts and that the filter can't cause
>this?
> So the question is "am i nuts" ?
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