How do you test your mafs with a multimeter?

[TomGreen]

How do you test your mafs with a multimeter?

I have a 240sx which I think the mafs is bad, Do you check voltage or ohms?which posts? on the conector are checked?

[Rev_D21]

Ok there should be an orange wire on the MAF itself. Connect the (+) of you multimeter to it(backprobe the connector...paperclips or sewing t-pins work best) and place the (-) on the meter to ground. With the ignition on(enging stopped) you should have 1.0volts (I am going by the altima manual right now so it may be different). Idle(engine at normal operating temp) you should have 1.0-1.7 volts. Idle to 4,000 RPMs you should have a linear increase from 1.0-1.7 to 4.0 volts.

[Q45tech]

The curve of the voltage increase is not linear!... with air flow in grams per second. A complex exponential equation is used by ecu to translate the voltage into flow. But at max rpm and max flow {grams per second} the reading should be 4-4.4 volts [this 0.4 VDC range represents a more than doubling of the flow at the top.

Very linear at low-medium flow rates [1.0-1.8 VDC] is a HALLMARK of Nissan MAF.

Note: CFM is a variable and inaccurate definition as the mass changes 1% per 11F and the humidity and barometric pressure affect the AMOUNT of oxygen in a cubic foot of air.

CFM at SAE STANDARD temp, pressure, humidity is correctable but grams per second is always grams per second.

[Rev_D21]

Sorry, as I said I was going by the Altima FSM which is the only source I have in the house at the moment and it says "check for linear voltage rise in response to increases to about 4000rpms in engine speed." <thats a direct quote for the altima KA24DE ODBII system.

[Q45tech]

Bad translation from Japanese, they mean progressive increase.

[Rev_D21]

You are correct