DigiFant MAF Voltages

Digi-I or Digi-II, no matter, the pin outs on the MAF are the same for both except the wire color on pin 3. Pin 3 on Digi-II has a black/blue wire, Digi-I has blue/black. Pin numbers at the ECU are completely different.

Key on, engine off tests as follows;
Pin 3 is reference voltage from the ECU (V-ref), I think you should expect very close to 5.0 VDC.
Pin 4 is ground, due to it's convoluted path to ground, you may see a few milli-volts on it, no more.
Pin 1 is the intake air temp sensor (IAT), voltage will vary according to temperature, use a hair dryer, not a heat gun.
Pin 2 is the MAF potentiometer. Expect 0.1 VDC to 0.5 VDC with the flap at rest, 4.0 VDC to 4.9 VDC with the flap full open. Spend some time on this pin, watch the voltage rise and fall as the flap is opened and closed. The transition should be absolutely smooth with no spikes, glitches or drop outs.

I just took real time, live values from my '92 Digi-I.
Pin 4, 28 mVDC.
Pin 3, 4.93 VDC
Pin 1, 0.8 VDC, outside temp of MAF housing approximately 30° C.
Pin 2, 0.27 VDC at rest, 1.1 VDC at idle, approximately 850 RPM.

Write up courtesy of Ron, of www.Mk1Dubs.com

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