Voltages on my vane air flow meter.

[lancerevo]

Well today I decided to check the voltages on my vane air flow meter.

Here are the numbers.

DOOR OPENING / VOLTS

FULLY CLOSED = 3.95v
1/8 = 3.07v
1/4 = 2.25v
3/8 = 1.67v
1/2 = 1.25v
5/8 = 0.96v
3/4 = 0.72v
7/8 = 0.55v
FULLY OPEN = 0.35v

Are these numbers good?

[grey]

okay the 323 manual has some voltages listed but is confusing

first, it says:
Terminal 2B input (Vc) = 7-9 volts
Terminal 2E input (Vb) = 2 volts with key ON, and 4-5 volts at idle.


otherwise it is all resistance tests.
323 mazda might be different

[lancerevo]

With my voltages are with the ignition on obviously, but I still can't understand how the flap closed, (at idle) is higher voltage. The usual air flow meters it's the other way round. Like at idle it is the lowest voltages not the highest.

[JohnGunn]

I'm not sure you are going to find satisfaction here. I have the Ford Service Manual, the Haynes Festiva Manual, and the Electrical and Vacuum Troubleshooting Manual for the fuel injected 1990 Festiva and I have yet to come across a list of voltage readings such as you have produced.

The most common approach to troubleshooting the VAF meter is to eliminate more common sources of those symptoms before suspecting the VAF and to see if anyone has reported a similar problem that was fixed by replacing it.

I think you would have gotten better response if the answers you seek were available in the more popular published sources.

In addition, I'm not too sure how significant the exact values are to the running of the engine. I know that in "closed loop mode" the computer's decisions on the amount of fuel to inject is guided solely by feedback from the oxygen sensor.

If you are having a problem that you think might be caused by your VAF you could start a thread on that and see if anyone has discovered a connection between that problem and a defective VAF.

John Gunn
Coronado, CA