Air Flow Meter testing

[Marcus G]

Is ther any way to test the Air Flow Meter/Sensor on a VL Commodore?

I've just gone through the procedure of checking the idle speed and mixture, but adjusting the screw on the Air Flow Meter does not appear to have any effect on the diagnostic LEDs. I've tried the adjustment many turns either way, and still get simultaneous flashing of the Red and Green LEDs (i.e. no change to a lean or rich mixture indication).

[snake_VL]

my maintenence thread has some info on voltages and resistances of the afm if you have a multimeter to test it. also just look inside to make sure the wire hasn't broken. your base voltage should be 1.1-1.4 and mixture around 3.55V which is around 380ohms across pins 1 and 6. this should make them flash together. its all explained here:

RB30 Engine Troubleshooting/Maintenance Step by step

good luck

[Marcus G]

Hi snake,
Thanks for your reply.
I've looked at your post and have found it very helpful. I have found, however, that I was unable to get both LEDs flashing together with the AFM set to 380ohms. The best result was achieved at around 220ohms. The range of adjustment is from about 420ohms to 0ohms, which puts the 220ohms about half way.
Also, I cannot get anything near the voltage measurements you indicate.
I won't have time to do any further checking until the weekend.
Do you have any information regarding the pin-outs of the AFM? So far I have been able to determine that pin 1 (black wire) is earth, and pin 5 (orange/black wire) is 12V.
I understand that this type of sensor is a hot wire type sensor, and not the older "flapper" type, and have confirmed this by observation. I'll try to find the heater and sensor terminals over the weekend, but any other information would be helpful.
I also found this link; http://www.aecs.net/techniek2006/holdenvl.htm where there were no error codes, so I'll check with an oscilloscope as soon as I can.
Any information regarding the pin-outs of the ECU would also be helpful.
I have an Ellery service manual, but the electrical circuits are very limited.

[snake_VL]

make sure you do the voltage readings with the key on but engine off. pin 3 is the mixture voltage.

thats about as far as i got with these things. fixed my problem so i didn't need to delve any deeper. but if you can't adjust it to a decent mixture then i would say that the afm is stuffed. try the voltages again and see how you go, if they aren't even close to what they should be then its time to try another one or buy a replacement. let me know how you go