szyki

Hi!
Can anyone tell, how the intake air sensor in a '83 AFC 928 engine works?

Still working on starting it for the first time in probably many years and checking all the sensors, valves, etc one by one.

I found that, the intake air sensor should have some particular resistance between terminals in its socket.

What about the way, the sensor works?
Does the air flow open it and it gives certain resistance at a certain angle?

Can anyone help with the figures for that?

Thanks in advance,

Simon.

John Speake

The usual problem is erratic voltages as the flap moves around in the airflow. Try to measure the output volts to the L-jet ECU and push the "flappy" open and closed and check the voltage changes smoothly. You just need the ignition on for that test, engine not running :-)

szyki

Thanks John,
I'll try that during next testing everything in the car session.

cheers.

John Speake

If you remove the black cover, you will see the potentiometer that moves with the flap. The track gets worn by the wiper contacts. Sometimes it is possible to reposition the wipers onto a fresh segment of the track to make an improvement.

Wisconsin Joe

^This. There's a few threads on it over in the 944 forum (early 944s used the AFM too). It's pretty simple, I did it on my 944.

And, to be a bit pedantic, it's called the "Barn Door" AFM. "Flappy" is something else.

If you search "Flappy" you will find a lot of info about the S4 intake.

If you want to find stuff about the AFM in the L-Jet, search "Barn Door."

James Bailey

Barn door swinging in the wind .....