Project84

Does the AFM signal the fuel pump to shut off if the AFM does not sense air flow? My car (86 GXL) starts, idles and dies. If I rev the gas, the RPMs don't go up. I changed the ECU, the TPS is new and is set correctly, and I am thinking about trying the AFM next (yes, its plugged in). I had my friend hold the flapper door all the way open while I floor the pedal and tried to start it. It doesn't respond to the throttle position nor the AFM. Tell me all you know about the AFM and how it works so I can better trouble shoot. The FSM tells how to check the ohms thoughout the AFM, but I heard that this wasn't really a reliable check.

Any info will help.

Evil Aviator

See FSM pg 4A-54, #4, note the part about "Measure the resistance between E1 and Fc (fuel pump switch)..."

See FSM pg. 50-31 for a larger diagram.

Note that there is a parts index on FSM pg 50-11 that will help you find where certain components are located in their associated electrical systems. Also note that the last few wiring diagrams in the manual are very handy for finding components on the car by following the appropriate harness.

Project84

I tried that E1-Fc. It says I should get 0 ohms at full open. I get a little over 1 ohms at full open. I heard that the check isn't that reliable. I did notice something. On the wire harness that plugs into the AFM, there is one less wire on the harness. If you look at the diagram you gave me, look at the plug that says E2. On my wire harness, there isn't a pin to match up with that plug. Its just a blank hole. Its that normal?

Evil Aviator

Well, I threw out my AFM a while ago, so I can't exactly take a look, lol. However, looking at the wiring diagram, there are two E2 pins, and they look like they have the same routing, so it is possible that only one is installed, but I don't know for sure. Maybe somebody with an AFM can take a look?

Based on the diagram, E1-Fc is just an on/off switch, so I don't think that a little resistance is a problem. I think the main issue is that there is no continuity when the AFM door is closed, and there is continuity when it is open.

Project84

Thats what I have. No continuity when its closed, and continuity when its open.