I just hooked up my AFM to do this test. I plugged in the 9V, and measured the output voltage. I didn’t really try to determine the flap angle, but the voltage appeared to rise steadily from ~0.5V to ~8.0V as I opened the flap. The top/bottom range is roughly what the test chart on the 944 AFM page (http://www.iprimus.ca/~trauttf/temp/AFM/) indicates as being normal.
The only abnormal thing was when I made sudden movements on the flap, my Fluke would read OL (over limit/overload) for a moment before finding the voltage. I’m guessing this is just natural behavior since everything else seemed normal, but I don’t really have an explanation for it. Does this seem normal or should I be concerned that something isn’t working correctly?
Next step for me is testing the TPS. If I understand correctly, the continuity behavior is supposed to look like this, right?
Problem I’m trying to solve:
During my last race, the car would bog down around 4500 RPM on several of the straights. I’d have the pedal to the floor and the engine just crawled from 4500 up. It didn’t feel normal at all. I have an over-shaved head (that sounds funny) that I’m compensating with a thicker head gasket, so the net effect is I’m probably a little lower than normal on the compression – but just a general drop in power isn’t what this felt like. Normally you expect slow build up and then faster build up as the RPMs rise – this was the reverse. The engine felt like it hit around 4500 and then just decided to take a siesta. I’d exit turns faster than other people, and then get caught halfway to the next turn.
Reading this thread, it would sound like either 1) my TPS is busted, or 2) my coolant sensor is busted. Or a harness problem related to one of those.
I replaced one of the coolant sensors when I was first building the car, and I could have sworn I replaced the DME one – can someone confirm that’s the two pin one? http://www.autohausaz.com/pn/0280130026?
A third possibility I wonder about is – would a stuck closed thermostat cause a problem with the DME coolant sensor being able to read the correct temp? Another data point here is that I have the 7psi oil pressure switch swapped in as my coolant pressure switch. It took several laps before the light would go off. I haven’t really worked through what my hypothesis would be here, but wondering if it’s related. Like maybe flow is prevent the temp sensor from reading proper values, while also somehow simultaneously having the opposite effect of preventing the pressure to build up in the block for the switch to go off.
Maybe it could explain why my radiator ultimately blew 4 laps into my Sunday race? Or hell, maybe it was the radiator that was clogged the whole time? shrug
Som