My ignition advance potentiometer is not working correctly. With the key on and engine off my potentiometer at full ccw I get +5 degrees timing offset, turn the one turn pot ccw 15% I get 0 degrees advance, turn the pot to 30% I get -5 degrees timing. What is going on? I have the GPI1 set to -5 deg and 5. Initially thought was that we had a non linear pot but based on the voltages list below; I don't think that is my problem. Anyone have any suggestions?

Fully CW the GPI voltage to ground was ~5v

Fully CCW the GPI voltage was ~0v

Moved to the middle was ~2.47v


________G22 pin______pot pin 1 (ground)

________G16 pin______pot pin 2 (wiper)

________G3 pin_______pot pin 3 (5v)

Software WinTEC4 version: 4.8.20

No one??

I am running timing plus the fuel potentiometer, can't remember what the setting are but will try to check them tomorrow. I do like them though.

Vergil

Okay, I'll bite.

I'm going from my knowledge of the pre-WinTEC4 firmware, but I doubt that this piece has changed.

As I understand it the Advance Trim function is setup such that

0V => -30deg of timing,
2.5V => 0deg
5V => +30deg

The upper and lower timing limits don't change this scaling, they simply limit the timing change that the function can cause. So, if you set your limits to +/- 5deg, then it should act like this:

0V => -5deg
2.08V => -5deg
2.5V => 0deg
2.92V => +5deg
5V => +5deg

So basically + and -5deg of added timing always happens at the same voltages, it's just that nothing more happens after that. Make sense?

Thanks TimZ.

Vergil

Sorry for the late reply; but thanks TimZ for your insight. I have been working with what had and it seems to work ok just not how I initially thought it was going to work.

Mike