#5639, "RE: Megasquirt IAT and Stock ECU function question" In response to In response to 3
Originally posted by Tired2 Out of curiosity, why can't the sensor be shared? I always wondered on stuff like this.. since the input of the ECU is high impedance, and the input of the MS ECU is high impedance, wouldn't 'tapping' in to the sensor be similar to putting a volt meter on it? I guess the problem is the ref voltage, since you can't really tie the ECU's 5v ref to the MS 5v ref, etc. Maybe I answered my own question. Either way, not worth the headache, just curious why. Thank again.
The stock PCM switches between two different bias resistors for added resolution, but the MegaSquirt ECU can't detect when the stock PCM does this. In other applications, where the stock PCM uses a single bias resistor, it's possible to share the sensor as long as the bias resistor inside the MegaSquirt ECU is removed.
