xviper

You're not really going nuts. They are related to some extent but here's how:

The Idle Air Control senses coolant temps from coolant lines that circulate around it. This is the same circuit that feeds the throttle body. This coolant circuit is a separate one that is there for that specific purpose. The ECU takes the coolant temp from the sensor in the head near the back of the engine, next to the firewall. Having taken readings from both, I can tell you that the temp of the coolant in the throttle body/IAC circuit lags about 15 to 20 degrees behind the temp of the coolant at the sensor. The IAC is calibrated to lower the idle based on a whole different temperature than what the ECU sees at the sensor to determine VTEC ability. My last observation of the sensor temp reading would indicate that "3 bars" lights up at the precise moment that the coolant temp hits 75*C. This is not saying that VTEC is allowed once the temps gets to 75, but rather, this is where most people observe that they can VTEC (when they see "3 bars"). Depending upon the calibration of your "bar gauge", you could VTEC while still at "2 bars".

mwilly00

Dang. Thats why your king. Thanks for the education. Have a good easter