Quote Originally Posted by matt5112 View Post
apparently the ECT sensor is a dual sender.

Sends one signal to the PCM and one to your gauge.
That's what I said !

Quote Originally Posted by matt5112 View Post
If possible it would have been interesting to see what a scan tool would have said the ECT was when the gauge read that it was overheating.

My tight control on ECT is because of the lowered fan settings.
I agree. At this point we can only speculate that the temperature the PCM observed was well below 195 * F, based on how the exhaust smelled, and it's setting the DTCs. Obviously, it did see some resistance, since it never went into it's protection mode (high speed fans).

I take it that Matt is eluding to some sort of non-stock ECT sensor (???) that forces the fans on at a lower ECT by fooling the PCM. This sounds attractive to us, but we would be concerned that the PCM would compensate with a richer fuel ratio if it thinks the engine has not warmed up. Then again, if it only changes the measured temperature by 20 * F or so, maybe the PCM won't compensate with more fuel. As it is, I saw a drop in gas mileage (and smelled a dirtier exhaust) when the PCM thought the engine was never warming up.


Then again, maybe we're talking about reprogramming how the PCM controls the fans. I like that solution better.

Any ideas ?