Can someone fill in the blanks here for me for ECT failure- I'm trying to trace down no fast idle on cold start and a slightly rich mixture, but with good power, driveability.
Scenerio 1:
ECT has a broken wire and so reads 0 volts (means engine hot) so no fast idle on cold start, computer compensates by leaning out mixture, O2 sensor indicates more fuel required so computer compensates by enriching mixture. Where am I too rich or too lean?
Scenerio 2:
ETC has a bad ground and so reads 12? volts (means engine cold) so fast idle on cold start, computer compensates by enriching mixture, O2 sensor indicates less fuel required so computer compensates by leaning out mixture. Where am I too rich or too lean?

Ron
87 745 260000km
near Brantford, On,Can