[Shotimes] ECT failure

[van Oss]

My 91 was running badly (stalling, bucking, etc.) and running hot.  I fixed
the radiator fan motor, and it would run during KOEO.  But it would not come
on when the engine got hot.  I replaced the ECT, and now the fan comes on as
it should.

The ECT is a thermistor.  Resistance is inversely proportional to temp.
According to Probst, a cold ECT (-4F) would be 14,600 to 17,800 ohms, and an
ECT at operating temp would be 290 to 350 ohms.

Measuring resistance across the old unit, at room temp, it's about 36,000
ohms.  I'm guessing the PCM thought the engine was colder than Hillary's
blood (uh, that's Sir Edmund Hillary to you, buddy) so the engine was
running ridiculously rich.  That might explain the fuel smell and the fact
that, after stalling, it would start only with the throttle all the way
down, turning off the injectors.

Does this make sense?

Joseph

p.s. Once again it's a 91 3.0L MTX with 140K, 73mm MAF with Ted Breaux LPM.
I wonder what the fuel curve of the LPM says when the PCM thinks the engine
is at 80 below.   :-)   Never got around to just pulling the LPM so I don't
know if it's a factor in the way that the PCM interpreted high ohms on the
ECT.