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I may have stumbled upon something that probably
making it difficult for me to tune my MicroTech ECU. The ECU takes into
consideration information from the O2 sensor, water temp and air temp to make
adjustments to the ignition timing and fuel mixture settings. I hooked my
water temp sender to two units....both my voice annunciating engine monitor and
the MicroTech ECU. While I was running the engine today, I scrolled to a
page on the MicroTech ECU handheld programmer that I have not viewed
before. This page provides both engine rpm's and water temperature.
The engine rpm's agreed exactly with my engine monitor. The water temps,
however were WAY off. The engine monitor said the water temp was 180
degrees F and the ECU said the water temps were -15 degrees C. Prior to
the engine temps warming up, my engine monitor said 140 degrees F, and the ECU
said -24 degrees C. On various map pages, the cold start enrichment is set
to slowly start leaning the mixture after 50 degrees C. That would put my
REAL temps probably around 350 degrees F. Not gonna happen.
My question
is....has anyone else connected more than one monitor to a single water temp
sensor? (I have the stock Mazda sensor located in the water pump housing). I
will also check the MicroTech manual again to see if there is any place to
calibrate the water temp sensor. (I know I had to calibrate the throttle
position sensor initially for idle setup). Is it possible that one unit
would have a correct reading and another connected to the same sending unit
would be so far off? Different wire sizes making a difference?
My next step will be
to disconnect the engine monitor wire from the water temp sending unit, and see
if the ECU water temps are more in line with what they should be. Just
wondering if anyone else has connected more than one instrument to a single
sending unit. Thanks in advance for all replies. Paul
Conner
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