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Oct 16, 2008 | 05:58 PM

heathrunkles

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From: Mt. Airy MD

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Does anyone know where the PCM sees water temp? I have the scan gauge and on a cold start the temp reads around 190 slowly climbs to 236 and then the t-stat opens and it instantly drops to aroung 180 climbs to 203-205 and stays there. I thought this was odd that the temp would climb so high but I was assuming the temp sensor was the one on the water pump for the dummy gauge.

The proplem I have had today and yesterday was that the water would warm up to 233 and stay right there. The stat is not opening (no flow or heat through the upper radiator hose). Also the fan runs continuously-even on a cold start 50 degrees outside. I can make the dummy gauge move and got the engine hot(moved from the "r" to the "a" in normal, but the scan gauge only moved between 232 and 235.

I have to pick up a machine tomorrow(around 9-10,000#) and this has me worried. Any thoughts?
Thanks

Oct 16, 2008 | 06:05 PM

MADVAN

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From: Levittown

PSD does not use the coolant temp for PCM input.
Ignore it from a scan standpoint.
The coolant sensor only runs the POS dash gauge.

Bill

Oct 16, 2008 | 06:36 PM

tjbeggs

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From: Silver Lake Dunes, MI

yep what Bill said. PCM doesn't know coolant temp so the Scan gauge won't either unless you have added it as one of the analog inputs

Oct 16, 2008 | 06:49 PM

MADVAN

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From: Levittown

Quote:

Originally Posted by tjbeggs

yep what Bill said. PCM doesn't know coolant temp so the Scan gauge won't either unless you have added it as one of the analog inputs

Tj

If you add it to the SG.
Is it a 5v or 12v input/output?

Bill

Oct 16, 2008 | 07:01 PM

tjbeggs

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From: Silver Lake Dunes, MI

Quote:

Originally Posted by MADVAN

Tj

If you add it to the SG.
Is it a 5v or 12v input/output?

Bill

5v....They use standard GM senders

Oct 16, 2008 | 07:15 PM

MADVAN

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From: Levittown

Quote:

Originally Posted by tjbeggs

5v....They use standard GM senders

Thanks

Being that the OBD2 scan shows an erratic coolant temp on the PSD.
It has stopped me from trying to use a 5v input to the pcm.
The PCM has a pin for it with no wiring to the pin.
Allway's thought something would go POOF!!!

Bill

Oct 16, 2008 | 07:29 PM

heathrunkles

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From: Mt. Airy MD

I wonder what the scan gauge is reading then? It is labeled water temp. I have had it on for the last two months or so and it is consistent on every start up leveling off at 203 degrees. They screwed up programmingthe gauge from the start and it still wont read the icp pressure

I would have assumed it was water because of the 203 stat. Does yours do anything TJ?
Another though--could it be oil temp? I just put a resistor on the eot sensor yesterday and that is when it started acting up. oil and water usually run close to the same don't they?