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Old 09-03-08, 05:19 PM   #15 (permalink)
Tools R Us
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Join Date: Jul 2004
Location: Chandler, AZ
Posts: 7,913
Quote:
Originally Posted by fj40z View Post
So on the way home today I was stopped at a light when I glanced down at my oil pressure and noticed it was maxed out, needle all the way to the top. While I was stopped at the light I cut the truck off and the needle never dropped, luckily I was literally less than a 1/4 mile from my house. ...
I have never seen this failure be anything but electrical. If the motor is off, key is on, the oil pump isn't pumping any oil and the gauge is reading at the top, there is a short to ground in the sensor side of the circuit. The next test is to make the same thing happen and unplug the sensor wire, if the gauge falls it's a bad sensor or insulation failure close to it, if not continue testing the wiring back to the gauge, then test the gauge. Changing the oil would be a waste of $$$.

The gauge gets power from the gauge fuse, ground comes from the sensor, open = gauge at the bottom, grounded = gauge at the top. Yours is intermittently grounding, it could be a bad sensor, wire insulation failure shorting to ground or a bad gauge.

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