After doing some internet research, I found a re-ocurring theme. "Loss of oil pressure due to oil sludge". Therefore, I decided to backtrack and start with the oil. The oil was about 1/2 quart low and dirty. I added engine flush to the oil and let it run 10 minutes. Hoping to loosen up a possibe obstuction in the oil pump pressure relief valve or sludge accumulation on the pick up screen. Next, I completed an oil change, spending a few extra dollars for a Mobile 1 oil filter. Took the truck out for a test drive and the oil pressure seemed to stabilize; that is, the oil pressure stiopped dropping to "0". After warming up the engine, the oil pressure at idle was 40 psi and the pressure under load was 60 to 70 psi.
I have to admit that I did not test the oil pump pressure (do not have a mechanical oil pressure quage, although, I did find one at NAPA for 20 dollars). Tested the harness wiring athe the switch and found 1.2 ohms (continuity) on the sensor ground wire and.0035 volts on the power side (from the ECM). Engine switched on, but, not running. I have a suspicion that the pressure is still too high and anticipate bearing or seal problems in the future.
Friday, December 18th, 2009 AT 9:13 AM