Hello,


I have a problem with my oil pressure or hopefully just the
gauge.


The gauge was always flaky, like going from the middle 275
KPA to 1/3 on the gauge and then shooting back up to ¾ on the gauge in normal
highway driving. (Max on the gauge is 550 KPA). In last few days I have just
put over 4000 Km on the truck.


Before the last 2K I have changed the oil from 15W 40 semi
synthetic to 0W 40 Shell


Rotella full synthetic .On overnight stay in –18 C<span style=""> </span>(0 F) the truck started right up with high
oil pressure. When I got home and started the truck the in the morning the oil
pressure was 0. Well I have disconnected the OPS, which by the way was replaced
before the trip and the gauge shot up way past the 550 KPA. Plugged the OPS
back in the oil pressure still 0 with a CHECK GAUGES light on. After about 15
minutes the oil pressure gauge shots up to ¾. Took it for a spin and under hard
acceleration the gauge gets buried like with OPS disconnected. This happened in
last 2 days. The truck has lots of power and uses almost no oil. What about
wiring in aftermarket oil pressure gauge.


Any help would be greatly appreciated.

Do some testing on the OPS connector to see if you have 12v power on the orange all the time, and nothing (infinty ohms ) on the yellow and grey.


I had this problem on a newly replaced OPS switch. It melted the plastic between the connector pins inside and was shorting out internally.

I'll assume that you've ruled out an actual no-oil-pressure condition. Tone of the engine wasn't abnormal right? This was also the first time that the truck displayed this condition... correct? If all this is right, I'd bet QM is on the right track.


BTW, if you happen to replace the OPS for some reason, expect the reading to be somewhat different than that of the original sender. Mine used to show 45lbs engine hot at highway speed...now about 55lbs. Makes me feel better about that low reading at idle http://dieselplace.com/forum/smileys/smiley2.gif


Jim

Ya, that spring inside gives all different kinds of readings when you replace it. Some people preach that you should only use the OEM ones, because they feel that the generics aren't as good of quality. Truth or tale? for you to decide. If the OEM was really worth it's salt, then it would be rated an extra 1/2 an amp to keep from meltin' down with lift pump current.

If your oil pressure guage is erratic and you want to isloate it from
the OPS. First remove the connection at the OPS and check for voltage
at the Tan wire. This will check the wireing through the guage. If good
and constant put an ohm meter, on the lower scale, on the OPS at the
point where the tan wire would go and ground out the meter. Have
someone start the truck and watch the ohm meter. The resistance should
change as the oil temperature increases.



The Orange and Gray wires at the OPS have nothing to do with the oil pressure guage they are the wires of the fuel pump circuit.

Thanks guys,


I am pretty sure that my oil pressure is OK. The engine does
not sound any different with the gauge at 0 or 30 lbs (275 KPA). And also, before
I replaced the OPS the oil pressure was fluctuating (the gauge) but never went
to 0. That happened only after the new OPS.


<span style="font-size: 12pt; font-family: &quot;Times New Roman&quot;;">I will measure the voltage tonight</span>