Oil Pressure Sender/gauge Testing

[3.2 CAB]

Hi, I am starting to have a problem with my oil pressure gauge or the sender for the gauge, when it is running, the neddle sometimes pegs out at 5 and stays there. I unpluged the wire from the sender and held it to ground, the neddle drops to 0. I attached an Ohm meter to the sender connector and the reading had a lot of variations in readings sometimes showing "open" Sometimes now when I turn off the key the needle is still pegged out at 5 till I tap the edge of the gauge then it falls to 0. Sometimes the gauge works properly, and does vary with engine speed, other times it is pegged out at 5. Does this sound like the sender is going bad, the gauge, or maybe both? BTW it is the stock gauge/sender set up, not numerical.

[Zeke]

Check your ground lead at both ends first. Might be a little tough to see where the ground wire comes out of the harness, but there usually are a few and they all attach to a stud. I could be off, because most of my knowledge pertains to earlier years, but the gauges are all powered by electrical current (duh) and the current flow must be proper. When one or another wires is not continent, the gauge pegs or reads 0. Could be that when it pegs, it just gets stuck up there.

Checking the wires first may save you the time, money and trouble of replacing a gauge or sender.

[3.2 CAB]

I am going to plug in another gauge to see what it does and also check the wire connections.

[Early_S_Man]

That sounds like a bad sender to me ... especially if you had secure connection to test leads and the variation was caused by pressure on the Faston tab on the sender!

I don't know the exact reading at rest [ 0 psi] for the gauge marked in bar [atm] ... but a numeric gauge sender is around 20 Ohms at rest and should be steady.

[Decolliber]

I had similar problem and verified that gauge was good by inserting a potentiometer ($3 at Radio Shack) into the circuit instead of the oil pressure sender. By turning knob on potentiometer and varying resistance, I could make the oil pressure gauge needle go up and down from 0 to 5. I did this both at the gauge and at the sender, to make sure it was not a faulty wire between the two.

[3.2 CAB]

I just happen to have some of those, I will try that. I am pretty sure it is the sender because, when I touched the wire to ground the gauge went to 0. I tried the other gauge also, it did the same. When tested with the meter, it was all over the place, including open. Thanks a lot.