258 Oil Pressure question

[somdfisher]

I have been doing a rebuild for 2 years got it back together last year and had an oil leak. Messed with the oil pan a few times and the main seal, but I had gotten laid off so my work came to a halt with the new job. Now I am finding time to tinker again. I got the oil leak all fixed up and took her for a test drive to a friends house. I noticed while driving that my oil pressure gauge was sitting at 0. No issues or weird sounds, but it would jump between 20 and 0 the rest of the way home. My friend came over and we timed my Jeep and set the idle. While it was running I looked at the oil pressure gauge and it was sitting at zero. When my buddy hit the gas at the carb it jumped around and went back to zero. Again no noises or anything crazy happening. When I first start it up, it sits at 20 and starts showing the jumping around when it warms up. I am thinking either a bad ground, dirty connection, or a new pressure sender is needed. I was hoping to get an opinion though

Thanks.

 

[rr41mag]

what weight oil are you running? There could be air in your line running from the engine to the gauge. Crank the engine and break the fitting loose on the back of your gauge until oil oozes out then tighten it up.

 

[somdfisher]

I have 5w-30 since everything else I own takes it. My gauge has the electrical sender not with the oil line.

 

[somdfisher]

I have 5w-30 since everything else I own takes it. My gauge has the electrical sender not with the oil line.

 

[coldair]

I would replace the sending unit sounds like it if didnt have oil pressure that it would have toasted your motor by now.

 

[Casuall454]

Do you have a 1/4" "T" with mechanical hand held gauge that you can place in line for a second opinion?

If you have the electrical sending unit, that is usually the problem.

If your using the oil pressure line, I agree air in the line is the most likely causing your issue.

 

[CJim7]

The oil pressure sending unit is a small bell shaped unit that comes out of the block on the passenger side. It has a single wire attached to the top of it. Check to make sure the wire is not loose.

 

[IOPort51]

I had that problem on an 81 and it drove me crazy. all it needed was to mash the stake on that slides on the sending unit with a pair of pliers just enough to make good contact and it went away.

 

[somdfisher]

I checked the connections at the sending unit. I plan on actually putting a new connector on there and clean it with electrical connection cleaner.

I know I am getting oil since I opened the oil cap and can see the oil on the valve train.

It only goes to 0 once the engine warms up, when it is cold it shows a little over 20psi. I'm thinking its going to be the connection or the sender. While I was driving it the gauge was jumping from 0 to 20 intermittently. I thought grounding at first but the heat in the engine wouldn't mess with that inside the cab. I may even run dry line (temp line from sender to gauge) just to check that out.

I appreciate your help.