Oil gauge went kaput

[driver007]

I was doing some altanator work and the oil sending unit got unpluged. The po said the sending unit was new. The gauge bounced around but worked now it is dead. The light still works in the gauge. Were should I start to look to trouble shoot. I am going to get a new gauge, but was wondering if a ohm meter might tell me anything? Fuse perhaps Were would it be in the fuse box?

 

[BusaDave9]

Sounds like a bad connection on the sending unit. Especially after you worked on the alternator. I had the same problem. On the highway the needle would bounce down to 0. I knew the oil pressure couldn't fluctuate as fast as the needle. The sending unit has a threaded post that the connector presses onto. I removed that connector and put on a crimp on connector and held it on with a nut.

 

[driver007]

Thanks Dave any chance of a pic? I am not clear. I take it you removed the splay blades and used crimp ons. I have not taken one apart yet hense my not knowing. Thanks for your replie.

 

[BusaDave9]

On the right side of the engine is the oil pressure sensor (sending unit).

The connector on the wire just presses on the threaded post on the end of the sensor. I am willing to be the wire just came off.
Here is another picture showing the threaded tip.


If the wire came off you can press it back on but if it is loose you may want to change the connector to a crimp on connector then use a nut to hold it on.

 

[driver007]

Any chance it would be a purple wire? There is a loose purple one might be the fix I will check when I get home

 

[mtnwhlr]

When mine started having problems I went to Autozone and bought a mechanical gauge with a white face. Now I know it's always reading right and I can read it at night. I'm going to get the matching volt gauge next. I think they look so much better and I like being able to read them at night.

 

[DHugg]

Any chance it would be a purple wire? There is a loose purple one might be the fix I will check when I get home

Driver007, I had a purple wire hanging loose in the engine bay when I got my '80 CJ7 home, and no oil pressure reading. I put a new connector onto the purple wire, looked at the wiring diagrams everywhere I could find one, then clamped the purple wire to the top terminal of the oil pressure sending unit.

Now I got oil pressure.

 

[phinleft]

Driver007, I had a purple wire hanging loose in the engine bay when I got my '80 CJ7 home, and no oil pressure reading. I put a new connector onto the purple wire, looked at the wiring diagrams everywhere I could find one, then clamped the purple wire to the top terminal of the oil pressure sending unit.

Now I got oil pressure.

X 2 funny thing is i replaced my starter sunday and pulled the same wire by accident too.

 

[driver007]

Well I am in good company. Never got to it I pulled off the bumper that the po had on. Sparks a flying. I will reinstall the purple wire tommorow. thanks guys sounds like it is a common thing that happens when working on the alt etc.

 

[bill92250]

When mine started having problems I went to Autozone and bought a mechanical gauge with a white face. Now I know it's always reading right and I can read it at night. I'm going to get the matching volt gauge next. I think they look so much better and I like being able to read them at night.

what kind of hose/tubing does that mechanical gauge run? I had a rather unhappy experience with a copper one after a day on the trail.

 

[mtnwhlr]

what kind of hose/tubing does that mechanical gauge run? I had a rather unhappy experience with a copper one after a day on the trail.

It came with a plastic one. I just made sure it wasn't aginst any sharpe edges and have had no problems with it. I just don't trust any thing but machanical gauges and will change over to them whenever I can. Plus the stock ones in the Cj are hard to read at night and these with the white face and better light are very easy to read at night. And you know what it says is true.

 

[bill92250]

Like fuel line?

 

[mtnwhlr]

Like fuel line?

No it's real small and looks white but you can the oil in it.

 

[driver007]

I found the purple wire and reattached. I never seen a wire attach buy just sliding on like it does. I will change it to a loop when I do the motor next winter in between ice fishing trips. thanks for the info boys.