Oli Sending Unit

[DirksCuda]

I just put a new sending unit in my 340 70 Cuda with the ralley gauges. I got the power at the gauge itself its back to 6 volt at the gauge. Should the needle move as soon as the car starts or does it have to warm to operating temp. Also should ther be power at the wire where it plugs on the unit Thanks for any help Dirk

[70chall440]

The needle should move pretty much as soon as the car starts and the engine builds oil pressure.

What do you mean by "power at the wire"? If you are asking if there is say 12V on this wire, then no. The sending unit is a variable resister, so as oil pressure builds, it changes the resistant between the feed wire and the ground which makes the needle on the gauge move. To test the gauge, you can ground the wire temporarily and the needle should move upwards. This is just to see if the wires are connected and if the gauge moves. If that is good, you can test the sending unit by blowing air into it (see pic)

[DirksCuda]

Its a brand new unit so u would think its good but who knows. I will try the ground to see if the gauge is working. I cant see how u can blow air threw the unit . There is just a very small hole in it. Maybe I got the wrong sending unit Thanks 

[JayBee]

If your oil pressure sending unit looks like this one, you have the right one.

[70chall440]

You would blow air into the small hole in the bottom. I cannot say that I have ever done this as I always run a mechanical gauge and if the stock one isnt working, then it typically is a bad sending unit.

Does your gauge move at all?

[DirksCuda]

My gauge looks like that and im running a mechanical one also. Just trying to get the orginal working. I tried the grounding the feed wire ,that didn't work so it might be the gauge Thanks

[70chall440]