[JordanH]

I replaced my oil sending unit on my 302 but when the engine is running the gauge doesn't move. I have grounded the wire and the gauge pegs so I know thats not the problem and since I have driven it plenty of times I know the engine is getting oil. Anything else that could be causing this problem?

Thanks in advance

 

[Veronica]

Hello. It sounds like you might have bought a bad sending unit.

 

[Ivy66GT]

A bad sending unit would not be unheard of. This is one item that you should not replace unless there is truly something wrong with your old one. An original, old one likely works better than the new replacement.

http://www.allfordmustangs.com/forums/classic-tech/158024-oil-gauge-senders-v8-what-expect.html

 

[Print Dad]

Hello ALL,
First - - I highly agree with the others that you likely have a bad sender.

Next - Ivy - -thanks for the great link and very interesting info. I wish I knew about this stuff

My only kinda goofy idea is if the sender were installed with teflon tape - -perhaps you should try liquid teflon. I understand that the threads on the sender should cut the teflon and make a good ground - -maybe it is possible that too much tape would cause a situation where the sender is not making a good ground.
I will wait to hear from Ivy or Veronica on this one -but juts a goofy thought

Print Dad

 

[Ivy66GT]

Too much tape might be the problem...but I doubt it. I use teflon tape on mine and the threads always seem to cut through it and make good electrical contact. The senders today just aren't very top notch.

Use your Ohmmeter to measure between the sender body and the engine block. If its less than an Ohm that isn't your problem. The sender should operate in the 10-100 Ohn range so another Ohm wouldn't make any difference in what your gauge reads.

Without an Ohmmeter remove the sender lead and short it to the sender body; you should get the same results as it you shorted it to the block. I.e., full scale needle deflection. If so, the problem is inside the sender and not with its threads.

 

[JordanH]

Thanks for the replies!! I guess I'll try it with less teflon tape and see what happens. Sadly the engine had a switch for an idiot light so the new sender was needed. When I replaced it no oil came out of the hole, is that normal? It seemed odd to me that none would drain out.

 

[Ivy66GT]

That probably depends upon how long it had been since the engine ran. There has to be oil in the hole you use for any sender to work. If none ran out I would at least investigate to make sure I had the correct location.