Replaced fuel pump on 75 F100 360 and in doing so messed up oil pressure sending unit. Replaced the sending unit and now have no oil pressure! Any thoughts? Have current to unit. Thanks in advance. Bruce

 

Is the sending unit a big unit, or a small one? Was the original big or small? Maybe the replacement is really an idiot light switch?

 

Not sure what you mean by big or small however it is the same unit as the original. Could the new unit be defective?

 

Anything can be defective - if you have digital volt meter with an OHM range, can you test the resistance?

Does it look like this:

 

Yes sir. that's the one. I'll have to find a volt meter and test it. What should the meter read? Thanks

 

no clue, really. at least not ZERO ohms (complete short). If you can, see if you can hook a wire to it, and connect up the ohm-meter to ground and the oil pressure sender, and when running, it should fluctuate with RPM (oil pressure).

 

Don't be surprised if it's defective if it's an off shore replacement. Buy, borrow or steal a mechanical gauge to screw in temp to verify your pressure..

 

Will try that. Thanks