Hey,
Where is the oil pressure sending unit on the 302? Ever since I bought my truck, I've noticed that the oil pressure gauge doesn't move. The engine dosen't knock or tick, so I know it has at least some oil pressure. I would like to know what pressure I do have, so I was wondering if the sending unit was bad. If not, where do I hook up a new gauge? Thanks!

 

The OP sender should be down near the oil filter. It could be bad, or just unhooked.

 

Do the rest of the gauges work correctly? If no, the problem is likely with the Instrument Voltage Regulator (IVR).

The sending unit is located at the end of a 4-5 inch hex shaped rod that protrudes from the engine block just forward of the oil filter. It should have a white/red stripe wire connected to it. To test the system, with the key in the run position, disconnect and ground the white/red wire and ground it. The gauge should swing all the way to high. If it swings, replace the bell shaped sender. If the gauge doesn't swing, check for voltage using a voltmeter with the positive connected to the white/red wire and the black connected to ground. If no voltage is present, repeat the same test at pin 10 at the back of the instrument cluster. If voltage is present there, check along the length of the white/red wire for corroded connections, breaks, and replace the white/red wire if necessary. If no voltage is present, and the rest of the gauges work, check the printed circuit on the back of the cluster for breaks. If none are found, replace the gauge.

 

Thanks,
I think it is probably just the sending unit, because the rest of the gauges work good. Except for the fuel gauge. When I have it switched to the rear tank, the gauge works. When I switch to the front tank, the gauge goes to E. I think it's just the sending unit for that too, but that's a job for another day.

 

I just replaced my sending unit with a replacement motorcraft I got at oreillies for 22.00. Don't forget to wrap the threads with Teflon tape or it will leak. It's a 9/16'' wrench to remove and it is moderately difficult if your inexperienced. Took me about 10 minutes to replace because I wasted a few minutes thinking I was unthreading it by turning the housing but it turns out it turned and the threads didn't.

 

Teflon tape can actually prevent the sender from working. It has to be able to ground properly, or it won't work.
Sending units normally have a bit of thread sealer already on them.

 

Logic is correct but experience has never failed me, I have replaced dozens of sending units on all makes and models and I have never had a problem, infact the sending unit I removed had some teflon tape. The tape always works its way to the top to act as a seal

 

Used in moderation, and not totally covering the end of the threads, yes it can help seal.
Too much, and run all the way to the end of the threads, and it can prevent the unit from being able to ground. I've seen it happen too many times.