I've been searching the forums but so far I've been unable to find an answer to his... I bought an 88 Formula 350 a few weeks ago and noticed that the oil pressure guage wasn't working. Stopped at the parts store for something else and picked up a new oil pressure switch, assuming that it was probably bad. When I crawled under the car to change it, I found the part I bought didn't match the part on the car, so I did a little digging and came up with this...

The switch I had was the correct switch for my car if it came with the guage (1/8 NPT threads and a 1 wire connection)

The switch on the car is the one that is supposedly for an oil pressure light (1/4 NPT threads and a 2 wire connection)

The pigtail is the 2 wire version for the switch that's on the car, but when I got the part that fit my car, the guage still doesn't work. It moves a few PSI when you start the car, but that's about it...

I am going to get a mechanical guage and check the actual oil pressure, but I really suspect some other problem.

I was wondering if anyone had encountered anything like this before...

Anyone have any thoughts?

 

There are two oil pressure measurement devices on these cars. One is directly above the oil filter and is usually a weatherpack connector. this sensor is the fuel cutoff sensor (cuts off fuel if oil pressure drops below 7 psi or so). then you have the gauge sensor which is screwed in to the rear "china wall" of the block. it has a small can type of apperance and has a single spade connector.

I think you might just be looking at the wrong part on your car.

 

That fuel cutoff switch doesn't do what you say. It is an oil pressure switch that activates the fuel pump if the Fuel Pump Relay goes bad.

Back to the question at hand,
The cars with the sender above the oil filter is a switch and a sender I believe and I think it has 3 wires.
If it has 2 wires, it may be just a sender or switch and there should be another sender or switch on the china wall behind the distributor.

On my 86, I had the sender and switch that screwed into a Y brass fitting on the back of the china wall.

I've got an 88 Formula 305 and I'll check to see what sender/sensors I have on that.

 

The oil pressure SENDER is what you want...it is on the back "wall of china (lol)" by the distributor. If you goto the parts store asking for an oil pressure SWITCH guess what...you'l get a switch! Sorry for the sarcasm, anyway, you need a SENDER or SENDING UNIT.

 

Thanks for all the input - gotta get a shop manual soon!

Actually I asked for the sender in the first place and got a switch. On the plus side I needed the switch as well, one of the contacts was broken off in the connector...

And I found the sending unit, back on the China Wall...so it looks like I'm off to the auto parts store again.

Thanks again all