Oil pressure sensor help

[SicC10]

Ok I just bought a 85 gmc with 305. Don't think it's the factory motor. Anyway I have this sensor in the back on manifold that I just replaced with single wire connector. Do these trucks have a sensor for a oil pressure light the. Another for the gauge? Or is it one or the other?

[VileZambonie]

Are you saying the one you have looks like the one pictured? Do you have a gauge or idiot light?

Oil pressure sending unit is for the gauge, oil pressure switch is for the electric choke.

[SicC10]

I have a gauge but doesn't seem to work. It's pegged to the far right past 60. So where is the sensor for the gauge located? I've only found the one I pictured and it's on the rear of the intake next to the distributor.

[Rattler12]

The one in the picture is just an "on-off" type switch used in vehicles with idiot lights. The sender for a gauge set up is entirely different. Both can be mounted in the block next to the distributor or can also be mounted in the block right above the oil filter. I had to use a 45 degree bend for the gauge sender in my 350 37 pu to angle it away from the block to keep from hitting the HEI dist.

[Spoonbill]

I have an 87 r10 305tbi 700r4 and I have the same issue. One day the gauge worked and then it just pegged past 60. I found the same part you did and replaced it and nothing so exactly where do we need to look and what color will the wire be?

[Spoonbill]

I have a similar looking sensor in the block right between 1 and 3 spark plugs

[VileZambonie]

That's the cylinder head not the cylinder block and is the coolant temperature sending unit.

Oil pressure sending unit - for the gauge has a fat body. Oil pressure switch has two terminals and for tbi systems is used as a backup for the fuel pump relay.