oil pressure problem

[Dav]

I put a fb marketplace motor in my '88 Ranger. The original motor blew the head gasket I think. Was on the Interstate and got the nasty smell and a bit of steam. popped the hood to find water and oil around the battery area. The newer motor (he said 1990) runs but the oil pressure light stays on. Before I installed the distributer, I pre oiled with a cut up dist. I checked the oil level before and after pre oiling and there was a significant drop in level, indicating it had pumped oil. I don't want to run it w/ the oil symbol lit up. I am not sure which sending unit I put back; can the sender get air bound? If I pull the sender and crank it over, am I going to get a bath or does it just dribble? I had enough trouble getting the dist to seat that I am sure the oil pump shaft is seated in the bottom of the dist.

 

[rusty ol ranger]

I put a fb marketplace motor in my '88 Ranger. The original motor blew the head gasket I think. Was on the Interstate and got the nasty smell and a bit of steam. popped the hood to find water and oil around the battery area. The newer motor (he said 1990) runs but the oil pressure light stays on. Before I installed the distributer, I pre oiled with a cut up dist. I checked the oil level before and after pre oiling and there was a significant drop in level, indicating it had pumped oil. I don't want to run it w/ the oil symbol lit up. I am not sure which sending unit I put back; can the sender get air bound? If I pull the sender and crank it over, am I going to get a bath or does it just dribble? I had enough trouble getting the dist to seat that I am sure the oil pump shaft is seated in the bottom of the dist.

I would hook a real gauge to it and see what your pressure is.

If its not noisy its probably the wire or the sender. Your truck has the idiot light for oil pressure instead of the gauge? I think the senders are different between the two...which is probably the problem.

 

[SenorNoob]

IIRC the gauge sender is significantly larger. The light is just a switch that's supposedly set for 5lb.

 

[Dav]

You nailed it, and I give you Thanks!
I changed the o p sending unit and the light is gone. While I had the old one off, I cranked it and got oil out of the hex extension, just to be sure.
The sending unit that did not work was tan, the one that does is black. Whether that indicates which is which I do not know because the colored cover unscrews from the unit and they are both black underneath.