I swapped in a new engine and I'm having a problem. The oil pressure goes to about 10 psi on the gauge when its running. It could be a bad sender, but before I switch it I'm trying to figure out what resistance the sender should be reading at operating PSI.

 

Is that 10 at idle? I thought that the rule of thumb was 10 psi per 1000 RPM, so idle is ok. Does it raise up at ll when revved?

 

It doesn't change at all when revved. And 10 PSI at idle sounds too low, my V6 and the 305 before were both atleast 30-40. I pulled the distributor but I could have sworn I reinstalled it right- is there anyway that could be the problem?

 

Did you put sealant or teflon tape on the sender?
that could insulate it from ground and give you false readings.
something to check.
IIRC, a shorted sensor will read high so one that is not making good connection "may" read low.

 

If the distributor is seated, then it's connected to the pump. Yeah, 10 PSI while revving is too low. Is it the same sender that gave the 30-40 readings? Like JP said, if you have a good ground, and the sender wire is good, then it's the sender itself.