Oil Pressure Question

[gibgoaz8]

Cranked up the 77 FJ40 yesterday and noticed there was no oil pressure reading on gauge. Shut engine down and starting looking. Took gauge cluster out and checked continuity of wire from oil sending unit to wire on plug that goes to oil pressure gauge and had good continuity. Screwed oil filter off and cranked up cruiser and oil was pumping very good up through oil filter housing so I don't have an oil pump problem, thank goodness. So, I believe that I have a oil sending unit problem or an oil gauge problem. How do I check each one to isolate the problem. Thank you very much..

 

[bsmith123]

oil gauge

disconnect the wire and put an ohmmeter on the op sender and see if resistance lowers when you fire it up

for the gauge you can probably touch the wire to ground and see if it maxes out for pressure

Power passes through the gauge to the sender to ground---the higher the op the lower the resistance of the sender which the gauge translates to the needle

I had a motorcyle direct reading gauge in my garage I took the sender out and screwed that in