I have a 1971 FJ40 and the oil gauge is no longer reading. I installed a wet gauge (shows good oil pressure) and started trouble shooting. According to a U-Tube video they said to check the gauge take it to ground and the needle should move to the high side and mine does. I created a test tool (potentiometer) and came up with the following. The needle is dead on the H @ .2 ohms, on the high tic mark @ 10.1 ohms, on the low tic mark @ 30.2 ohms and on the L @ 41 ohms. I also checked that the sending unit is grounded (ohm meter lead to a bolt on the frame and one to the sending unit case and had a reading of 1 ohm). I replaced the sending unit with an after market unit from SOR and have the same issue. And neither unit is shorted from the unit casing to sending unit pick up. Looking for help.
Oil Pressure Gauge
- Thread starter Flash167
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
typically with these types of gauges if you ground it and it goes to high or full then the gauge itself is good. Then it's either sending unit, ground or wire between.
Can you run a temporary wire between them to test.
Can you run a temporary wire between them to test.
Same for mine. I did a direct read gauge in 83. I seem to recall that the amp meter might have the voltage supply (reducer/regulator). If you look around there are threads about fixing the issue. Coolerman? comes to mind.
- Thread starter
- #6
The wire is good between the gauge and sending unit as explained in my initial post. Was able to get the gauge to move through the entire range using a potentiometer using the wire that runs from the sending unit to the gauge. The ground is also good as tested from the sending unit case to the frame at 1 ohm which is next to nothing. Can’t believe that the new sending unit is bad but any thing is possible. I’ll try the lightbulb test described in the other post.
Were you able to find anything here?
New parts these days don't seem to have the quality control that people with pride made, now it all profit motivated with no other consideration.