GM Oil Pressure sending unit ohms

[Bluespringscjw]

I have a 1970 FJ40 with a small block 350. I’m not sure of the year of the motor. I’m trying to find out the operating ohm range for the oil pressure sending unit. I can’t seem to find the answer anywhere. I’m new to the mechanic game so over explaining is welcomed.

 

[BILT4ME]

I have a 1970 FJ40 with a small block 350. I’m not sure of the year of the motor. I’m trying to find out the operating ohm range for the oil pressure sending unit. I can’t seem to find the answer anywhere. I’m new to the mechanic game so over explaining is welcomed.

Do you have any block information such as a casting number or anything to identify the engine, secondly the pat number of the oil pressure sending unit?

Many of the GM "old school" engines up through 1972 had actual oil that went to the gauge. I don't know what the FJ40 has for a gauge, but is it an electrically actuated gauge or is it an oil actuated gauge?

 

[PAToyota]

It's going to be hard to get specifics on a part without some specifics about what part it is...

 

[Bluespringscjw]

Do you have any block information such as a casting number or anything to identify the engine, secondly the pat number of the oil pressure sending unit?

Many of the GM "old school" engines up through 1972 had actual oil that went to the gauge. I don't know what the FJ40 has for a gauge, but is it an electrically actuated gauge or is it an oil actuated gauge?

It is an electric gauge. It is a 010 block.

 

[BILT4ME]

Well, then for reference, do you have a sending unit part number?

I would look up the p/n for a 1978 Chevy K20 350 4 speed, PS, no AC.

I would think that would do it.

I do not know the resistance across either, but you should be able to find it based on part number and specs.

Remember, Toyota switches the ground side of the load, not the hot side.

Do NOT put thread sealant or Teflon tape on the threads of the sensor, as that is part of the circuit.

That appears to be a 1970-1975 range 350 4 bolt main block.

 

[PAToyota]

Ok, for a rough starting point, see if you get these results:

The Oil Pressure Gauge Needle Should Point to:
Left Line (Low, 0 PSI) when sender resistance = ~0 Ω
Middle Line (30, 40, or 50 PSI) when sender resistance = 30 Ω
Right Line (High, 60, 80, or 100 PSI) when sender resistance = 60 Ω