Oil pressure switch or sender tests OK - what else could be wrong?
So whichever oil pressure sensor you have it seems OK. You tested your oil pressure switch or tested your oil pressure sender or tested the combination oil switch and sender - and you have determined that they are working correctly - we always suggest trying another just to make sure.
What next? What other issues could be causing problems?
Next you should check your generator controller wiring - make sure the generator wiring is correct and the switches and senders are connected to the correct inputs on the controller or ECU. If the sensor in question connects into the ECU, you won't be able to do much more - call the engine manufacturer for assistance.
If your oil pressure sensor connects tot he generator controller, you can test the inputs and check the readings.
If the sensors test OK and the controller looks OK, then you might have a genuine oil pressure fault. Which only really leaves a few things things. If you can't find it you will probably want to call the engines manufacturer again or their local dealer.
Low Oil Pressure from Low Oil Level
Low oil level in the engine will cause low oil pressure, why do you think you have to keep the engine oil level at the recommended level? Top the oil up to the correct level.
Low Oil Pressure from Wrong Oil Type
The oil you use in your engine could cause a low oil pressure for your engine. If you are using a 0w-20 oil SAE on an engine that requires 5w-50 oil you could get a low oil pressure when the engine is hot. Some engines do have a larger bearing play and require a thicker oil to get the correct oil pressure.
Low Oil Pressure From old Oil
If you haven't changed the oil recently, check it. Is it flowing freely, is it as you would expect it to be or is it thick like tar? Oil that doesn't flow cant be pumped by the oil pump.
Low Oil Pressure from Stuck Pressure Relief Valve
The engines pressure relief valve is there to stop the oil pressure going too high - if the relief valve is stuck open then the engine won't have any oil pressure. If your engine has a relief valve, check its closed.
Low oil pressure from worn big end bearings
If there are leaks in your engine such as small leaks in the gap between your engine bearings the engine will lose oil pressure because of oil coming out of the oil channels. Hence, excess clearances between the bearings as a from excess bearing wear will cause a loss of oil pressure, especially at lower RPM as the oil pump is spinning at slowest speed.
Low Oil Pressure From A diesel leak into oil
This could be from a few places, but its likely from the fuel injection pump, especially on older engines. Diesel can leak from a seal in the injection pump or lift pump into the timing case and dilute the oil. Check the oil and make sure the level isn't rising - high oil level indicates a problem.
Low oil pressure from sheared oil pump drive
An unusual cause but it will of cause show no oil pressure at all as the pump stops turning. It can happen and means that no oil if flowing round the engine.