Mystery sensor on 270 Cummins

[Kevin Carlson]

I have an 270 Cummins, Serial # 74602729. The attached picture shows the fuel/oil manifold. The silver sensor with one wire is the oil pressure gauge for the instruments. What is the one to the left (with 2 wires) and why is it so expensive ($250 in 2013 vs $20 for the oil pressure gauge).  I assume it controls the low oil pressure buzzer. Does it interact with the ECM for the electric air heaters? I have disconnected the air heater from the ECU and manually turn them on. I am having trouble with the buzzers, they won’t shut off, and I am wondering if this unit is the cause. I assume it interacts with the high coolant temperature sensor, but does the ECU manage the 2 signals from these 2 sensors? Why else would this sensor have 2 wires instead of one to just send a ground signal if the oil pressure drops?

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[Kevin Carlson]

It is a 1998 37′ Bayliner. The silver sensor on the right is the oil pressure sensor for the dash gauges. I know this because I replaced  it ($20) when my gauges stopped working. Also when I bought the boat the warning buzzers didn’t work and I had to buy the sensor on the left from Cummins ($250 in 2013), which fixed the problem. The reason I am thinking that it controls the air heaters is that the buzzer problem started happening when I went with the manual heat setup.

Sorry the correct serial # 45661773

[Tony Athens]

Oil  alarm switch &  gauge pressure sender–100% non Cummins supplied –This all OEM / boatbuilder stuff. 

[Rob Schepis]

That left sensor is in an oil port, what makes you think it would be in communication with the air heater circuit?  It’s intake air temp that the grid heaters monitor which is done on the aftercooler itself…

That there is boat builder stuff – is this a Bayliner, Meridian, or ??

Double check that ESN you posted.

[Author]

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