Low oil pressure on 1997 Cat 3116

[drprunner]

I'm getting a low oil pressure signal on my Cat 3116 starboard engine and it's shutting down my engine. I know it's not the sensor because I swapped the sensor with my port engine and I still got it on the starboard. Also, I know I don't have low oil pressure because I clear the alarm and re-start the engine, and the gauge on top of the engine shows normal pressure, so I disconnected the wire to the sending unit and the boat ran perfect for 165 miles. By the way, the gauge on top of the engine is not connected to the sending unit but gets its reading direct from an oil line run to it. Oil level is fine. I think its an electrical issue somewhere between my sending unit and my dash gauge.

Any ideas of where the problem could be?

 

[Strecker25]

I'm getting a low oil pressure signal on my Cat 3116 starboard engine and it's shutting down my engine. I know it's not the sensor because I swapped the sensor with my port engine and I still got it on the starboard. Also, I know I don't have low oil pressure because I clear the alarm and re-start the engine, and the gauge on top of the engine shows normal pressure, so I disconnected the wire to the sending unit and the boat ran perfect for 165 miles. By the way, the gauge on top of the engine is not connected to the sending unit but gets its reading direct from an oil line run to it. Oil level is fine. I think its an electrical issue somewhere between my sending unit and my dash gauge.

Any ideas of where the problem could be?

I didn’t realize the monitor could shut down the engine. Are you thinking the sea ray monitor system is causing the engine to shut down? What does the dash gauge say?

I would see if you can get a hold of another analog pressure gauge and hook it up to the sender directly with a short wire and see if it reads properly. As you said, it’s likely not the sender, and could be a short or bad wiring between the engine and the helm.

 

[mrsrobinson]

I don't have an answer for you, but you're a riskier man than I am disconnecting the oil gauge at the helm and running the boat for 165 mi.

 

[dtfeld]

Two separate systems. There is a pressure sender that drives the gauge at the helm but no alarms triggered. A pressure switch drives the SR Systems Monitor. It will sound an alarm on low oil pressure, but it doesn’t automatically shut your engine down.

I think what is happening is your starboard is dying/shutting down and your getting a low oil pressure alarm from your System Monitor just as it should work.

The real issue is, why did your engine stop?

 

[Strecker25]

Two separate systems. There is a pressure sender that drives the gauge at the helm but no alarms triggered. A pressure switch drives the SR Systems Monitor. It will sound an alarm on low oil pressure, but it doesn’t automatically shut your engine down.

I think what is happening is you starboard is dying/shutting down and your getting a low oil pressure alarm from your System Monitor just as it should work.

The real issue is, why did your engine stop?

this makes more sense, I couldn’t think of a way that SR monitor or any onboard stock monitor could shut the engine down.

 

[dtfeld]

Both of the electrically driven systems above are separate from the mechanical pressure gauge on the engine, except they all measure pressure at the same point…on the oil gallery.

first indication of an oil pressure problem should be your helm gauge. If you get a low oil pressure alarm on the System Monitor, you have likely already toasted your engine. I think the trigger is set at like 10 psi. Regardless, it’s very low.

 

[ttmott]

Low oil pressure seen and engine shut down noted.
Swapped oil pressure "sensor" and problem stayed with engine.
What "sensor"? The gauge sender or the oil pressure switch for the SR Systems Monitor?

Alarm was on the Systems Monitor. Cleared the alarm and engine ran.
Removed wire from the "sensor" and engine ran fine for 165 miles.

I'm confused.....
First, as @dtfeld says the Oil Pressure sending unit only drives the helm oil pressure gauge - nothing else.
Second the Oil Pressure Switch only sends a signal to the SR Systems Monitor - nothing else.
Unless this engine is the later 3126 electronic there are no sensors or monitoring system that will shut down the engine; human intervention is the only safeguard. The SR Systems Monitor does not control anything. Disconnecting the OP sensor wire and clearing the Systems Monitor alarm and the engine running normally is happenstance.

The fact the engine restarted normally indicates it didn't seize up due to loss of oil pressure.
I suspect you have a fueling issue and the engine RPM went so low that the systems monitor alarmed.

 

[dtfeld]

Is this happening when the engine is cold? Hot? Both?