Oil pressure gauge is jumping at 3100-3200 rpm

[dave schilt]

I have a 1998 37 Maxum with twin 7.4 Mer. Bluewaters. When running at 3100 rpm or higher my oil gauge on starboard engine starts jumping around and the alarm engine when off cutting down for one second. This occurred three times during a 23 mile trip. I think it is the oil sending unit or a loose wire.

[dave schilt]

Oil gauge fixed by loose wire but alarm still is going off. One of the two engines still loose power when alarms goes off.

[mmwjr]

Alarm sounds when either low oil pressure, hot temp, or low gear lube. The alarm uses sensors that are separate from the helm gauges.

The engine management is putting the engine into guardian mode to protect it when the alarm sounds.

You can try disconnecting the water temp and lube level next time to see if one corrects the issue. I believe you have an electric fuel pump and since the engine keeps running I doubt it's the oil pressure switch as that would remove power from the fuel pump and kill the engine.

[dave schilt]

Okay I was also reading that the engine knock sensor wires could be bad. Would this cause the guardian mode. The mechanic also said that faulty grounds can cause problems with the EFI on my engines. I still think it is a bad sensor.

[mmwjr]

Yes the knock sensor will put it into guardian mode.

[mmwjr]

Not sure if knock sensor is tied to alarm though for this year. Do you get a constant alarm or beams?

[dave schilt]

Thanks for the help Mike. I will try this week and see. This is driving me nuts.

[dave schilt]

Looking for someone to travel from Knoxville to Clearwater Fl. in October 2016 Tenn-Tom route of course.