SMX Analog Instrument Panel Alarm Circuit Board question

[Mike Uliasz]

Replaced the Analog Instrument Panel Alarm Circuit Board 6 weeks back. Old alarm board buzzer did not shut off after starting.

The new one is fine at start up and cruising, but a couple times I’d get a ‘Chirp’ from the alarm board after coming down off a plane to idle/trolling speed. So I’d just disconnect the purple ignition wire, since the temp gauge and oil pressure seem fine. Is the ‘Chirp’ sound a pre-warning? Engine temp is 180 at cruise (2200 RPMS). New SMX raw water pump in the spring and aftercoolers/heat exchanger service a year age with SBMAR kit. engine # 45408232.
Thanks

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[Tony Athens]

The “chirp” also has its plus side.. It tells you the system is doing exactly as it should.

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Mike Uliasz

[Mike Uliasz]

Just a quick follow-up on how I’ve got around the ‘Chirp’ from the alarm board after coming down off a plane to idle. RPM’s at idle are @ ~575, so I just idle up a hair to 600 RPM’s and the oil pressure goes up just enough to eliminate the ‘Chirp’.

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Tony Athens

[Mike Uliasz]

Corey,
That’s it then. I’ve seen it drop down to around 5 PSI after running hot. Its around 30 PSI at idle on a cold start.
Thanks, appreciate the quick reply.
Mike

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Corey Schmidt

[Corey Schmidt]

Oil Pressure

What is your engine oil pressure dropping down to when you hear the “chirping”? Cummins engines are hi-flow and are spec’d at very low oil pressure at idle when running hot… sometimes down to 5-6 PSI. The alarm board will be set very close to that and sometimes you’ll hear a chirp as the oil pressure gets close to the low pressure threshold set on the PCB alarm board.

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Tony Athens

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