Engine temp alarm

[Rich Wood]

Cummins 6cta, 1997 Ran engine on the hard for 15 minutes prior to launch, no issues. Ran day before launch, high temp gage pegged over to far right, alarm light and siren go on, after running for two minutes. Shut it down, stated up again, all ok. Launch next day, fine for ten minutes, then gage pegged over, etc etc. Gage does not creep slowly to right, as if temp was rising slowly, but just buries itself fast. Raw water is circulating fine, engine temps are fine via infrared thermometer. Movement of gage to right is sporadic, it shows normal, then goes far right. Next day shows normal, in two minutes goes to the right. I disconnected the wires to the actual engine sensor and the problem still exists, leading me to believe the sensor is ok. I have a new gage, which I can install to see if it’s the gage. It might also be the alarm circuit board which is mounted behind the tach, don’t know how much that will cost. Could also be some shorted out wires. Any suggestions?

Topic

[Bill Desmarais]

Rich,
If you want a “real” temp alarm you should consider a 205F temp switch and an
Aqualarm or Borel alarm panel to wire it to.
Very easy to do and you won’t have to rely on the Cummins factory panel alarm algorithm to save an engine.

Here’s a post I did a while back with a response from Rob

6BTA 370 setup the "Seaboard Way"

Regards, Bill D

[Rich Wood]

Thanks, Since I bought a new gage, guess I’ll try that first, if not, I’ll  have to get someone to look for a short.

[Tony Athens]

Cummins Gauges & PCB Alarm Board

Just an FYI………………….If you have a good working factory panel,  all the gauges and all senders are working correctly, you can completely disconnect the PCB “alarm board” and it WILL NOT AFFECT the gauge readings at all.. The PCB board is only there to interpret the sender feed-back and operate the alarms / buzzer on the panel..   To me, based on your post, a new PCB board would not fix the issue you have as described.  Bad sender, bad wiring, bad gauge, or some combo of these. 2nd FYI————–The alarm board Cummins sells is “crazy over priced” and we are considering going “aftermarket” for it.. It’s worth about $25 with a MOQ of 500 Pcs with a development cost of about $1000.. Just have to look at the numbers, long term.. Tony

[Rich Wood]

Sorry, Corey, I should have ordered it from you guys, bainfart.

[Corey Schmidt]

That sounds more like it: 

https://www.sbmar.com/product/cummins-replacement-analog-instrument-panel-alarm-circuit-board-pcb/

[Rich Wood]

Follow up. I decided to order the board, called up and did it, from Cummings, $300. The guy in the morning at Cummings gave me the price for the actual alarm buzzer! 

[Rob Schepis]

Regarding your comment about the alarm board being only $80…Well you get what you pay for – I’d rather it cost double and be 100% reliable and have a REAL buzzer..

[Corey Schmidt]

Alarm board…

I agree that the alarm board is usually the culprit in many of these weird circumstances… usually a gauge will “PEG” when it loses a solid GROUND.

[Rob Schepis]

Not sure if you’ve seen this but in case you find the need there are wiring diagrams here

https://www.sbmar.com/engine-info/cummins-6cta-specifications/

[Rich Wood]

Thanks, not a pro at tracking electrical! Have to get some help. Gage coming today, and new alarm board only $80, that was a surprise. We will see!

[Rob Schepis]

Agreed that it’s not an engine/sender issue, temp senders rarely go bad, the issue is likely at the helm and likely due to ground/voltage issue.  Just need to spend time checking all..

[Author]

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