Yanmar BY4 180 Electronic short

[ALICE J]

ALICE J is an R 27 2011, 2600 engine hours, developed electronic short in which the instrument LED panel went gray, it would not activate. Checked the oil water and fuel which were necessary for all diesels proceeded to Georgetown Exuma. Contacted Mastry Marine in Tampa who suggested a new LED screen. New screen installed but the alarm would not shut off. Contacted Marine Diesel Ltd in Nassau New Providence, and Tech said he would have to come to the boat. The tech arrived and started tracing circuits. Tech determined that there was a short somewhere in the communication cable between the LED screen and the ECM on the engine; solution is a new cable.
Now the interesting problem the tech noticed that the high-pressure fuel solenoid relay had been burned. I said I had replaced that unit three years ago after it was diagnosed as my starting problem. I asked the tech why this relay would be burned he said because it was drawing too much current. I said why was the drawing too much current his explanation was fascinating he concluded that the short that I had in my present wiring had led to the overheating of the relay. The new relay was from Napa and not a certified Yanmar part which may explain why it has not burned over the three intervening years. Apparently the short/corrosion had reached a point where the LED screen would no longer function. The tech also indicated that when the high-pressure fuel pump relay malfunctions it is a symptom of a hidden problem. The text said the hidden problem would have to be traced out using a computer scanner and lots of patience. Presently heading back to Nassau where a new cable will be ordered and I’ll have the tech make sure all systems are working properly..

 

[knotflying]

Interesting occurrence. I think before I started pulling a new cable I would hook up the new one to the components and see what happens and make sure the problem is cured with the switch. Snaking a cable all the way to the helm and then finding out that wasn't this issue will be a costly and timely effort in futility. Let us know the outcome. Also curious if you were able to get the engine info on your Garmin.

 

[Texas Tuggernaut]

Following. We have the same engine. Thanks for these details.


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[jwake]

I’m having a alarm problem and suspect a short in the communication cable between the LED screen and the ECU.
The engine starts with no alarms but when I put it in gear I get the Neutral Protect alarm. I have check the neutral protection switch and it is working correctly. I have also clean all ground connections and added a ground wire from engine start battery to the engine. I’m now suspecting a ground short in the communication cable.

What was your final out come with your issue?

 

[ALICE J]

I’m so glad you asked. Page two, the rest of the story. Turns out I was not getting power to the LED engine control box. The reason there was no power getting to the led panel is that the pin connections that come out of the EMC box the power wire had become disconnected from one of the pins internally. This was rectified by bridging the pin connector going outside of the connection plug to the other side splicing the positive wires together. Willa! the screen came to life. Happily cruising in Bras D’Or Lakes Nova Scotia Canada. Will return to Florida in October of course it’s a boat and the fingers shall remain crossed for good luck .