Volvo Penta KAD300 issue with engine data

[Targa35]

Have twin KAD300 engines with quite rare LCD displays (no analog dials installed except oil pressure). On port side engines at start I get the readings, rpm/temp/voltage/boost/…, but after some time of idle readings start to disappear and come back. When running at speed I get ”connection lost” on the LCD display and can’t see anything until back to idle when readings start again come and go. Both port side displays (upper and lower helm) does the same. Been swapping displays and tried disconnecting upper helm by unplugging from ms-unit with no success. Could it he faulty ECU or something else? Otherwise engine revs as before and gears work, no fault codes either.

 

[kashurst]

If the engines works OK and no fault codes it looks like a dodgy connection. I would start at the engine end and work my way through the loom/connections giving everything a good spray with contact cleaner. It may take a few goes and you may find some dodgy diy wiring along the way.

 

[Targa35]

Thanks! This issue started right after a lightning caused electrical surge which flicked our shore power fuse before isolation transformer which feeds the boat (lightning did not hit the boat but created a peak in the land grid we were connected to). Also, been studying the electrical wiring and information from ECU to display is transfered via J1708 gateway using voltage. These wires are in the same looms going to EDC and throttle potentiometer. So, there can be higher resistance in the wiring caused by bad connection. I will start to go through the connections next. And reason why upper helm LCD is showing the same problem is that info goes to main helm stadion LCD first and from there to second LCD. Just weird if it is only coincidence that this started after the fuse flicked.

 

[Sticky Fingers]

That new info sheds a light onto what might have happened; for the fuse to blow there must have been one hell of a surge - seems possible that your electronics are fried. As kashurst suggests you should check through; might also be worth swapping the displays between engines to see if the fault moves with the display or not which could help eliminate that possibility.

 

[Targa35]

Tried swapping and that did not help, same issue with other display and on stb side all LCD’s work. Confusing for me is could ECU fail only in a way that J1708 gateway is effected and otherwise all works in engine control.

 

[Sticky Fingers]

Sounds like the displays are ok and the feed is faulty or lost or damaged. Next step trace through the wiring I think.

 

[kashurst]

The fact that the J1708 gateway works at idle is strong evidence the ECU is working OK. The fact that the engines work OK indicates the ECU is OK
The lightening strike would affect the earth and 240v ac connection to the boat and every system on it. Nearby lightening strikes can cause all sorts of issues and create a lot of red herrings. You have two big lumps of metal in the water earthing your boat to the sea. Forget the lightening. I am assuming all your lights, radio, nav kit and battery chargers are all ok?

The engines both work OK
The displays albeit briefly and erratically work OK
If lightening had affected your boat they would not period.
You have a dodgy connection.

 

[Targa35]

Thank you again! And yes, plotters, battery chargers etc. work.

 

[Targa35]

Coming back to update this old thread just in case someone else experience similar issues. During winter 24/25 continued troubleshooting and checking connections in wiring but unfortunately was not able to fix the issue. In June I bit the bullet and purchased new ECU, installation took 15mins and everything started to work also, problems with upper helm station disappeared. My take on this is that both engine data to LCD displays and upper helm controls are using the J1708 gateway and the old ECU was not able to process data anymore whey frequency of data was higher, that’s why in idle data was visible and everything seemed to work (not an expert on this but maybe processor is just end of it’s life, ECU manufactured 2006).

 

[petem]

Coming back to update this old thread just in case someone else experience similar issues. During winter 24/25 continued troubleshooting and checking connections in wiring but unfortunately was not able to fix the issue. In June I bit the bullet and purchased new ECU, installation took 15mins and everything started to work also, problems with upper helm station disappeared. My take on this is that both engine data to LCD displays and upper helm controls are using the J1708 gateway and the old ECU was not able to process data anymore whey frequency of data was higher, that’s why in idle data was visible and everything seemed to work (not an expert on this but maybe processor is just end of it’s life, ECU manufactured 2006).

Glad you got it fixed. I'll have you old ECU if you don't want it!