NMEA 2000/Electrical consistent headaches

rondds said:
You can set up a voltmeter on the terminals and get a reading. Then, holding the voltmeter in place, have someone crank the engine and compare to the "unloaded" reading. You should have a voltmeter on your breaker panel too. You can look at that when they're cranking. Do you know how old the batts are? They might still have the month/year stickers in place. ie: E8 would mean May of 2008 (5th month of 2008).

This was the panel on my previous boat. The two lowest meters are DC VOLTS (to the left) and DC AMPS (to the right). The switch just to the left of the VOLT meter lets you select port or starboard. Yours probably looks different (this boat was a 1989) but pretty much all SRs have this setup in the panel.

I only had 3 on my 340DB. If you do find the stbd bank to be week, replace both (they are likely connected in parallel) at the same time, even if one is ok and the other is bad. Sounds like your batts are in a difficult place to access. Typical of boats!

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Yes, I have a meter for both AC and DC. Unfortunately, I can't switch between port and starboard like you could. I'll check all the info you posted and get back to you. Even if I switch the batteries, and it doesn't spike and the MFD stays on during crank, I may still have my issue. I did do an emergency start, and the MFD didn't cut off.. it dimmed though. I'm guessing that the DSM300 may be giving me problems.
 
You have any idea how old they are?
 
Unfortunately, buying those batteries did not fix my issue. After doing more troubleshooting, I've realized that whenever I disconnect the long blue cable from the port engine, the depth shows up on the DSM 150 and fixes my problem. So I guess the port engine is shorting everything out. Everything works perfectly when I disconnect it from the engine or the J box.
 
What does the blue cable go to? Justin removed and reinstalled the engine.....yes?

I think he would be more than willing to help here...
 
That's the CAN bus. You can try replacing that cable for that engine and see if it solves the problem. Long shot but...

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rondds said:
That's the CAN bus. You can try replacing that cable for that engine and see if it solves the problem. Long shot but...

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That's exactly how I have it set up. I don't think it's the cord. I used the same cord from the starboard engine (that works) and it still posed the same problem. The cord itself is still working, sending engine data. I have my raymarine DSM 300 hooked to the raymarine e120, that's hooked into the NMEA 2000 network that's also hooked into my maretron DSM 150.
 
Is your NMEA2000 Backbone grounded? Bad contacts where it's getting voltage? Sorry - I'm grasping at straws.
 
rondds said:
Is your NMEA2000 Backbone grounded? Bad contacts where it's getting voltage? Sorry - I'm grasping at straws.
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I thought about that, simply moved the backbone and the DSM 300 to different connectors on the "black power hub" and still no luck. I figured if it was grounded bad, I wouldn't receive any data at all. Starboard starts fine with no issues and shows depth on the MARETRON DSM 150. The port engine is the only one that causes issues.
 
One last thing I can think of..

You have 2 engines. Each engine is supposed to be "coded" with port/starboard ID numbers. That coding is done before the boat leaves the factory. If you boat thinks it has 2 "starboard" engines with same ID number - there is trouble ahead.

The only way to get that set is to get a Merc guy out with a computer and check if the engines have been coded correct at the installation time. Under normal circumstances it would not be an issue but once you connect something "across" both engines like a SystemView/VesselView or N2k Gateway - the issues will show up since the two engines is talking "on the same lane" at the same time.
 
kaz911 said:
One last thing I can think of..

You have 2 engines. Each engine is supposed to be "coded" with port/starboard ID numbers. That coding is done before the boat leaves the factory. If you boat thinks it has 2 "starboard" engines with same ID number - there is trouble ahead.

The only way to get that set is to get a Merc guy out with a computer and check if the engines have been coded correct at the installation time. Under normal circumstances it would not be an issue but once you connect something "across" both engines like a SystemView/VesselView or N2k Gateway - the issues will show up since the two engines is talking "on the same lane" at the same time.
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Yup, I had that completed by justin, a local dealer. I have engine info for each engine coming in, Rpms, coolant temp, all that working for each engine.
 
Grabbing at straws as well........ For testing purposes, is it possible to power everything from an alternate source? I'm thinking a completely separate battery sitting in the ER or the cockpit and then fire up the engines. If it still does the same thing then I would think voltage drop is not the issue.
 
dpmulvey said:
Grabbing at straws as well........ For testing purposes, is it possible to power everything from an alternate source? I'm thinking a completely separate battery sitting in the ER or the cockpit and then fire up the engines. If it still does the same thing then I would think voltage drop is not the issue.
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I'm order the bluesea ACR, installing that, then running a direct line to my generator battery. After that's all said and done, hopefully my issue will be resolved. I spoke with Mercruiser yesterday, and Raymarine this morning.. all are saying to push both the MFD and DSM 300 to an alternate source. I'll probably do that with my NMEA2000 backbone as well.
 
Another straw here and showing my age..... Is the cable only able to pass data one way and perhaps your reversed it when you switched it to the other engine?
 
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