Why is this plus cable from the house battery bank connected to the engine (VP MD2040

[hzcruiser]

Originally Posted by Tornadosailing

I took a closer look at your pictures. It looks to me that the wire in question at the fuel filter and engine block are black with a red stripe. I don't see that wire going to your battery. Are you 100% sure it's the same wire?

Also, replace your fuel hoses before you have to start fighting an engine dying issue.

Well picked up, I would've missed those cracks in the fuel hose, too. It also looks as if two red/black wires are coming out of the fuel filter grounding lug?

[pcmm]

Originally Posted by jonase

Unfortunately it is connected to the positive on the house/equipment batteries. I just did a documentation and labeling of the battery banks and found this odd cable.

It's hard to see on the photo but it is connected to the positive of the house battery bank.

Starting to think that maybe you are right but it has been incorrectly reconnected due to the color. Boat is new to me so don't know how long this has been wrong if it is a bonding cable...

https://imgur.com/a/Qmo4iQo

https://imgur.com/a/gSOrL9y

II think you need to retrace that wire. The wire on the the filter is a red/black combo (2 wires actually) but your pic of the battery does not show the same wire... It's likely connected to the engine as a ground.

[jonase]

Thanks for all the comments. I retraced the cable today and you are allcorrect, it's a ground cable. The ground cable is running to the main switch board.

The cable on the house battery bank that I mistook for this cable was the alternator sensor conductor cable (that is supposed to be yellow). This cable is red as well as the ground cable in question.

[jonase]

Since I all you have been so helpful. I will try another question…

Today when I was retracing the cable I aslo checked how the fuel hoses were running from the tank to the engine in preparations of replacing the fuel hoses. Thanks @Tornadosailing for pointing this out, it was easer to see on the picture then in real life ;-)

From the tank there are two fule hoses running to the engine. One of them is connected to the fuel pre-filter before connecting to the engine. But the other fuel hose is running directly for the engine back to the tank. Checked the manual but could not find any information about this hose. What is this hose used for.

https://imgur.com/a/TbVPxAW

PS: Sorry for the noob questions. Ask me about sailing, sails, blocks rigging etc and I know it all (almost). But engine and electricsystems are not my expertise…

[DougR]

The return fuel line that you are referring to is commonly called an injector bleed off line. It's purpose is two fold:
- all injectors have moving parts inside of them and this line takes a small percentage of the fuel which is pumped to the injectors and returns it to the tank while passing it over the injectors internal moving parts. This lubricates the parts and cools them.
- secondly, on your engine there is a metal pipe that connects between the fuel input fitting of the high pressure fuel pump up to the return line connected to the injectors. So, fuel comes from the secondary fuel filter and is fed to the injection pump, and on its way into the injection pump it goes into the banjo fitting on the top of the pump, where the metal pipe is also connected. The metal pipe is held in place with a small banjo bolt and that banjo bolt has a very small bleed hole in it. This bleed hole is big enough to allow air to escape the fuel stream, but small enough to prevent much fuel from escaping. Thus any air that makes its way into the fuel feed system is diverted back to the tank along with the injector bleed off fuel.

Hopefully this prevents air in the fuel problems and makes it easier to bleed the system after filter changes, etc.

DougR

[hellosailor]

jonase-
May I suggest there is an elephant in the room?
The boat is new to you and you're first exploring, which is good. But apparently a PO did some unconventional wiring. Perhaps they needed a ground wire and red was the only thing they had so they figured, wtf, use the wire you have. That suggests the PO may ave done other "wft" things that may confound or mislead others. And, if that is a ground wire but you're not familiar enough with electrics to spot it...

It might be a good idea to settle down over a weekend with a good book on basic boat electricals. Slower--but ultimately better--than calling in a pro to check over the electrical system, looking for other possible issues.

That's not to say everything must be "done to code", just that if you starting with one questionable piece of work, it makes sense to check everything over, document it, and go forward knowing you'll have a solid foundation.

Boats find enough ways to demand attention when everything is done right. When you find extra large sneakers and a used fright wig...check carefully for Bozo.

[Stu Jackson]

Originally Posted by hellosailor

>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

It might be a good idea to settle down over a weekend with a good book on basic boat electricals. Slower--but ultimately better--than calling in a pro to check over the electrical system, looking for other possible issues.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

You could start here:


Electrical Systems 101

[jonase]

Originally Posted by hellosailor

jonase-
May I suggest there is an elephant in the room?
The boat is new to you and you're first exploring, which is good. But apparently a PO did some unconventional wiring. Perhaps they needed a ground wire and red was the only thing they had so they figured, wtf, use the wire you have. That suggests the PO may ave done other "wft" things that may confound or mislead others. And, if that is a ground wire but you're not familiar enough with electrics to spot it...

It might be a good idea to settle down over a weekend with a good book on basic boat electricals. Slower--but ultimately better--than calling in a pro to check over the electrical system, looking for other possible issues.

That's not to say everything must be "done to code", just that if you starting with one questionable piece of work, it makes sense to check everything over, document it, and go forward knowing you'll have a solid foundation.

Boats find enough ways to demand attention when everything is done right. When you find extra large sneakers and a used fright wig...check carefully for Bozo.

What you describe is kind of what I am doing. The only difference is that I use Internet instead of a book. The two boat electrics book that I have is a bit outdated and don’t cover the topics that I am wondering about. Thanks @Stu Jackson your links to the 101’s are great!

Started with documenting all the wiring to the start and house battery bank. After the documentation I also labeled all the cables. There were one cable especially that was a wtf cable. The other red ground cables I could figure out. The wtf cable was the one I posted in the forum and it ended up being me fooled by two identical cables that were bundled together with several other cables.

If anyone is interested the final battery banks documentation is here…
https://imgur.com/a/jkN9jfw

Know that I have to replace the fuel hoses but am also considering replacing the house battery bank with Lithium in the long run. Planning to rewire the positive side and also rewire the house battery bank.

Planned rewire
https://imgur.com/a/wHtlUWn