4BY2 Engine Wiring diagram

C

captstu

Well-known member
Joined
Nov 10, 2014
Messages
862
Fluid Motion Model
C-248 C
Vessel Name
Shearwater IV (SOLD)
I need a wiring diagram for my 4BY2 engine electrical system.

The mechanics who have been working to correct the engine oil pressure fluctuation problem can't figure out what is wrong and don't have the necessary diagram or tools.

Happy to copy or even buy one if I can help them to the next step. Thanks /Stu
 
Stu:

In my 2012 R27 operation manual, given to us when we took deliver, has wiring diagrams in it. I have the manual in a file on my computer and as soon as I make this post I'll look it up and email it to you. I hope this helps.

Jim F
 
Jim,

My R-25 manual also has wiring diagrams for the boat. I think that diagram shows the engine as "engine wiring" and provides no detail.

I'm looking for the values - both digital and analog - for the engine oil pressure as it travels from the sensor thru the ECU and to the control panel. Mine shows no oil pressure and I think that is a minor disconnect someplace in the circuit.

If you have the engine wiring, I would be grateful.

Thank you. /Stu
 
Stu:

I've got one other manual that is the Yanmar engine parts manual. Not sure if it has what you're looking for but I'll email it to you anyway. If not give Kenny and Andrew a call. Did you get the first email I sent?

Jim F
 
I purchased the "Repair Manual" on line for $14.95. It was a company in Canada, they have hundreds and hundreds of manuals. It has a lot more detail then the owners manual. It's not "boat specific". Only the engine and components.
Google Yanmar (or whatever engine you have) and model number and $14.95. It will come up.
 
Pugtug, Thank you. I found the manual on line, but they will only give me a page at a time for a maximum of 6 pages or so. I can't find the company you used - but would be more than happy to send them the $15.

Do you have the manual number, I an order it as a part from Yanmar, I think. /Stu
 
Stu,
Are you doing the oil pressure bulletin? If so there needs to be a new ground run from the oil sensor unit to the paddle wheel connector lead, which is located in the wrapped up bundle of wires under the ECU box. It is marked paddle wheel. Also the ECU is supposed to be swapped out with an updated software. If this is another issue. I can take a look at the manual I have and it may have a wiring diagram. In any event did you throw an ohmmeter on the sensor terminals? As the pressure increases so should the resistance. I may also have those values in the book. Let me know and I will see what I can find.
 
I have been working with Yanmar for 2+ months and 2 dealers to do the oil pressure bulletin.

Marina One finally did it, I believe correctly, and it worked perfectly for about 4 hours.

Now there is no oil pressure, not just zero, but no indication at all.

Marina One and Yanmar have been working to see what isn't working - clearly not an internal engine problem since a mechanical gauge reads within specs.

The ground wire shift was restored to original - figuring fluctuation in pressure would teach us something, still no pressure.

They opened the wiring harness between the ECM and interface box to check the hidden ground splice - under Yanmar's direction. It was OK. But, they found an intentionally cut and taped ground wire in the harness - and are waiting for Yanmar to tell them if it should have been cut and tape at build or in a previous advisory.

This isn't the problem - it worked for four hours with the wire cut and taped - so I'm looking for manuals to find a hint because while Yanmar is cooperating fully, I've been without a boat for quite a while and am inpatient.
 
Stu, when you do get to the bottom of this problem please post back what the outcome was so we can all learn from what you've gone thru. Good luck.

Jim
 
Stu,
Send me your e-mail either here or in a PM. I have a detailed manual. I was looking through it there is a pin "V" on the X1 connector harness. This is the top grouping of wires on the box. The "V" is noted for the sensor and says "initial input for CAN hub. The whole electrical schematic may help. Hopefully I can send the whole manual. If I can't I will scan the electrical section and hopefully be able to send that.

Mike Rizzo
 
I e-mailed it and it looks like it went through. Electrical starts in section 12.

Good Luck and let us know how things progress.
 
Thank you all who sent e the various manuals for the ECM, interface and control head for my BY2.

Tomorrow, Yanmar techs are removing the interface module again to send it off to Yanmar again.

I'm still not sure it is the interface, but while it is out, I'll use the information you sent me to check the wiring to the oil pressure sensor.

I'm hoping for a happy ending fairly soon. Thanks again /Stu
 
In case anyone is interested in a "Repair Manual" for their engine. A ton of good info with plenty of details.
Go to WWW.MYGREENMANUALS.COM
If you use the code "MYGREENMANUALS" you get 25% off.
It's only $14.95 to begin with. It's a CD, not a hard copy. I just print out the pages I need or the chapter I need.
I think it's a great buy and a very handy tool to have.

They have many manuals available.
 
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