Yanmar Electric Fuel Pump Wiring

[gorkem]

Hello All,

I have a 2011 model Yanmar 4JH5E 4 cylinder engine at 2500 hours. I realised that the wire supplying electric to the little fuel pump is broken. I want to replace the wire but I cannot follow the wire because it is packed with several wires together. Can you please help me to find where it is connected? I am planning replace the wire all the way from the origin.
Thanks for help.

Gorkem

 

[Ralph Johnstone]

I know exactly what you're dealing with. If you don't get any answers here, take a look at a Sperry wire tracker as shown below. I don't go tracing wires without this thing in hand. It does take a bit of practice to use it on minimum sensitivity. When you get the hang of it, it's worth it's weight in gold.

Depending on your electric fuel pump, if it is designed to fail open, and you have a full tank, you will not have any change in your engine operation.

 

[dlochner]

The wires are in the engine's wiring harness. This harness connects all the sensors and electric controls for the engine at the instrument panel.

It is unlikely that the wire is broken, more than likely the one of the terminal ends is a bit corroded and not making a good connection. First place to start is cleaning the terminals at the pump end as they are likely the easiest to access.

The wires are all color coded which makes the job easier. The positive wire likely ends up new the ignition switch, so when the switch is on, the pump is energized and pumping. The negative end is tied to a bunch of other negative from other devices.

Find a copy of the shop manual, there will be a schematic in it. There may also be one in the owner's manual. Get a magnifying glass the print will be really small.

Good Luck, no one raves about the quality of Yanmar wiring harnesses.

 

[SycloneDriver]

It's also possible that the circuit runs through an oil pressure switch. If the oil pressure is lost the fuel pump will stop running, it's a safety feature. Good luck tracing that wire by hand, I have done it but it can be very frustrating.

 

[gorkem]

Thanks for your replies. I have cut the wire until I find a good looking part. Still I can not read proper voltage. I will check connection sockets. The terminals were already burned as you can see below. I have checked the fuel pump with a external battery and It sounds normally...

 

[gorkem]

 

[jssailem]

Yes... That was a fire hazard waiting to ignite...