Fuel pump not activating and 10Amp fuse blowing

[ColinF]

Hi guys.
I'm new to this Argo 8x8 750HDI Kohler engine.
It stopped running a couple of weeks ago with a failed electric fuel pump.

I replaced the pump and inline filter and it ran again but within a day dropped onto 1 cylinder.
I've checked the spark plugs and ignition circuit and the blink diagnostic says its #52 which is electrical short or break to the fuel injector for #2 cylinder.
I also found the 10 amp fuse beside the ecu had blown.
I think the injector code was just the connector at the injector not fully installed but the 10 amp fuse has blown again and the new pump wont activate.No fuel no start.
I get continuity from the injector connector to the relay block but don't know what I should get with the other wire
I tested the relay as OK per the manual.

Why would this 10amp fuse be blowing?

Any helpful suggestions would be welcome.Cheers Colin.

[Grizzly10]

You said it had a failed pump , now your having other problems. Carefully go back to the scene of the crime. CAREFULLY, Thoroughly check the fuel pump wiring. May be touching metal somewhere causing a short. Often times it’s the basics that get us. Just check. Also look and see what the rating is on the pump are they identical? Maybe the new one needs to be fused larger. Just a guess. Give it a shot, with the attitude of I’m gonna fix this thing. It works. Don’t let it win. ��)

[plott hound]

my hdi dropped one cylinder when i first got it,drove me nuts trying to figure out the issue.turned out to be a corroded and loose spade connector at the rear coil.got it cleaned and tightened up,put a dab of dielectric grease on it and been trouble free now for years.

[ColinF]

Thanks for both replies.I checked coil connections, they're good. It does seem there's something shorting in the fuel pump circuit that I have yet to discover without digging deeper.I've printed out the wiring diagram and will see if I can follow the circuit.But todays day 1 of 2022 and the Argo can wait.Happy new year to you all.

[ARGOJIM]

Try shaking the wires behind the seat, could be the feed wires are chafed near the parking brake handle.

[bakedalaskan]

Disconnect the battery to let the computer reset then see if the pump starts. I know this sounds simple but it worked for me after an hour of troubleshooting in the field. My friend said "Just do me a favor and disconnect the battery. Just for grins!" That worked. This will not fix your blown fuse issue and I did not have a blown fuse but the pump would not start. I had been dealing with a misfire and a check engine light for several hours when it finally quit running. That is when I noticed my pump was not pressurizing the system. The computer had locked it out somehow. It took two more battery disconnects to get back to the truck. It turned out to be a bad computer and bad O2 sensor. (Both of which had been under water 4 months earlier.)

[ColinF]

Well its running but I'm still not sure whats going on to cause the stoppage.
I disconnected the battery and replaced the fuse and checked for short circuits as best I could.Found nothing out of sorts.

I then disconnected the new pump and reconnected it directly to the battery.Positive to positive terminal neg to neg and the pump wouldn't run.
Then after 5 or 6 attempts the pump sprang into life.
I reconnected it back to its usual wiring and everything started right up and seems to be running fine.I've stopped and started it several times and have no idea whats going on.
Brand new factory electric pump with less than 10 minutes on it.
What do you thinks happening? There's no longer an error code light on the dash.
Faulty pump?

I'm pleased its running again but disconcerted it may happen again if I don't understand the cause.

[ColinF]

There's more and some questions.The new fuel pump failed within a week and I've since fitted another new Walbro pump.I flushed out the tank and replaced fuel lines and installed an extra filter before the pump in case it was something in the fuel that caused the pump failure.
The pump did its self bleeding cycle for a minute or so when I turned the ignition on and then it started right up.I notice the fuel pump is running all the time even at idle.Is that normal?For some reason I thought the pump would switch on and off especially at idle.

So questions.What could have caused the failures? And does the pump run continuously when the engine is running or could the pressure relief valve be faulty?

Thanks.