Help with 2005 DT466e fuel system troubleshooting

[skoontz]

Hello all,
I am looking for a how to on how to troubleshoot my bus's fuel system. The short story is my bus died, and the mobile mechanic tells me that I need a new fuel pump. Thing is, I just replaced it a few months and 300ish miles ago with one I found online. The mechanic told me that I should replace it with one purchased the pump from the dealer, but I wonder if there is more going on.

Now, for the long version-

A couple months ago, I was driving the bus when I experienced a loss of power. In the span of 30 seconds, the bus went from normal operation, to losing power, to not being able to idle, and not even starting. I had it towed home, and had a mobile mechanic come out. He determined that the fuel lift pump was bad. I put a new one on, and the bus started again. However, I had problems with sometimes not having full power. It seemed hit or miss. I did still have air in the fuel system, and repriming the fuel system (using the hand pump and releasing air through the valve on top of the fuel filter housing) seemed to help. I thought maybe I had a very small leak in the fuel system, letting it suck up some air. I was still able to get it up to speed though, so I thought I was still working air out of the system.
On a recent trip, however, it kept getting worse. Towards the end, the Warn Engine light would come on sometimes under heavy load, and turn back off when I got to the flats. Finally, it sputtered and died when we pulled into the campsite (at least it waited until the campsite, and not the highway!). At this point, it would not restart. I had a different mobile mechanic out to look at it, and he was able to get the bus to start by pumping the hand pump. Based on that, I believe that he is right that the replacement fuel pump went bad. I am having the bus towed home (again - at least I have Good Sam now to help with this tow) and plan to work on it at my leisure. With all that said, could there be other things at play? Could something else cause the pump to fail? Basically, how can I troubleshoot my fuel system?

Also, any advice on a diagnostic system to talk to the computer?

[shortbus4x4]

Look on the left front of the engine intake manifold and you'll see a schrader valve that is on the high pressure fuel rail. Try pressing that in to let out any air in the system. Without a laptop and diag software that is about all I can suggest. I would call your local International dealer and see if they have a mobile tech come out and hook up to your bus. The factory diag software is NEDS.

[ewo1]

My friends bus did something similar but it happened at idle, not on the highway.
It turned out the “prime pump” went bad, was leaking air. Replaced the prime pump, running strong again.

Also, on a DT, Heui system, having low oil pressure might produce issues.
Make sure your oil is clean and oil pressure is good.

[skoontz]

Those are good points. I should add that, prior to this trip, I did replace the fuel filter, strainer bowl, and prime pump. I replaced the strainer bowl because I screwed up, and mistakenly overtightened it trying to remove it When I was messing with the fuel filter, I saw a lot of diesel come out of the prime pump, so I replaced that too. Of course, maybe it wasn't bad because the new one does the same thing. More

While I wasn't keeping a close eye on the oil pressure, I did just have the oil and coolant changed prior to our recent trip as preventative maintenance. It didn't seem to make a difference.

Honestly, the more I type, the more I convince myself that I did get a faulty lift pump

[ewo1]

Originally Posted by skoontz

Those are good points. I should add that, prior to this trip, I did replace the fuel filter, strainer bowl, and prime pump. I replaced the strainer bowl because I screwed up, and mistakenly overtightened it trying to remove it When I was messing with the fuel filter, I saw a lot of diesel come out of the prime pump, so I replaced that too. Of course, maybe it wasn't bad because the new one does the same thing. More

While I wasn't keeping a close eye on the oil pressure, I did just have the oil and coolant changed prior to our recent trip as preventative maintenance. It didn't seem to make a difference.

Honestly, the more I type, the more I convince myself that I did get a faulty lift pump

If it turns out just to be the lift pump, count $$$ your blessings.

I wonder if putting a pressure gauge after the lift pump, would that help in diagnosing your problem???

BTW, I posted a link to a dt466 service manual in this thread.

https://www.skoolie.net/forums/f37/d...ual-35598.html

Hope it helps out...

[ewo1]

Here is a diagnostic checklist...hope you find it useful.