I have a 1998 U320 and I am looking for some advice. A little of the back story, my husband and I inherited the motorhome from my father in law about 15 years ago. about 5 years ago my husbands health became bad and he has since passed and because of this the motorhome has sat. I know this is the worst thing for them but it was unavoidable. I am now trying to get it running to sell but am having a fuel issue, I know its a fuel issue because we can fill the filter with diesel and it will run until the diesel is gone from the filter. I am almost confidant that it is the fuel line. Does anyone have a diagram of the fuel system for this coach? Thanks for any info.
I have never seen a diagram of the fuel system on our coaches from the factory but it does sound like you have tracked the problem down to plugged fuel lines. How much fuel is in the tank? Could you run a separate fuel line from a container to the filter then see what happens? Also I would change all fuel filters before trying anything else. Good luck!
I would see if you can inspect the fuel tank ( they have adaptors for Iphones and such). See if it has water in it
Pull the tank and replace the fuel lines from the tank to the rear. Replace all filters .. Refill tank and prime. It could be a number of things including Rats ate the lines, Algae in the lines/ tank, water in the fuel tank and so on.. Clean everything and start fresh with all new..
That would be me.. It will need done anyways and if you are selling its the right thing to do unless you want to basically give this away for cheap. ^.^d
You should have 2 fuel filters. Are you filling the large filter that is attached to the engine?
There is a pre-filter upstream of that filter.
The original pre-filter was problematic with not sealing and causing air to get into the fuel line. Mine is located in the rear on the passenger side in the same compartment as the 3 start batteries. It should have a clear filter canister with a water separator. There should also be a fuel pump attached to purge the fuel system of air after a filter change.
The previous owner of my coach bypassed this filter. I installed a new version that works great.
If you will tell us what city you live in or near, we may have a Forum member nearby. A "fuel" problem can be tricky to diagnose remotely because there can be, as noted above, multiple causes. Onsite evaluation by a experienced Foretravel coach owner could be very helpful in your situation.
See the member map linked below:
https://www.foreforums.com/index.php?action=GoogleMap
Thanks everyone for taking the time to respond. I am located in southern OK near Durant. We have found the secondary fuel filter and just to try and diagnose the problem we bypassed the filters all together. Yes we will put new ones back but we were thinking that they were the problem at first. If we had a diagram of the fuel system showing where all the lines are we were going to replace them all, I was trying to avoid hunting and maybe missing something. Its still a great coach low miles with no serious issues besides the fuel thing that really isn't a major issue if your not a girl lol. These are amazing motorhomes they age really well and stand up if taken care of.
A quick check to see if fuel lines may be bad is to look where the fuel line is pushed over the fitting on the filters. If cracks, assume AIR is getting in. This is on the suction side of the fuel system, so common to have air going in but no fuel coming out. Running new lines is not rocket science and there are a number of posts about owners who have done this. Just do a search here on the Foreforum.
Yes if you need to replace the fuel lines,you will have to pump out the fuel from the tank,then it will be obvious how the fuel lines are run. I use the old lines to pull the new lines through. If you do replace the engine fuel lines,also replace the lines to the generator and the aqua hot also.
You can check my post on the forum in 2019. I think it was when I replace my fuel lines. Luckily I had little fuel in the tank so I didn't have to pump any out. It's not a difficult job but it takes more than one person for a lot of it unless you're really good at this stuff. If you do do it, take lots of pictures so you know where everything goes back again. You'll have to clean the bays out so you can gain access to the fuel, hydraulic and power lines that run down the middle of them.
If you decide to take it to somebody to have them do the work make darn sure that the hose that they're going to use is the appropriate pose for continuous contact with diesel fuel. Just saying.
But at this point it could be other things too. Hopefully you won't have to replace the fuel lines, but if they're the original ones they're going to need it.
Although I don't know that that would make a huge drop in price to the right buyer. Depends on what other things it might need.
Good luck. Keep us up to date and let us know what you find out.
There is the mid south chapter rally in Durant in a couple of weeks, lots of people there that may help.
Keith