I'm working on a 1995 U320 with the CAT 3176 engine. The coach has the old Winn filter system on it. There are 2 small electric fuel pumps that prime the Winn filter. Before I determine what I'm going to do with the system I have one thing I need to understand.
Question:
1. When the ignition key is turned on will the fuel pumps run continuously to help supply the engine with fuel? (That's what my coach is doing). Was it wired from the factory that way or was this system modified to use the fuel pumps as booster pumps with the key on?
2. I thought the pumps were for priming the fuel filters only when you push the button on the controller? (Correct or incorrect)
3. If I change to a new filter system, do I need to have the 2 additional pumps to help supply fuel to the engine or will the CAT engine mechanically pull the fuel from the tank without assistance.
Thanks
I'be never heard of a U320 with a CAT 3176 engine. Does anyone know how many were produced?
Very few. In 1995 there were three engines used: first were DD 6V92, then Caterpillar 3176, then Cummins M11.
Is there a mechanical fuel lift pump on the engine?
The mech lift pump should be about 9 inches above the starter.
Do both electric pumps, pump in the same direction?
Are both electric pumps on the same fuel line?
Is one electric pump on the fuel return line?
If not, one of the pumps would be the engines fuel priming pump. It should not run continuously.
The second pump may have replaced the mech pump, if so, it should run continuously.
Good luck...
Tim
Thanks Tim, I did find a mechanical fuel pump.
Both pumps are running in the same direction.
Both pumps pull from the same line from the tank. Run through the Winn filter system, then to the mechanical CAT pump.
I was hoping someone else had the CAT 3176 and see if they had the same setup. Factory installed? I seem to have no power to pumps with the Winn control box buttons, just runs with key in on position.
Maybe changed, and wired to run with key on because old fuel lines??? Speculating???
Another key question:
Should the engine be able to run with full power without the electric pumps, using the mechanical pump?
Does anyone know the details? I've never seen a DD 6V92 in a U320; I've seen a CAT 3176 in a 1995 U300 but never in a U320 before; and I'm aware of one DD Series 60 in one U320. I and many others have the Cummins M11 in our U320s. Certainly would like to see a detailed listing!
David,
I may have mis-spoken.
It may be only the 1995 U300 that used the three different engines.
From what I have seen:
1995 U320 with 3 different engine combinations.
DD series 60, CAT 3176, Cummins M11
Never seen a DD 6v92 in a U320, just in the U300.
Anyone have the answer:
Should the engine be able to run with full power without the electric pumps, using the mechanical pump?
I speak with no information on your particular coach
But on my 2001 U320 with the Winn filter there is a internal pump used to purge fuel only. If activated while the engine is running it too will run thru its timed cycle and shut off. My coach has no other pumps and the fuel injection pump must of been spec for the particular needs. It does draw a vacuum during operation even with new filters. I do have a fuel filter minder that records the vacuum between the secondary filter and does not show if the primary filter is being plugged. Just the screen and secondary. I'm assuming if your Winn pump does not have the same purge pump then they added a set of continuous duty pumps rather than a more expensive single pump, but I'm guessing at best. With experience with other diesels I prefer to have a electric pump at the tank to keep positive pressure on the pump and prevents air introduction do to leaks. Air will damage pumps do to cavitation regardless of how small it may be. Then multiply by happening its entire service life. Your fuel screen is 100 micron and just stops the big stuff. On mine i can easily view the clean screen and fuel passing thru it. Yours was last dated in 2016 and looks contaminated to me. FWI it take four o-rings. Prior post cover it well.
IMO i will be converting mine to a FASS lift pump that separates all air intrapped fuel and returns to the tank. This will result in having a positive head pressure for the injection pump and any leaks will be from pressure and be visually detectable as a fuel leak, not being drawn into the fuel line and remaining unknown. Someone added the electric pumps possible to patch a problem. Again just speculating.
Scott
Lift Pump for 01 U320 (https://www.foreforums.com/index.php?topic=41496.msg413591#msg413591)
I would assume that a restriction anywhere "upstream" of the fuel gauge/minder would add to the vacuum/restriction on the gauge.
If you have followed my dilemma: fuel starvation every 50 to 100 miles puts me on the side of the road from very low turbo pressure. I have the original Winn system for my year of coach. The fuel/air little panel above the engine lately now fails to activate for "fuel purge'', but does run the "air purge" pump system quite well.
Question, do you think this could be the cause of my loss of fuel - presumably from air entering the lines? I'm thinking there is only one pump in the Winn system and I have occasional loss of fuel for some other reason.
Jim
2002 U320 42' M-11 450 hp
You may have seen my earlier posts regarding the Winn system. Mine was problematic—particularly in colder weather. I replaced it with a Parker 790R30 and have experienced zero problems since then. I recommend you do the same.
I appreciate the answers. As this subject continues on I'm thinking this was factory. That big over kill bracket and same vintage fuel lines.
Am I giving credit to a factory installation with 2 electric fuel pumps like a 1994-1995 FASS pump system, positive pressure to aid the mechanical pump?
Scott then you mentioned your Winn system had a internal pump, is that so or does your system have the external electric pumps. Does anyone have external pumps? I guess I'm trying to figure if this was built this way for the Winn system or not. Maybe one pump was for the Winn system purge and the second one for positive fuel pressure?
Definitely seems unique CAT 3176, Primus heat, mini airbags for the generator mounts, there is other unique things I have never seen on a Foretravel before on this coach. Must of done a lot of custom things back then for customers. I will post some other things below.
This coach has what I call mini jacks instead of using the airbags for leveling.
Had a tube that pulled the toilet gas (smell) via a hose that had a suction fan in the wet bay below that exited under the coach.
The last thing I was going to leave for people to guess, but decided just to put what it seems to be for. This pull cable next to the driver allows you to adjust the front airbag ride height on the fly.
I had the Winn system in my 1995 U320 with Cummins M11. The Winn system had one internal pump used only for initial priming. The replacement Parker 790R30 also has a single internal pump used only for initial priming. I wonder if you could check to see what pump (or pumps) is (are) on trucks the have the CAT 3176 engine?
Also, what is the unit number of the U320 you are dealing with? A picture of the data plate would be interesting!
Just as David and many others have done I replaced my WINN system with the Parker 790R system.
I also have the Primus heating system installed on my 95 U320, very few coaches made with that system installed.
Coach #4558 U320C SE
[/quote]
That's an interesting number. My build number is 4726, built in February 1995. If 5455 is actually your build number then it would have been built in something like 1997 or even later.
I suspect the number 5455 is from the VIN and not from the Model Number. The "unit number" will be the fourth through the seventh characters in the Model Number, such as mine is G954726 . . . .
Yes. My minder is "Tee'd" into the manual Schroeder vent. Only reads vacuum between developed between sand prior to secondary filer and primary filter. I have no indications if the primary filter is restricted to the pump. Eventually will address.
Scott
I have and do believe you have a fuel starvation issue complicated by a air leak. The fuel water drain function on the back of the engine has a sensor seeking a ground as I recall. I added a test ground to it so i can fake water in the fuel that opens the drain solenoid and drains into that evaporation bag attached to it. My bag has been removed and a drain line to the bottom of the coach added. I operate during oil change to verify function and shutting off. The one pump in the Winn is only to purge air from the filters. Does not run continuously. One my coach
Scott
I too have considered the Parker 790R30 but it does not have a continuous duty pump. Only a purge pump. The engine driven pump is adequate and the Winn if you maintain correctly works fine, however if there is a air leak it will be hidden from you on both systems. I would rather have the leak identified so it can be repaired rather than hidden reducing the fuel rail pressures available to the fuel injection system. Yes both will work, I'm not disputing that. I also could be completely wrong. For the same amount of money spent ill have a purge pump, lift pump and air removal system. Not to mention a fuel polishing system. Positive pressure to the injection pump eliminated any cavitation and associated problems. IMO
Scott
Sorry DJ, I was off one set of numbers off. I believe this is the one of or the first U320 made.
I was told the owners were friends with the Fore family and helped with a lot of the design features of the U320 coach. I have old pictures of them testing the primus and front windshield tests for the defrost system
Coach 4558
No external pumps yet. FASS system down the road for sure. The Winn has worked fine for me once i figured out you needed four orings for the screen and replaced the old screen. I just prefer some head pressure on the injection pump and verified no leaks.
I must say you have a unique coach, usually those things in life find there way too my house. Glad it found you first. The mini rams and the vent system all sound like patches for other problems. Very cool coach for sure and quite interesting one off coach.
Scott
That makes a lot of sense. It's fascinating to learn about the very unique coaches from that time period!
Here is the "Vent A Bowl" instructions. I also have some unique floor plan ideas they where considering. The one marked "Special" actually exists I went to Las Vegas to buy it but had some issues I didn't like that were not disclosed. I wish they made more.