Community Forums

H. Miller · 09-20-2014, 07:06 AM

CONFUSION! The Cummins engine has a fuel filter installed by Cummins on the curb side of the engine. Some Monaco owners manuals do not mention this filter (you need the Cummins engine manual).
Monaco installed a second filter in the rear/road side (behind the dash a/c condenser). They call it a fuel/water separator, not "filter".

Bob&AnnaMari · 09-20-2014, 04:22 PM

Quote:

Originally Posted by blkcloud

after installing the lift pump, we took it on a test drive of about 20 miles.. ten miles each way.. on the 19.8th mile it quit dead in the road and we had to pull it the rest of the way with a tractor back to the shop.. if the lift pump didnt fill the filter when it first started.. would it have gone nearly 20 miles befoe it conked out?

Nope. You are right. Not the lift pump.

DieselTech39 · 09-20-2014, 04:36 PM

If it's a FL chassis then you could have a Racor filter some where. Many have found it tied up with the electrical wiring in the frame rail.

Here's what it looks like:

deSanford · 09-20-2014, 09:26 PM

Our little RV has 5 fuel filters. One on the Cummins engine passenger side, one on driver's side rear fuel and water separator, two on the lift pump......one for fuel and one more for water and it also removes the "AIR" from the fuel after the fuel gets sloshed around in the tank. The 5th is an inline diesel fuel filter going to the Onan 8K diesel generator. deSanford

Papa_Jim · 09-20-2014, 10:21 PM

Your 2000 Monaco Diplomat is built on the Roadmaster Chassis. 8 outboard air bags, with side radiator. There are two fuel filters. The secondary filter will be on the engine, probably somewhere just above the starter. Take caution when changing this filter. There is the large square O-ring that seals the filter canister, but take notice that there is also a small square O-ring that fits on the nipple that the filter screws onto. That small O-ring is supposed to be supplied with the new filter, but sometimes it is not. If that small O-ring is missing, or damaged, the fuel filter will not fill properly, nor will the fuel flow properly to the engine. Check that.

Your coach has a primary fuel filter, but I do not know where it is. It probably is a Racor filter. Those filter units have been known to draw air at the filter seals and connections. That could cause a myriad of problems, one of which can be the inability to fill the secondary fuel filter because of air being drawn into the system. I would replace that filter and see if things improve.

Hope this doesn't confuse things.

Jim

vanbuskirk · 09-20-2014, 11:51 PM

We encountered the same issue. Finally found the primary tucked way up I'm the chases totally obscured by wires. It was only because a mechanic went inch by inch with his fingers following the fuel line and finally located a fitting of which then after cutting all of the wire tires they located the primary filter. We spent over a thousand dollars trying to analyze and correct our problem and it turned out to be a 16 dollar part that hadn't been changed since it left the factory in 2008. We were told that after the chases is delivered to the MH manufacturer that they relocate them to meet their floor plan needs so not all of them on the same models are at the same place.

None the less we now keep a filter and a separator on hand at all times.

blkcloud · 09-23-2014, 07:22 PM

Yesterday I took the fuel lines loose and hooked up 2 clear lines to my lift pump, then ran the hoses into a cut off 2 1/2 gallon jug of diesel fuel.. fired her up and took off down the road.. perfect.. no issues... so I crawled back under and tried to move the transmission with my head.,,, it doesnt move... now I got a goose egg on my head.. back to the story.. I started feeling the fuel line and followed it amoung the mass of other lines all tie wrapped together.. finally it went away from the motor on the passenger side to the drivers side behind the rear wheel where my hydraulic unit is.. right to what I thought was a hydraulic filter.. I mean.. I have looked at it many times and it has hydraulic type lines running in and out of it and its not a foot away from my hydraulic unit.. but it is my diesel water seperator.. no wires hooked into the bottom of it either like some thought it should have.. I dont know if this will cure my problem but I sure hope it does.. the whole top of the filter was stopped up with algae.. will put a new one on tomorrow.. I have some tank treatment but will start a new post to find out what is best.. thanks for your help!

Skip426 · 09-23-2014, 07:33 PM

Grab a couple of extra filters , your going to need them.
That's one ugly mass on that filter. You may need to have the tank flushed.

Bob&AnnaMari · 09-23-2014, 07:49 PM

Yes, it may take a few filters before things are back in shape. But, the good news is you found the filter/separator and can work towards a solution now. Just finding all the parts on these things is a real challenge. (Maybe your attempt to move the transmission around helped clear the cobwebs and get you on the right track. At least that is what I try to convince myself was the reason I bashed my head -- or knuckles on something.

)

I look forward to hearing how you get this all resolved.
Bob

DieselTech39 · 09-23-2014, 08:10 PM

Glad you found the most likely cause of your problem. Here's a couple links that might help you with saving the fuel in your tank. JMHO

Biodiesel Biocide Bacteria Treatment - Utah Biodiesel Supply

http://www.powerservice.com/bk/

I agree with Skip.....2 or 3 extra filters.

walt2137 · 09-24-2014, 06:43 AM

Quote:

Originally Posted by blkcloud

Yesterday I took the fuel lines loose and hooked up 2 clear lines to my lift pump, then ran the hoses into a cut off 2 1/2 gallon jug of diesel fuel.. fired her up and took off down the road.. perfect.. no issues... so I crawled back under and tried to move the transmission with my head.,,, it doesnt move... now I got a goose egg on my head.. back to the story.. I started feeling the fuel line and followed it amoung the mass of other lines all tie wrapped together.. finally it went away from the motor on the passenger side to the drivers side behind the rear wheel where my hydraulic unit is.. right to what I thought was a hydraulic filter.. I mean.. I have looked at it many times and it has hydraulic type lines running in and out of it and its not a foot away from my hydraulic unit.. but it is my diesel water seperator.. no wires hooked into the bottom of it either like some thought it should have.. I dont know if this will cure my problem but I sure hope it does.. the whole top of the filter was stopped up with algae.. will put a new one on tomorrow.. I have some tank treatment but will start a new post to find out what is best.. thanks for your help!

That hydraulic unit is your RVI jacks and it has no filter,and you do have a hyd filter in that compartment for your steering that probably needs changing. I think there was a number of post about both filters.

blkcloud · 09-24-2014, 02:39 PM

I'll look in there for it and try to change it also.. thanks!!

walt2137 · 09-24-2014, 02:55 PM

The hyd resivor should be toward the front and you will have to remove the top to fish the sock like filter out its a 10 Micronesia filter and the original was a Nelson 83213D or a Napa 1487 but double check the micron .