02 Monaco Cayman ISB Series 8.9L 275 CM550

[Jim Andrews]

I was driving down the road happy go lucky when my MH just stopped on the highway. Pulled over and of course it wouldn't start. Mechanic came and changed the fuel filter and got it started for about 1 1/2 miles then stopped again. No lights prior, on error codes. It's now in the shop and "they" feel pretty good it's the fuel pump. $4k pump alone. I told them I filled it up back in October so the tank was full for the winter.  I drove it 2 to 3 times per month for a few miles to keep it lubricated.

After 325 miles or so, the engine stopped. I talked to them today and told them about the fuel and they said before they change the pump, they will check the fuel for algae and let me know the results.  If there is algae in the fuel, (didn't know that could happen), can they clean the fuel & pump without replacing it? Very expensive fix if that's what might have caused the problem.

[Luther Taylor]

Have them check the CAPS first before u change fuel pump. Do u have two fuel filters primary and secondary Change them both. If it’s a Cummings engine 

Edited September 13, 2020 by Luther Taylor

[jacwjames]

My coach came from Florida, I had no maintenance records or info on how long it sat.   Sometime after when I was changing fuel filters the primary filter was almost completely clogged by black slime.  No doubt if I hadn't changed fuel filters it would have eventually stopped the coach dead in it's tracks.

Since then I use a combination of Biobor (a biocide) which kills the algae and Startron (an enzyme) which breaks it down. 

Fuel filters could be your issue. 

Edited September 13, 2020 by jacwjames

[Jim Andrews]

19 minutes ago, Luther Taylor said:

Have them check the CAPS first before u change fuel pump. Do u have two fuel filters primary and secondary Change them both. If it’s a Cummings engine 

I will call and ask them to do that. Forgive my ignorance, what are CAPS? We did change both fuel filters first.

[Luther Taylor]

CAPS IS Cummins  Accumulator  Pump System. 
Have them pull the fault codes also. 
check crankshaft and cam shaft positioning sensors 

Edited September 14, 2020 by Luther Taylor

[Jim Andrews]

12 minutes ago, Luther Taylor said:

CAPS IS Cummins  Accumulator  Pump System. 
Have them pull the fault codes also. 
check crankshaft and cam shaft positioning sensors 

Thanks for explaining. The mechanics at Kenworth pulled the fault codes and nothing there relating to this problem. Had some high temp codes, but those came from when I was in the mountains 2 years ago.  I'm assuming the fuel pump and the CAPs are the same. That's is what they will replace after they check the fuel contamination.

[Luther Taylor]

Caps is separate from the fuel pump it sits on top of the pump And supplies the pump w fuel. 

[Pampero]

Sensor will throw a fault code.

You replaced both filters?

Bad fuel can clog the filter very quickly.

I will pull those filters again and see if they are clogged with algae, if they are then you will need to add a lot of anti gel and run the engine with no load until you can add more fuel to the tank

Edited September 14, 2020 by Pampero

[Jim Andrews]

14 minutes ago, Pampero said:

Sensor will throw a fault code.

You replaced both filters?

Bad fuel can clog the filter very quickly.

I will pull those filters again and see if they are clogged with algae, if they are then you will need to add a lot of anti gel and run the engine with no load until you can add more fuel to the tank

 

32 minutes ago, Luther Taylor said:

Caps is separate from the fuel pump it sits on top of the pump And supplies the pump w fuel. 

Gosh, I hope these mechanics would already know this stuff.  I am taking notes and will forward all of this info to them. Thanks.

[Bob Nodine]

There are two fuel filters, primary and secondary, it is imperative that they change both filters and that you carry spare filters just in case you encounter bad fuel.

 

[Dr4Film]

A new fuel pump (not the CAPS system) should only cost a few hundred dollars. I paid a Cummins shop less than $400 to change out mine. A new CAPS system is well over $4000 just for the part and another couple of thousand to install it as it is in a very difficult location to work on.

If you have really BAD fuel, changing fuel filters will only be a temporary cure as the new filters will clog up quickly starving your engine of fuel. If bad fuel, you either have to have the fuel in the tank "polished" or you can buy some products that will KILL all of the bacteria and microbes first then add another enzyme to eat all of the dead stuff up so the fuel filters can do their job. Once you have your fuel tank in good condition I would recommend using a mixture that I use in my Cummins ISC 350 which is a combination of Diesel Kleen and Biobir JF. I don't add it on every fuel tank fill but I will ALWAYS use it on the last tank fill before parking my coach for any long length of time especially when I am at my Florida winter residence.

[blahargoue]

For what it's worth, my 06 5.9 ISB in my Vacationer displayed the same symptoms.  The first time it was the lift pump.  The next year it was the fuel pump.  7 months later it was the turbo.  Two weeks later it became somebody else's problem!

By the way, it never threw a code.

Bruce LaHargoue

[Jim Andrews]

Here is an update for the reason my MH just stopped. I was out of fuel.......I know what y'all thinking, "Dumb ..s. It saved me a "potentially fuel pump" replacement and 6K. Now, I have happy feet!!!!  Well, don't be so quick to judge. I haven't driven my MH since last year and I was pretty sure I filled up the tank because I knew I was not going anywhere any time soon.

When I left, my fuel gauge said it was FULL (not almost, but past the F). When my MH stopped, my fuel gauge said I was just under 1/2 tank. I only traveled 300 miles and can go about 550 miles safely without the fuel light coming on. I don't ever let it go below 1/4 tank. Anyway, the problem was the "fuel gauge" and the tank "was" empty. Geeze.  This is only the 2nd time I every ran out of gas and my first one was in 1967 the year I graduated that's how I remembered it. Had a bunch of girls in the car celebrating graduation and it stopped right in town and had to be pushed to the side. Will "never" forget that one.

Thank all of you for your input and quick responses. That's what I like most about this site. So many knowledgable people. My sincere thanks again. Jim

[Dr4Film]

Been there and done that too just not the same way. My gauge works fine just not calibrated very well. So I got off at a location where there was supposed to be a Murphy's Gas Station according to the map but it was not there. So I had to cross over the overpass to the other side where I knew there was a station with diesel. The engine stopped on the way back to the main road. Once again on the way up the overpass. A third time on the way down the other side at the traffic light to turn into the fuel station. Then started it for most likely the last time once the light turned green and took the left. About 50 feet down the access road it quit again but I had enough momentum to roll into the station and up to the diesel pump. No power steering and very lucky indeed. I pumped over 100 gallons into a 128 gallon tank. Therefore there is a significant amount of fuel that is inaccessible. That will never happen again as I just stretched it just a bit too far looking for cheaper fuel using Gas Buddy. Now the tank gets filled every second day while traveling the usual 300 miles per day. If I don't fill the tank before stopping the second night I may not have the use of my generator and Aqua-Hot for hot water so no hot coffee in the morning nor a hot shower. That is not acceptable!

[Luther Taylor]

So glad that was all it was. 
Cheers. 

[Jim Andrews]

2 hours ago, Dr4Film said:

Been there and done that too just not the same way. My gauge works fine just not calibrated very well. So I got off at a location where there was supposed to be a Murphy's Gas Station according to the map but it was not there. So I had to cross over the overpass to the other side where I knew there was a station with diesel. The engine stopped on the way back to the main road. Once again on the way up the overpass. A third time on the way down the other side at the traffic light to turn into the fuel station. Then started it for most likely the last time once the light turned green and took the left. About 50 feet down the access road it quit again but I had enough momentum to roll into the station and up to the diesel pump. No power steering and very lucky indeed. I pumped over 100 gallons into a 128 gallon tank. Therefore there is a significant amount of fuel that is inaccessible. That will never happen again as I just stretched it just a bit too far looking for cheaper fuel using Gas Buddy. Now the tank gets filled every second day while traveling the usual 300 miles per day. If I don't fill the tank before stopping the second night I may not have the use of my generator and Aqua-Hot for hot water so no hot coffee in the morning nor a hot shower. That is not acceptable!

Thanks for the story. Interesting you had 28 gallons your unit didn't know was there. I would have thought the needle would have been way below the E line and would have still been going. Of course, I don't know what determines the tank has zero gallons or how that works. Diesels are new to me and I'm learning and I'm to old for these hard knocks. They hurt now!! lol

[Dr4Film]

Well I already knew the 28 gallons were there because I knew the capacity of the tank which is 128 gallons according to the specs of the coach in my manual. However, I think that the pickup tube for my Cummins engine is most likely not in the same location as other coaches. The same as the pickup tubes for the Aqua-Hot and generator are most likely not as low as others. So you have to get familiar with when you lose your fuel supply for each device. This was the first time it had happen to me with the engine but it won't happen again with the engine as I now know to never wait that long again to find fuel. With regards to the Aqua-Hot and generator I have lost their use at times during my travels but have gotten more familiar with where they will shut down due to lack of fuel so it's a leaning curve for sure.

Also, my fuel gauge is probably not the most accurate one because once it is full, I can drive many miles before the gauge starts to fall, so I have to take that into consideration too. Maybe one day when I get bored I will look into trying to calibrate a bit better but it isn't high on my priority list.

[dl_racing427]

12 hours ago, Jim Andrews said:

Here is an update for the reason my MH just stopped. I was out of fuel.......I know what y'all thinking, "Dumb ..s. It saved me a "potentially fuel pump" replacement and 6K. Now, I have happy feet!!!!  Well, don't be so quick to judge. I haven't driven my MH since last year and I was pretty sure I filled up the tank because I knew I was not going anywhere any time soon.

When I left, my fuel gauge said it was FULL (not almost, but past the F). When my MH stopped, my fuel gauge said I was just under 1/2 tank. I only traveled 300 miles and can go about 550 miles safely without the fuel light coming on. I don't ever let it go below 1/4 tank. Anyway, the problem was the "fuel gauge" and the tank "was" empty. Geeze.  This is only the 2nd time I every ran out of gas and my first one was in 1967 the year I graduated that's how I remembered it. Had a bunch of girls in the car celebrating graduation and it stopped right in town and had to be pushed to the side. Will "never" forget that one.

Thank all of you for your input and quick responses. That's what I like most about this site. So many knowledgable people. My sincere thanks again. Jim

LOL at the graduation story.   On the bright side, at least you had someone to push. 😉

[jacwjames]

I ran the generator until it quite, I drove it to a station and put 100 gallons of fuel in it.  I think I still showed ~1/4 tank,  I do not know how much fuel would have been left for the engine, would have been nice to know.  I know now have a Silverleaf VMSpc monitor and know how much fuel the engine is using and will fill up when I get down to about 1/3 of a tank. 

[dl_racing427]

It's a bit of work, but you could always carry 20 gallons or so in your trailer, drive until you run out, add enough to get to the nearest station, fill up and determine usable capacity.

[MBLSafariGazelle]

Thanks for letting us know about the cause. 
You probably do this or have heard it from others.....Follow your miles driven or planned as well as gen time. Helps to have a simple system to verify the gauge. If you have the Aladdin you can also follow your gallons burned for the main.

Be safe and have fun!

[Jim Andrews]

Thanks. To be honest, I would never have guessed the gas gauge would go out. I do typically watch my miles driven, thus knowing I only went 340 miles. I got fulled when apparently the gauge went bad when it was sitting, because it showed full. Who goes and gets fuel when the gauge shows it to be full. Me from now on for sure.

They are having trouble getting the part so I might go pick get my MH, drive it home and try to do the repair myself. I'm not sure if that means dropping the tank or what kind of job that would be to replace myself. Not excited to do that either, but I could if it's easily accessible. I haven't looked under the MH as it is in LR and I'm in Texas. Regardless, I'm going to pick it up this weekend and will have a full tank when I leave. lol

[Guest Ray Davis]

 On my Windsor I can look down into the fuel tank .  Un screw the cap and a flashlight will let me see the fuel level so if there is a doubt if the gauge is working properly I can get a pretty good idea if I need to stop for fuel right away .

Changing the fuel sender is not hard if you know where it is .   On my Windsor and I suppose your Cayman is the same , the door on the pass side that doesn't lift will actually lift if you crawl under the edge and unscrew 2 straps that hold it closed .   You can then lift the door , prop it up and the fuel sender is right there on top of the tank .  Several screws and wires then it will lift out .  Label the wires and take pictures . 

Edited September 18, 2020 by Ray Davis

[Luther Taylor]

Ironic that since you posted this my fuel gauge stopped working. 
it has power because when I turn ignition on the gauge jumps but reads fuel, assuming it must be a grounding problem. I can see the unit on top of the fuel tank thru the fuel door and the wires, checked all of them  and they are not loose.
I’m keeping track of mileage and refueling as needed. Hoping there is a fix without having to drop tank.  

[Guest Ray Davis]

Haven't heard of any Monacoers having to drop the tank

Edited September 18, 2020 by Ray Davis