2003 Monaco Dynasty power loss in engine

[Dale Snider]

I have loss of power …the turbo boos in a hard pull is only about 4 and going down the road on the flats turbo boost is 11-14.  At the top of a grade I seem to have no power but then it comes back.  I changed fuel filter and water seperator and the air filter is clean. Any one else have any issues like this?

[Dr4Film]

Possibly bad turbo or leaks in your CAC and or turbo path.

Edited May 12 by Dr4Film

[Dale Snider]

I also have some type of black stuff (maybe rubber) in the fuel seperstor

[Benjamin]

Tell me more about the black stuff, is it slimy or chunky?  "Algae" is a common fuel issue if the fuel isn't turned over like an RV sitting all winter.  You'll want to add some biocide to the tank, and carry spare filters.  Or flush the tank if it persists.  I'd try another water separator, don't have to throw the old one out, you can swish it around and dump the garbage out, AS LONG as you have a secondary filter.  If the engine is starved for fuel, it can't make boost.

[Dale Snider]

  Benjamin K

it is chunky like small pieces of rubber

[timaz996]

Just a guess, but that sounds like your fuel line is rotting.

[Dr4Film]

Normally, the very first thing to try is changing your fuel filters. They can clog up for a variety of reasons.

For an example, we drove from my brothers farm in Dansville NY to Cortland NY to visit cousins. Did NOT add any fuel to the tank. Parked the coach at the local campground. Then two days later broke camp to head to the Adirondacks. Left the campground but after driving not that far I had very little to no boost. Stopped, turned off the engine and restarted, all OK but then not far down the road the same situation. That's when I turned around and went back to the campground to unhook. I had to run to the local Napa store as I only had one of the two fuel filters on board. Got back to the coach and luckily right next door was a truck shop, drove over there to see if they would change out the filters for me. Had to wait an hour or so but once done I was back on the road with FULL boost. No idea why the filters were clogged but they were.

Always carry extra fuel filters as you never know WHEN you may need them.

If your tank is really messed up you may need a bunch of them or use some of the recommended products talked about on this site to remedy the situation. In severe cases you may even have to have the fuel in the tank professionally polished.

[jacwjames]

X2 on changing fuel filters as the first step and see if that solves the problem. 

The black pieces may be contamination due to algae.  When I had it the stuff was black slimy strings that almost completely clogged my primary filter.  But I have heard of harder black chunks.  

Since then I use both Biobor, which kills the algae, and Startron, which is an enzyme that breaks down the dead algae so it is consumed in the engine.  Never had another problem.

Not sure what engine you have, if it is the ISC series there is a potential problem with the lift/transfer pump that runs for ~30 seconds to prime the system.  The lift pump will start leaking but when it shuts off the CAPS injector pump has the potential to suck air which can eventually cause the injector pump to fail >>> $$$$$

My lift pump started to leak so a long term fix is to bypass and install a different lift pump.  I installed a FASS pump in 2021, which has 2 filters on it and cycles ~+85% of the fuel pumped back to tank, so while driving it will continually polish the fuel.  A big benefit to provide clean fuel to the engine.  I have a fuel pressure gauge installed on the secondary filter so I know how much pressure is at the injector pump, usually 16psi. 

[Benjamin]

I agree, the black chunks possibly came from the fuel line.  I'd remove the hose from the tank, if you can get to it.  Remove at the fuel separator and blow back toward the tank into a clean bucket, if you find more chunks of rubber there's your answer. 

I've heard fuel breakdown products described as fried chicken skin, that's the best way I can describe the harder stuff that fuel makes.  The slime is common also, neither should be a problem if you use many full tanks of fuel a year.  But with a hundred gallon tank, if you top it off before it goes below 1/2, then you end up with old fuel if you only go a few thousand miles a year.