Fuel Contamination Problem
Our 1999 Monaco Windsor has a Cummins ISC engine. The coach had sat for a year before we bought it. I had the coach serviced and checked out before driving it from Florida to New Jersey. As part of the service, all fuel filters were changed. The engine ran great until Virginia. While on I295 around Richmond, I was cruising along at 65 MPH. While rolling up a hill, the engine started to miss. After cresting the hill, everything was okay again. The next hill, same thing happened, only worse. I backed off to 55 MPH to see what would happen and everything ran good again, even going up and over the large bridge over the James River. Shortly after, the same miss came back. I even had the "Stop Engine" light on the dash come on. This worried me as I wasn't sure if this meant that I should immediately pull over and shut it off or not (did I tell you I'm a rookie when it comes to diesel engines?).
When that light came on, I pulled over to the shoulder and stopped. The light went out so I left the engine running. I called the dealer in Florida and asked the service tech about what I was experiencing and what if I could do any damage running the engine when the engine stop light came on. He told me not to worry about it, that that light was showing some sort of "conflict" and that I would be okay. He suggested finding a truck stop as a lot of times, you can find a diesel service center at the truck stop. I didn't know where the next truck stop was but figured since I was in the Richmond area, I could probably find someone in the area.
I ended up finding a Cummins Service Center. They determined that I had contamination in the fuel and showed me the fuel that came out of the primary filter (the one with the water separator on the bottom). There appeared to be a lot of black (dark) particles in the fuel. The Cummins Service Center ended up replacing the first two filters (three filter system) and gave me an additional primary filter to take with me in case the problem started up again.
I made it home without any further major incident. I did feel an occasional miss, but a lot less severe than the original problem. The biggest difference I noticed was less acceleration. Prior to the problem arising, when I pressed down on the accelerator, I had good acceleration. After the problem, I could still get up to 65 MPH but the acceleration was a lot slower, although steady.
Sorry this is so long.
What I'm asking is for suggestions on what I should do next. Should I get a sample of the fuel and send it off (where to?) to get analyzed. Do I simply bite the bullet and have the tank drained and dispose of the fuel, clean the tank and start fresh? Someone told me of a "bug" that feeds on diesel fuel and leaves its waste behind. Is this the black "stuff" I saw in the fuel? That same person told me of a Stanadyne product that will kill the "bug" and get rid of it if that is the problem. Another person suggested using Lucas diesel fuel additive.
I should also add that I was only getting about 6 MPG on the drive North. Does this seem low? I was expecting something in the neighborhood of 8 to 12 depending on any headwinds and terrain. Is this probably caused by the fuel which caused my other problem?
We have a trip to Yellowstone planned in two months and I would like to have all of this behind me before I leave. Thanks in advance for any and all suggestions.
Bryan and Lee - Retired Firefighter and Banker
Proud Parents of a US Marine
1999 Monaco Windsor 38' Suite Slide FD