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Tom_Barb's avatar
Tom_Barb
Explorer
Jun 04, 2015

Continued dirty fuel problems.

As many readers here know, we have been having dirty fuel problems. We bought our Newmar in 2009, it had sat 9 years in dry storage I had only 8700 miles on it. We worked our way thru. the wake up period with new hoses belts, and tires, and were really happy with the coach. 2010 we were returning from a trip to NY, and the coach started to loose power, and would quit, we would wait 15-20 minutes and it would start and run but at a lower speed than normal. I changed fuel filters and it returned to normal, I changed filters 2 more times from N.M. to Wa. all were contaminated with a black debris looking like soot from a chimney. It's a had particulate matter and fells like black sand.

I was totally convinced that we had loaded a bad / dirty fuel.

Once at home, I drained all fuel, removed the fuel tank, hoses, filters, and associated units flushed and cleaned them, replaced all the equipment. and it has run great until this month. we now have 41k on the cummins. we find the whole fuel system is contaminated again.
Same stuff, same symptoms, and same Fault codes of low fuel pressure.

I have now replaced both fuel filters, re-set the fault codes and the coach runs great again.

But where in the world is this stuff coming from?

I believe the Cummins 8.3 ISC 350 horse is producing the carbon, and returning it to the tank, which is clogging the filters. I have asked Cummins for assistance but have not heard from them yet.
Class A

19 Replies

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  • wolfe10's avatar
    wolfe10
    Explorer
    Jun 04, 2015
    Could be the fuel lines breaking down. Pull one where you have access and look carefully at the inside.
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Jun 04, 2015
    Son of Norway wrote:
    What you describe is like the carbon in a vapor canister.

    Miles


    Exactly, but we don't have any of them.

    The fuel I get from the filter bowls looks like I washed out the tail pipe with it. or what you'd find at the bottom of and old oil pan. it is absolutely black.
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Jun 04, 2015
    rgatijnet1 wrote:
    I have restored several old Classic vehicles and old fuel tanks can be a problem. Most fuel tanks are coated/plated to prevent rust but that only lasts for so long. Once rust starts to form in a fuel tank, just flushing it out WILL NOT solve the problem. "Rusticles" will continue to form in the tank, even if it is full, unless it is flushed and the interior is coated/sealed with one of the numerous products on the market for this purpose. These "rusticles" are very fine particles and they will clog most filters and can get past most filters that are not designed for fuel injected vehicles.


    Lab tests on this says it is carbon, not iron oxide. (that is what rust is)
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Jun 04, 2015
    I have restored several old Classic vehicles and old fuel tanks can be a problem. Most fuel tanks are coated/plated to prevent rust but that only lasts for so long. Once rust starts to form in a fuel tank, just flushing it out WILL NOT solve the problem. "Rusticles" will continue to form in the tank, even if it is full, unless it is flushed and the interior is coated/sealed with one of the numerous products on the market for this purpose. These "rusticles" are very fine particles and they will clog most filters and can get past most filters that are not designed for fuel injected vehicles.
  • Bigdog's avatar
    Bigdog
    Explorer
    Jun 04, 2015
    I drove a 1978 GMC Buffalo to Mexico several years ago for a church group and it had been sitting for several years with a 1/2 tank of fuel. I checked it out, drove it to a mech to have it checked further and got fuel on the way back to park it. Loaded the kids and gear and headed out. Got fuel in Redding and added some fuel system cleaner and headed out the next morning. After stopping at Cottonwillow rest area,it started up fine,but as soon as we started to move, it stopped. We got it towed in to Bakersfield at 4 AM and got a mechanic from Valley out on a Sunday AM to fix it. It turns out that there was the type of algae that grows in diesel plugging the fuel line and both filters. He changed thefilters and blew out the fuel line from both ends and told me to hot fuel it for the next couple of tanks. Gave us a couple of extra filters and I hot fueled it there in Bakersfield and just before we went into Mexico and didn't have a bit of trouble.
    He also told me that you always want to park it with a full tank of fuel to stay away from that problem.
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Jun 04, 2015
    path1 wrote:
    You run any type of biocide?


    I do, but this not I repeat this is not Algae. Algae is a slime that clogged filters, you need water to grow Algae, there has never been any water show up in my filters, this is hard particulate carbon that feels like sand. I've had under a microscope, it is carbon particles. Not Algae.

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