ISC Primary vs Secondary Fuel Filter

[cbr046]

I too am headed down this meandering filter path.  I consider myself lucky, or Blessed, to have made it home Sunday night - ATC light & loss of power @ 20 lbs boost (manageable) that degraded to 10 lbs boost by the time I got home (400 mile trip). 

ISC 8.3L engine, 2003 HR Endeavor . . . . and I'm pretty new to the diesel world.  The coach sat idle most of 2019.  I've driven it 4k miles in the last 3 months.

PO installed a Donaldson P555001 fuel water separator ~ 4k miles ago.  According to Donaldson's site it's a 10 um filter where the OEM Fleetguard 1242 is a 20 um filter.  The Donaldson has a clear bowl that I could see some junk in.  Drained ~ 1 cup and the fuel is really dark (normal?) and if I hold it up to the light I can see some junk floating around in the bottom of it.  Not much junk, but obviously contaminated.  Right, that filter's gotta go. 

Q1 - is the Donaldson too much primary filter, filtering 10 um vs 20 um particles?

Q2 - Is it absolutely necessary to change the secondary filter (Fleetguard 1022 10 um) also?

Thanks in advance,

- bob

[Capt Mike]

I would advise you change both to the recommended filters. They suggest these filters for a reason. They are also cheap insurance against engine repairs. Just my humble opinion!

[ncsteve]

On my 04 8.3L I run (as did the previous owner who bought it new) the Fleetguard FF5488 and FS1003 filters.

I am relatively new as well, but always change both when I change them and carry spares.

as for the dark fuel, I would say your filters are clogged and need changed. The fuel should be clear.

in reguards to the micron ratings, someone with more knowledge will have to answer that.

[Cubflyer]

Mr Bob,

I'm new to these engines too, happen to have the same coach as you, '03 HR Endeavor, and like you, my unit sat for a while before I bought it this spring.  

I'm not new to engines in general.... and it sounds like my situation... Diesel fuel should not be black,  you need to deal with the fuel contamination (your diesel fuel is "growing micro organisms").

  My coach now has a FASS system. My hope is the FASS system "polishes" (cleans) the fuel and my current filters are not full of black when I change them in a few thousand miles.... When I removed the old filters, both to the main engine and my generator the fuel filters were black. My generator was barely starting and would shutdown under load.  Now it starts right up and purrs.... The main engine used to "pound" now it hums....  Clean fuel is a wonderful thing.

Ken 

[cbr046]

16 minutes ago, Cubflyer said:

Diesel fuel should not be black,  you need to deal with the fuel contamination (your diesel fuel is "growing micro organisms").

I've heard of that.  Is there a diesel conditioner that's preferred over others?  Amsoil?  BG? 

- bob

[Cubflyer]

Example of ugly black diesel fuel.... as for recommending Bio cleaners, I have to leave that to others....

I'm trying the "mechanical" cleaning with the FASS filter/pumping system, because it served two purposes, I needed a lift pump and I wanted "solid" fuel to be sent to my injector pump (so the injector pump was not trying to suck fuel from a fuel tank 30+ feet away thru two filters)

the engine primary and secondary filters were just as black as this photo of the gen filter fluid.

 

[Dr4Film]

Wow! Black diesel fuel, not good.

I use a combination of Diesel Kleen & BioBor-JF mixed with the Diesel Kleen at the maintenance level since my fuel is in good shape. You may want to consider the shock level for this fuel. There are other products (I don't remember the names) that some members will suggest plus there is one product that will eat up the dead microorganisms versus waiting for the filters to filter it all out of the tank.

Or you can do a search of this forum to find the names,

[vanwill52]

I've had the FASS system for quite a while now, and although I constructed and used a homemade 25 GPM "fuel polishing" system prior to installling it because of algae growing in the fuel, soon after installing the FASS system, I clogged two primary filters about 4000 miles apart.  I installed the FASS not because I had any issue of any kind.  I simply have the CAPS pump system and wanted it to have positive pressure at its inlet, rather than the Negative 5 PSI at which it normally runs.

Even though I thought my fuel was quite clean, constantly filtering it with the FASS system clogged new primary filters quickly.  That tells me it was not nearly as clean as I thought it was.  When the primary filters became clogged, it was not an issue, because I changed them before there was any fuel starvation.  I could do that because I installed a fuel pressure gage AT THE CAPS PUMP INLET (not between filters).  Long before the filter clogs to the point that you have an operational issue, the fuel pressure at the CAPS inlet will fall noticeably.  It is usually 15 PSI, even at WOT.  When it dropped to 10 PSI at WOT, I removed the primary filter and it showed significant contamination.  Same thing 4000 miles later.  The FASS system alone will not tell you that--you might still only know you have a problem when engine power is significantly reduced.  But with the fuel pressure gage AT THE CAPS PUMP INLET, you can change filters only when necessary.  I previously changed them annually.  Now I only change them when CAPS inlet pressure is reduced.  I have a 2 micron secondary filter.

I'm not suggesting a FASS system is your answer, although I think it will eventually "polish" all your fuel.  But a system as contaminated as yours may well cause you problems for a very long time until you have managed to rid it of most of the contaminants.  You could power on the FASS system without the engine running and constantly filter your fuel for days...the pump is Continuous Duty.  During that time, you would likely change primary filters several times.  And with the FASS system, changing filters is a breeze--no dependence on the multiple ON-OFF cycling of the ignition switch powering a wimpy lift pump.  Since it was not practical in my case to mount the FASS pump AT THE FUEL TANK, I added a valve at the inlet to the FASS pump which I close when changing filters.  That prevents the fuel from draining back into the tank and the FASS having to pull through 30 feet of air-filled hose

[Chuck B 2004 Windsor]

Before the newer diesel fuel was available, the older fuel had asphaltic ingredients in it.  Those ingredients coated the inside of your fuel tank.  Now that you are using the new blended diesel fuel, it is dissolving the coatings on the inside of your tank.  If I were you, I would find a good size yacht club that has fuel polishing equipment to clean your tank.  Bite the bullet and get your tank cleaned.  Then you can enjoy your travels down the Blvd. with no worries.  Chuck B 2004 Windsor 

[David K]

I have an ISC 350 in our 2003 Holiday Rambler Scepter.  I should preface my comments by saying I have never had contamination like the photos above.  When we originally bought the coach, I was new to a diesel powered motorhome.  After trial and error (i.e. changing filters on the side of the road), I developed the following system.  I use the Fleetguard filters specified by Cummins.  I add Diesel Kleen to the tank every time I buy diesel.  I change the primary and the secondary fuel filter at 5,000 miles.  (I will go up to 5,500 miles if I am not at a good place to change filters.)  Yes, I change them in campgrounds routinely.  (I have gotten pretty good at doing the filter change so I do not spill any diesel.  I have found I do not need to try and drain the primary filter water bowl before removing the filter.)  I carry a two gallon gas can with about one gallon of diesel fuel in it.  I fill up the new filters with clean diesel before installing them.  (I also put a thin coating of grease on the filter gaskets to aid in removal at the next change.)  The engine will start up immediately after changing the filters since they are full of fuel.  Since going to this method, I have not (knock on wood) had any issues with clogged filters.  I also change the fuel filter on my generator at every oil change.  I have made no other modifications to the fuel supply system to the coach or the generator.  We put about 20,000 miles a year on the coach.  

[ktloah]

I too had a tank load of "ALGAE". I couldn't go 100 miles till she clogged up...400 ISL. Shocked the tank with KILLEM. Bought many primary and secondary as well as aqua-hot filters...it eventually cleanup. Now I run a conditioner with each fill up. When my tank reads 1/2, I fill up. When it sits for any length of time, I add KILLEM. Good luck.