Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: George and Steph on December 21, 2016, 03:11:14 pm

Title: 2 Micron fuel filter...collateral damage?
Post by: George and Steph on December 21, 2016, 03:11:14 pm
During our return on our last trip we had a noticeable power drop in the 8.3.  Going through the fuel system prior to departure I picked up two fuel filters one for replacement and the second for a spare.  When I ran the numbers it turns out the tech who changed them had used a 2 micron WIX 33788 for the primary and a 14 micron for the on engine secondary.  I did not check the numbers when the work was done so I own it.  BUT I dont know these engines well enough to know what to check for that may have been damaged.  Anything I need to check for?

Title: Re: 2 Micron fuel filter...collateral damage?
Post by: wolfe10 on December 21, 2016, 03:18:19 pm
George,

No damage at all.  It is just that the primary fuel filter caught everything and clogged up.

I would replace with the 14 in the correct primary location and a new 2 in the correct secondary location.

Yes, you might be able to move the 14, but a leaking gasket would probably not make it worth the effort.
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: George and Steph on December 21, 2016, 03:22:25 pm
That is a relief...another lesson learned.
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: Pierce & Gaylie Stewart on December 21, 2016, 03:25:08 pm
George,

Diesel engines use the coarser of the filters for the primary filter with the secondary being the fine (2 micron) filter. The 14-16 micron primary filter rapidly turns into a much finer filter as it's the first filter to see diesel from the tank. The secondary filter traps the smaller particles that get though the primary filter. With the later common rail injection systems with their very high injection pressures, clean fuel is mandatory to avoid wear and damage to components with small clearances.

Good article here: Boating: When you have two fuel filters on your diesel engine, should they... (http://www.quora.com/Boating-When-you-have-two-fuel-filters-on-your-diesel-engine-should-they-both-have-the-same-micron-rating)

Pierce
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: Mike Leary (RIP) on December 21, 2016, 03:37:19 pm
Diesel engines use the coarser of the filters for the primary filter with the secondary being the fine (2 micron) filter. The 14-16 micron primary filter rapidly turns into a much finer filter as it's the first filter to see diesel from the tank. The secondary filter traps the smaller particles that get though the primary filter. With the later common rail injection systems with their very high injection pressures, clean fuel is mandatory to avoid wear and damage to components with small clearances.
On the DD engines, ('93 to '95) are the filters both close to each other in the stern compartment, curbside?
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: Pierce & Gaylie Stewart on December 21, 2016, 04:31:56 pm
Mike,

The primary filter is frame mounted at the rear on the passenger's side. Right behind that is the frame mounted hand pump. It generally gets little maintenance so replacement of the two "O" rings is a good idea. The bottom of the primary has a see through plastic cover with drain.

The secondary filter is on the driver's side mounted on the water pump housing just to the left of the pump.

The lift pump is engine driven and is pretty trouble free. To the right of the secondary filter.  It sends the fuel through the DDEC ECU to cool it before it goes into the cylinder heads.

The earlier 96" models with the rear (not side) radiator may have the secondary mounted in a different spot for access.

Pierce
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: George and Steph on December 21, 2016, 06:48:24 pm
Pierce thank you for the link to the article.  Interesting debate.
Title: Re: 2 Micron fuel filter...collateral damage?
Post by: kenhat on December 22, 2016, 01:46:47 am
Good article here: Boating: When you have two fuel filters on your diesel engine, should they... (http://www.quora.com/Boating-When-you-have-two-fuel-filters-on-your-diesel-engine-should-they-both-have-the-same-micron-rating)

Love this from the article:

Quote
Many modern high pressure common rail diesels and even old Detroit Diesel 2-cycle engines pump over 100 gallons of fuel per hour, per engine, so they do a very respectable job of polishing the fuel by themselves.)

see ya
ken