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Fuel Escaping on Air Purge

I have a feeling I'm not going to like the answer to this question but here goes...

I changed the RK12963 style primary fuel filter on our ISM.  I also pulled the 300200 plastic prefilter out to clean it but when I realized that it is basically a self contained unit I just put it back so that I can order a replacement.  I reassembled everything and pressed the air purge.  I neglected to press the schrader valve on the purge as the directions indicate - missed that.  Anyway, it pumped fuel and went through the cycle.  I read on some forum you have to press the air purge 2 or 3 times.  I pressed it a second time and shortly the pump started groaning and I could tell that pressure built up.  Shortly thereafter I saw diesel coming out from behind the slobber tube.  It was getting dark so I didn't investigate.  I did read about this engine having an automatic fuel system vent and assumed that was what it was.  But it did bug me why fuel would vent out if this common rail system has a fuel return.  I started the engine and the fuel leaking stopped and the engine ran well and started instantly.

Today I replaced the primary fuel filter during my first oil change as well.  I replaced it with what was there which is an FS1000 10 micron filter but I noticed in some other threads some people are using a 2 micron filter.  Should I be?  Replacement went easily and I again pressed the air purge button.  This time I didn't press the schrader valve because I thought it was pointless since the primary fuel filter was already full and fuel would probably spill all over me.  Again as soon as the primary filter filled up fuel started coming out. 

Trouble is the highest point I can see wetness is on the fuel line that runs from the primary fuel filter to the secondary.  Is this normal behavior or do I more than likely have a bad fuel line?  I can't really tell because the line is inside wire loom plastic but I'll dig in and figure it out if I get bad news here.

My fuel lines are cracking a bit.  I'm worried these lines are expensive.

Re: Fuel Escaping on Air Purge

Reply #1 –
Primary fuel filter (the first one the fuel gets to) should have a 10 or 30 micron filter element.

The secondary fuel filter should have a 2-5 micron filter element (depends on engine manufacturer's specs for you engine).

A 2 followed by a 2 is crazy-- clogging up the primary filter quickly and giving the secondary a "free ride".

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Fuel Escaping on Air Purge

Reply #2 –
I misspoke.  I think of the engine attached one as being the primary since it's the main filter that should be the finest micron. 

That one which is actually the secondary is 10 micron FS1000.  The primary is the FS19592 which goes on the RK12963 retrofit.  Should I use the FS1212 or is that for the 8.3 only?  I'm curious why they would put on the wrong filters.

Also anyone have any input about it spewing out fuel during the air purge?  Definite leak?

Re: Fuel Escaping on Air Purge

Reply #3 –
I have never had it spill out fuel when purging unless the valve was pressed but then again I press the valve.  I would say it was pumping fuel and it looked for the easiest place to go. The pump was stronger then the place it came out.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Fuel Escaping on Air Purge

Reply #4 –
Quote from: John S –
I have never had it spill out fuel when purging unless the valve was pressed but then again I press the valve.  I would say it was pumping fuel and it looked for the easiest place to go. The pump was stronger then the place it came out.

I think so.  I guess I'll start pulling back the insulation and identify the leak.  We are going to get a Transynd conversion done elsewhere so I could probbaly replace the fuel line while I'm at it.  It can't be a huge leak because we don't lose vacuum.

Re: Fuel Escaping on Air Purge

Reply #5 –
Quote from: wolfe10 –
Primary fuel filter (the first one the fuel gets to) should have a 10 or 30 micron filter element.

The secondary fuel filter should have a 2-5 micron filter element (depends on engine manufacturer's specs for you engine).

A 2 followed by a 2 is crazy-- clogging up the primary filter quickly and giving the secondary a "free ride".

Brett

So if I replace my Winn fuel filter system with a Parker/raycor 790/r30 in need an additional 2 micron filter after the new unit?

What was the original winn's  micron rating?

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Fuel Escaping on Air Purge

Reply #6 –
Bob,

As I understand things, the 790/r30 is the primary water separating fuel filter.  One then needs a secondary fuel filter which is mounted at the engine on my M11.

The 790/r30 filter performs the same function as the Racor R12T water separating fuel filter on the generator.

I replaced the problem prone electric powered Racor water separating filter with the Racor 490/r30 which has a manually hand operated priming pump which works very well and makes it simple, fewer things to leak and not turn on.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Fuel Escaping on Air Purge

Reply #7 –
Quote from: Rudy –
Bob,

As I understand things, the 790/r30 is the primary water separating fuel filter.  One then needs a secondary fuel filter which is mounted at the engine on my M11.

The 790/r30 filter performs the same function as the Racor R12T water separating fuel filter on the generator.

I replaced the problem prone electric powered Racor water separating filter with the Racor 490/r30 which has a manually hand operated priming pump which works very well and makes it simple, fewer things to leak and not turn on.

So my m11 has an engine mounted secondary already?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Fuel Escaping on Air Purge

Reply #8 –
Mine does.  You have to be under the coach on the passenger side to see it.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Fuel Escaping on Air Purge

Reply #9 –
For what it's worth we finally put our voluminous amount of stuff in cabinets and got the coach rolling today on a test trip.  First we rolled over to Walmart where I left it on high idle and filled all the tires.  The front and duals were 10psi low according to placard pressures.  The ride was a bit nasty on the way over but I was surprised to find the tag overinflated at 90psi.  I dropped the tag to 70psi and it rode smooth as glass.

No evidence of fuel leakage or starvation.  I put the hammer down getting on the highway and it ran fine.  No loss of vacuum overnight, started right up.  We're just going to roll with it until we have actual problems.

Re: Fuel Escaping on Air Purge

Reply #10 –
Quote from: piku –
For what it's worth we finally put our voluminous amount of stuff in cabinets and got the coach rolling today on a test trip.  First we rolled over to Walmart where I left it on high idle and filled all the tires.  The front and duals were 10psi low according to placard pressures.  The ride was a bit nasty on the way over but I was surprised to find the tag overinflated at 90psi.  I dropped the tag to 70psi and it rode smooth as glass.

No evidence of fuel leakage or starvation.  I put the hammer down getting on the highway and it ran fine.  No loss of vacuum overnight, started right up.  We're just going to roll with it until we have actual problems.

Weigh the axles to determine the correct tire pressure.
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Fuel Escaping on Air Purge

Reply #11 –
I would get a male to male brass fitting at lowes and carry it with you to bypass the Racor if you have to. 
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Fuel Escaping on Air Purge

Reply #13 –
Quote from: piku –
That's on the list but there are no scales nearby so I went with placard pressures

Slightly over inflated the tire steers very easy.  Under inflated the steering effort goes up noticeably in my experience

Bob
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4