Don8ch
Mississauga, Ontario
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In preparation for upcoming trip I obtained new fuel filter and fuel/water separator. Engine is Cummins ISB 340HP/660 Torque with post-2007 DPF.
1.) Fuel/water separator. I thought that I would drain the fuel from the bowl by opening the water drain until the filter emptied. Well fuel continued to drain into my tray until the quantity far exceeded the amount that the filter and bowl could possibly hold. I closed the valve and decided to restart the engine. Used the off/on proceedure about 6 times and started right up. Question: Will fuel continue to run out the entire time I have this filter off? My tray is only about 4 quarts and I'm concerned about overflowing it.
2.) While waiting for answer to 1. I decided to change the other (2 micron) filter. It was a real chore to get it loosened up but off and on, no problem. It also dripped fuel slowly the whole time the filter was off but no big deal. When I went to restart after the change I did the on/off sequence 6 times and tried to start. No start. Several more times - nope. I wasn't hitting the starter, just on for 20-30 seconds then off and repeat. Eventually (after 45 minutes of trying and cranking the starter for up to 15 seconds from time to time, it started. Whew! Are you supposed to hit the starter enough for a quick turn each time or just on/off?
Your help is appreciated.
Don
2009 Newmar Grand Star
3752 FRED
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wolfe10
Texas
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If level of fuel in the tank is above that of the primary filter, it WILL drain out the filter housing.
And, actually, that is preferable to it draining back to the tank where you would have to purge 29+ feet of air in the fuel line to get it started.
Choices:
Best-- install a ball valve on the fuel IN line of the primary fuel filter/water separator.
Change filter with lower fuel level in tank or aim coach nose down-- again see paragraph 2 above.
Brett Wolfe
1997 Safari Sahara 3540
EX: 1993 Foretravel 36' U-240
FMCA Forum: www.community.fmca.com/index
Diesel RV Club:http://www.dieselrvclub.org/
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Don8ch
Mississauga, Ontario
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Thanks Brett. That makes sense and based on the rate of flow I guess I will just have to move smartly to keep minimize the amount of fuel dropped during the change.
Brett's a Cat guy. I'm hoping the Cummins guys can help me with question 2. I'm told that it should self purge via the on/off method and wondered what I was doing wrong.
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Popsie
Livingston, TX, USA
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Joined: 04/04/2003
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When I change my fuel filters for my Cummins ISC engine, I always fill the new filters before putting them on - always starts right up.
I have a short pipe nipple that fits the threaded hole in the center of the filter. I put that in and then fill the filter (from a 2 gallon yellow diesel fuel can) through the outside holes until it's full. Then I remove the nipple and screw on the filter.
My fuel filter assembly includes a shut off valve, so of course I turn it off before, and back on again after, changing the filters.
Engine always has started right up.
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Don8ch
Mississauga, Ontario
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Thanks Popsie:
Apparently the filters for new Cummins engines are not supposed to be pre-filled and they are supposed to automatically prime with the on/off method. I'm wondering if I'm doing the on/off procedure incorrectly. i.e. do I have to bump the starter each cycle of the on/off?
Don
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Popsie
Livingston, TX, USA
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Don8ch wrote:Thanks Popsie:
Apparently the filters for new Cummins engines are not supposed to be pre-filled and they are supposed to automatically prime with the on/off method. I'm wondering if I'm doing the on/off procedure incorrectly. i.e. do I have to bump the starter each cycle of the on/off?
Don I always have pre-filled my fuel and oil filters, with never a problem. The point is that I keep any unfiltered fuel from getting into the center exit channel of the filter from which it could carry contaminants into the engine.
I'm pretty sure that the on/off procedure is to cycle the lift pump which brings the fuel from the tank to the first filter. The second filter with finer filter screening material only gets filled when the engine is turning over. So, in your case, I'd suggest turning the ignition on and off several times to prime the lift pump, (as in 30-45 seconds at a time for 3 or 4 times, then just crank the engine until it starts.
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mscamping
any place, USA
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I change both filters and put the new ones up dry.. Then turn the key on for about 20 to 25 seconds each time without engauging the starter,I do this 5 times, at the end of the 5th time I engauge the starter and it has always started.. You should not have to crank the engine that much, you will be replacing the starter at that rate.. I don't mess trying to drain them, just take them off, I let the fuel level go down, in the tank, below the level of the filters so you don't have fuel running out..
I would call or e-mail Cummins and ask them if this procedure has changed on the newer engines.. If it hasn't and you still have trouble, I would get a pipe niple to plug the large hole and refill in the little holes..
I think some guys do one filter at a time, but I usually get so dirty I wouldn't want to get in the moho to start it for the first filter.. Mike M..
* This post was
edited 10/08/11 05:50pm by mscamping *
2003 Holiday Rambler Neptune 36 PBD - ISB 300 Cummins- Allison MH2000 5 speed
2009 HHR w/Blue Ox Aventa II & SMI Stay-n-Play Duo
FMCA 331658 HRRVC 105155 Chapter - 57- Good Sam Life Member - Coach Net - 3/4 timers
Mike & Sharon
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farmer_boots
Weirsdale, Fl
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I have several diesels here on the farm and I always fill the filter with diesel and coat the seal with diesel prior to installing. The my tractors don't have electric fuel pumps so you have to hand pump them while venting the filter to ensure you have all the air out. The trucks on the other hand use electric fuel pumps. I turn the key on and leave it on until the computer turns the fuel pump off (that is cycle 1). Do that about 5 times and never had a problem (remember the filters are full of fuel).
On the motor home I do the same thing except I cant hear the fuel pump so I just leave the key on for a minute or so.
Sometimes in my haste I don't get all the air out and end up with air in the line at the injector pump. When that happens if you keep playing with it(trying to start the engine)the injector pump will vent the air back to the tank and things are ok after that. But that takes quite a bit of attempted starting. Most of the time I just bleed the injector pump to get rid of the air.
Is it possible you got air in the system when the filter was changed?
2006 Monaco Diplomat
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Don8ch
Mississauga, Ontario
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farmer_boots wrote:Is it possible you got air in the system when the filter was changed?
I'm thinking that must have occurred because it because it definately didn't prime itself as expected. This was my first experience changing the filter on the motorhome. Previously I had a Duramax pickup and 5th wheel. With the Dmax you had to manually prime with a thumb pump and bleed screw. That always worked fine; the automatic prime not so much.
Don
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wolfe10
Texas
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Don,
Again, a fuel shut off (just a ball valve) at the primary filter inlet will save you a lot of grief and keep fuel from siphoning from the system. It is quite likely that a high-mounted secondary filter opened to atmosphere allowed fuel to siphon back to the tank leaving you with a lot of air in the system.
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