Fuel Filter Replacement

[SetTheBarlow]

Howdy! New to the forum and have a new to me 2009 Itasca Horizon 40TD with a Cummins 8.9ISL. I do my own maintenance on my my personal vehicles and want to do the same for the RV. I was currently trying to swap the fuel/water separator and secondary fuel filter but want to make sure I am not missing a step. When I loosened the fuel/water separator it never stopped leaking fuel from the top of the filter. It filled up half of my drain pan (never slowing down) before I tightened it back up. Is there something I need to do to break the vacuum from the tank first to stop the flow? I have opened the drain at the bottom of the filter first to drain some fuel out but that did not help. Thanks in advance for any newbie advice you can offer.

DB

[OMMM4747]

(1) Possibly a gravity fed filter aided by the fuel pump when the engine is running (filter placement is below that of the fuel tanks) or (2) The fuel line between the tank and filter continued to drain. Was your rig level? Maybe next time use the jacks to raise the back end -- fuel filter -- above the fuel tanks.

Since you say the fuel never stopped, you may be OK, but if it was about to stop and you installed the filter before it did, you may now have a substantial amount of air in the line. Ensure the filter is well primed before attempting to start the engine.

Good luck

[SetTheBarlow]

Flow never stopped and I never removed the old filter just tightened it back up to regroup. I think it is a gravity feed as you describe. It has hard lines going to the filter housing so clamps won't work to stop flow. Has a full tank of course so unless I get some other tips on where a shut off might be, I guess I will just swap as quick as I can. Coach is level, but the tank is full so don't know if being up in the rear would have helped much. If I make it through this time without too much of a diesel bath, I will do with with a quarter tank and rear up. Thanks much!

[wolfe10]

Two solutions:

Have the new filter ready to go IMMEDIATELY. With the appropriate catch bucket under it.



Better-- install a diesel compatible ball valve on the inlet to the primary fuel filter. Turn it off when changing filters OR as an excellent anti-theft device.


As already mentioned, with the filter removed, fuel level between the filter head and level of fuel in the tank will equalize. That means, if the level is higher in the tank it will run out. But, worse, if the level in the tank is lower, fuel will run back to the tank, leaving you with 30+ feet of AIR in the fuel line that will have to be purged.

[OMMM4747]

If there's no way to clamp the line, I'd open the fuel cap to relive pressure (if any) and raise the rear jacks to slow the downhill flow as much as possible. Prep the new filter -- install and lubricate the O-rings so you can quickly change it out. Despite the unfolding mess, try not to rush and cross thread!

BTW, my filter continued to drain for about a minute after the housing was empty. I don't know if it was the fuel line or the soaked filter draining, but it eventually stopped. You may want to give yours some time to do the same.

Although the YouTube video is for an engine different than yours (and mine), it proved helpful the first time I changed my filters. Unlike them however, I changed one filter at a time and ensured the engine started after each change. You can also try searching YouTube for your specific coach or engine.

Good luck

https://www.youtube.com/watch?v=i0Dw...llerIndustries

[SetTheBarlow]

I got it swapped and yes very easy to cross thread with trying to rush and get it back on. Ran fine after, now will move on to the other one. Thanks everyone!

[SetTheBarlow]

Well I spoke too soon, won't start now after replacing secondary filter. I put it on empty per the Cummins instructions and have used the key on lift pump priming procedure. I started to remove the filter and refill it myself, but it had fuel in it, although I don't believe it was completely full yet. I have done the key prime sequence at least 10 times since then. I can hear the pump run for several seconds, but the tone never changes like you would expect it to when it reaching full prime. Only thing I can think of is to remove secondary filter and see if it needs to be toped off with fuel. Again it ran several minutes on new fuel/water separator and old secondary filter so I was good up to that point. Open to suggestions!

[alank]

I went to a Cummins shop to change my filters and they just cycled the key (primer pump) and cranked the engine until it started. I'm sure they put the filters on dry and it takes quite a while that way. The primer pump won't remove the air between the filter and the injectors, only cranking the engine to operate the engine pump and injector pump until it starts will do that. Be sure your batteries are good because cranking the engine that much is hard on the batteries and starter. I'm glad I got to watch them do that; I never went back.

Starting the engine after the first change was a good move. That would remove any air from the first change. Fill the fuel filter as full as possible, remove the plug then screw it on. The very little amount of air in the very top of a full filter will cycle through rather quickly for a start. Installing an empty filter canister will give you the problem you describe.

Keep cycling the key and then cranking the engine.

[SafariBen]

I can't tell you the specific best way to bleed the air, but I'd try cycling it a couple times, then loosen the secondary filter, if you get air coming out under pressure, then tighten it and cycle a few more times and loosen again. If you get fuel then cycle a few more times, and then start cranking it a few seconds after every other pump cycle.

[koda59]

When changing fuel filters, my manual says to remove the filler cap to relieve the pressure. It also says to put filter on dry and continue to cycle key.

[OMMM4747]

My secondary filter came w/a plastic cap over the filter element opening. Do you recall if yours did and did you remove it? If you've done it all correctly just keep turning the key and giving it time to work. My lift pump runs for 30-secs which allows me time to walk to the engine and hear when the pump shuts off. From what you said, it appears you're not letting it run its full cycle ... Let the pump run until it shuts off.

In my case, for the secondary filter (installed dry), I cycled the pump 6x, cranked for 15 secs and the engine didn't turn over. I cycled the pump 2x and then it started right away.

Relax, you didn't break it. Retrace your steps and ensure you're giving enough complete cycles to refill your fuel lines and filter. You're probably very close. It'll start eventually. The learning curve is always steep the first time.

Good luck

[SetTheBarlow]

Finally got it going again this morning. What a relief! I don't know if letting it sit overnight helped, but I cycled the key a couple of times (like I did at least 20 times yesterday) and I could finally hear the pump have a change of pitch indicating it built pressure. A long crank after that and it fired up and ran for 20 minutes or so until I shut it down. The check engine light did come on, but I am assuming that was just to the irregular long crank/initial low fuel pressure. I am gong to give it another start and see if the light comes back on or if I need to hunt down the OBD connector to reset.

Thanks again for all the help and tips, I really appreciate it. Also in mid process of removing the basement air to replace with either a new unit or a refurbished used one from Shelburne RV. So far so good with that, everything is unhooked and ready to come out. I plan to get back on that in two weeks after a work trip and Steve can ship me a unit.

Other than that I plan to finish up the rest of the maintenance items on the coach and it should be good to go!

[NMBluept]

Both of my last 2 DP's have had what you call gravity feed or "pull" plumbed water/fuel separators. Here's the trick I use for the water/fuel separator. When preparing to change the filter do NOT top off the fuel tank - less than 1/2 tank is best. Select the highest fuel filler (DS on my coach), remove the cap and stick the hose from a vacuum cleaner in the filler, small shop vac works well. It should not be a tight fit, just tight enough to apply negative pressure to the fuel tank, but not suck fuel out. With vacuum running remove the water/fuel separator and change it out (mine has a cartridge to be changed so takes a bit). This reduces the fuel flow to barely a trickle or none at all.
When I attended Camp Freightliner I asked about this problem and Mike Cody laughed and said "you gotta be quick" - thanks for the helpful advice.
To fill or not fill is a great debate question. I think if you have access to clean diesel fuel then filling is the best way to go. My fine filter comes with a plug to allow filling the "dirty" part of the filter as per the provided instructions. I fill my filters as much as possible which reduces the cranking needed to get the engine started. Also change the filters separately (water separator first) and start the engine between.

Safe travels,

[ArtJoyce]

Filter is lower than fuel level in tank. Siphon, I aways try to do it when the tank is low, or with the back jacked up or on ramps, or all or the above.