Coach will not start & a diesel leak

Topic: Coach will not start & a diesel leak (Read 1177 times) previous topic - next topic

Coach will not start & a diesel leak

April 01, 2020, 02:48:33 pm

We're in Colorado at about 4100 ft elevation and are having a tough time getting the coach to start.

Yesterday morning the engine wouldn't start, it would sputter occasionally but would not fire. We tried several times without luck so I bled the fuel system before and after the injection pump and the engine started for a second or two but that was it. We let it sit for about 10 minutes, tried again and the engine started. It ran rough for a bit but then started running like normal.

This morning we tried again and the engine started right up. But after about 30 seconds the engine died and is not wanting to start again.

This morning I discovered that we have a diesel leak at the tank and don't know if that could have something to do with our starting problem. Maybe the split is preventing the fuel tank from holding pressure or letting air into the fuel? As for the leak, I think the fuel might be splashing around while we're driving and leaking from a split in the filler neck but am going to do some more searching.

I feel like the engine issue is a fuel issue but am not sure how to test for it.

Is it possible that the split in the filler neck, if that is the source of the leak, could prevent the engine from starting?

Thanks in advance,
Tyler

Re: Coach will not start & a diesel leak

Reply #1 – April 01, 2020, 02:52:50 pm

No, the split in the filler neck will have no effect on fuel to the engine.

But, VERY IMPORTANT: You need to immediately get all the fuel cleaned up off the FG floor, or it will leak down into the basement structure and dissolve the insulation and give the basement a permanent diesel smell. Pay particular attention to the area around the screened area.

For the no start, check for cracks in the fuel line letting air in-- a good place to start looking is where the fuel line comes into the primary fuel filter.

Re: Coach will not start & a diesel leak

Reply #2 – April 01, 2020, 02:57:47 pm

Do what Brett said and how old are the fuel filters,could they need a change.

Re: Coach will not start & a diesel leak

Reply #3 – April 01, 2020, 03:12:48 pm

General information, my U320 also has a minute leak at the filler neck..its not a problem as far as a mess goes, But displays terrible aluminum welding...Maybe a good idea to check for leaks on all coaches, as Brett is right. And Diesel fuel stinks for a long time....
Safe Travels
Dave

Re: Coach will not start & a diesel leak

Reply #4 – April 01, 2020, 03:44:14 pm

Quote from: John44 – April 01, 2020, 02:57:47 pm

Do what Brett said and how old are the fuel filters,could they need a change.

I changed both of the fuel filters about a week ago and everything was running great until yesterday. I tried to bleed the system at the injectors again but could not get any fuel to spray out of 4 of them.

Re: Coach will not start & a diesel leak

Reply #5 – April 01, 2020, 03:46:54 pm

Sure sounds like an air leak between tank and lift pump (the suction side of the fuel system).

If it were a leak on the engine side of the lift pump you would have a fuel leak (fuel OUT instead of air IN).

Re: Coach will not start & a diesel leak

Reply #6 – April 01, 2020, 04:01:03 pm

Quote from: wolfe10 – April 01, 2020, 03:46:54 pm

Sure sounds like an air leak between tank and lift pump (the suction side of the fuel system).

If it were a leak on the engine side of the lift pump you would have a fuel leak (fuel OUT instead of air IN).

How can I check for a leak on the suction side of the line? I've looked at the fittings and don't see any signs of a leak.

Re: Coach will not start & a diesel leak

Reply #7 – April 01, 2020, 04:07:28 pm

I would be up for trying to change out the fuel lines but I'm not sure how to get the correct length of hose made with the threaded fittings on both sides. Are there some type of push-on fittings I can use if we get the correct size fuel line?

What are those fittings called?

Re: Coach will not start & a diesel leak

Reply #8 – April 01, 2020, 04:28:54 pm

If, after the engine has run for awhile after changing the fuel filters (i.e. all air bled out of the system) you are still bleeding air from the system, it HAS to be getting in on the suction side of the system. A need to re-prime is a symptom of this.

So either the fuel line from tank to primary filter, primary filter itself or line from primary filter to lift pump.

Lots of posts here on the Foreforum on changing fuel lines.

Re: Coach will not start & a diesel leak

Reply #9 – April 01, 2020, 04:32:44 pm

Quote from: The Soft Boulders – April 01, 2020, 04:07:28 pm

I would be up for trying to change out the fuel lines but I'm not sure how to get the correct length of hose made with the threaded fittings on both sides. Are there some type of push-on fittings I can use if we get the correct size fuel line?

What are those fittings called?

The hose behind the one in your picture has the push on fitting. The Aeroquip fitting on the outer hose is a pita to reuse. Match up the one on the inside and read, read, read before attempting to change the hoses yourself. There are many posts on how different members did the job including pictures.

Re: Coach will not start & a diesel leak

Reply #10 – April 01, 2020, 04:42:20 pm

I've been reading trough posts but haven't found much yet. I did see somewhere that the GV's had less issue with fuel lines than some of the other models with rubber fuel lines. Our fuel lines are a braided material and not rubber. The generator fuel lines are rubber and show visible cracking where as the coach lines don't. Either way If I can figure out the correct fuel line sizes and the type of hose end fittings I need the installation appears to be pretty straightforward.

Re: Coach will not start & a diesel leak

Reply #11 – April 01, 2020, 04:49:47 pm

If this problem just started soon after changing the fuel filters, probably worth rechecking that they are the correct parts and that you have the correct number and style of gasket. Easy to leave on old o ring on the filter housing and install a fuel filter with an additional one.

Re: Coach will not start & a diesel leak

Reply #12 – April 01, 2020, 05:29:53 pm

What is the fuel filter number that you guys with the C8.3 are using? The part number that Cummins gave me and that I ordered was FF42000. They said that it was an updated part # but It didn't look right from the beginning. I just removed it to take a picture of what I'm talking about.

The mating surface that the filter screws to is flush all the way across but the inner gasket on this new filter is recessed. It doesn't seem right to me as I can't see how it's supposed to seal.

Re: Coach will not start & a diesel leak

Reply #13 – April 01, 2020, 05:57:57 pm

I have rechecked the fuel filter and water separator and both appear to be good. I Imagine that the fuel filter is the correct one as the pt# the MOT used (FF5052) does cross reference to FF42000. Probably wishful thinking but worth a try.

Re: Coach will not start & a diesel leak

Reply #14 – April 01, 2020, 06:04:29 pm

Quote from: The Soft Boulders – April 01, 2020, 03:44:14 pm

I changed both of the fuel filters about a week ago and everything was running great until yesterday. I tried to bleed the system at the injectors again but could not get any fuel to spray out of 4 of them.

Captain Obvious here, but . . . Bingo?
If you changed out both of the fuel filters, that's the first place to check for a leak.

You wrote: " It doesn't seem right to me as I can't see how it's supposed to seal."

If you can't see how it's supposed to seal, then it doesn't seal. Sorry.

The odds are that you missed something when you changed the fuel filters, but I don't have eyes on as do you.

FWIW, Remembering that you somehow need to run the new fuel line where the old one is, Take the old line(s) to a shop that can make you new ones. Better to let them fight with those fittings.

In the meantime, do whatever it is you do while the sun sets.

Re: Coach will not start & a diesel leak

Reply #15 – April 01, 2020, 06:06:01 pm

Tyler, your filter looks like it needs the square O Ring if the mating surface is flat as you mention. There should have been one in filter packaging if it is needed.
JohnH

Re: Coach will not start & a diesel leak

Reply #16 – April 01, 2020, 06:12:28 pm

Did you remove and replace the small center gasket on the filter housing? Should have been supplied with the new filter.

Re: Coach will not start & a diesel leak

Reply #17 – April 01, 2020, 07:03:33 pm

Do you have the chassis mounted hand fuel pump? It's mounted on the frame just inside the engine door on the right hand side on our 1993 U300. Really easy to prime the filters but may need to check the hand pump O rings if you have a problem with the pump. About $0.10 each at NAPA.

But first, I would buy a degreaser from a auto parts store or Walmart. Think 2 gallons is about $10. Clean the area then then use a auto spray wash wand to get rid of ALL of the diesel. You don't want even a trace left as it can really smell and like Brett says, you don't even want it in your basement. Once the tank and compartment are spotless, you can check for a fuel leak on the tank or at a hose. Sudden diesel leaks along with not starting go to together like Mutt and Jeff. Check fuel lines at the top of the tank with a bright flashlight.

And, while I'm thinking about it, the tank mounting flange in the photo looks as if it has been damaged, either from pulling the tank or from something from below. They are not supposed to look like that.

Pierce

Re: Coach will not start & a diesel leak

Reply #18 – April 01, 2020, 07:34:42 pm

Quote from: Doug W. – April 01, 2020, 06:12:28 pm

Did you remove and replace the small center gasket on the filter housing? Should have been supplied with the new filter.

On the filter that I have the inner o-ring is built in. I went to Napa and got a Wix fuel filter to compare. On both filters the inner o-ring is recessed but the Fleetguard filter o-ring was quite a bit more recessed. I filled the new filter with fuel and primed it then tried starting it. The engine turned over for about 10 seconds then fired up and idled normally. I don't want to say that the new filter fixed anything until I try starting it tomorrow but it's a good sign.

We found the source of the diesel leak and it's not in a good spot. The fuel tank itself is leaking along one of the welded seams. There is no visible crack in the weld but fuel is seeping out in at least two spots along the seam.

Anyone ever had that happen and or know how to fix it?

Re: Coach will not start & a diesel leak

Reply #19 – April 01, 2020, 07:41:35 pm

This works on fuel tanks without draining. Has fixed 2 crane fuel tank leaks.

https://www.napaonline.com/en/p/NCB8267S?cid=social_blog_072017_JB_weld_tank

Re: Coach will not start & a diesel leak

Reply #20 – April 01, 2020, 07:44:43 pm

Quote from: craneman – April 01, 2020, 07:41:35 pm

This works on fuel tanks without draining. Has fixed 2 crane fuel tank leaks.

Epoxy Adhesive JB Steelstik 2 oz NCB 8267S | Buy Online - NAPA Auto Parts

Excellent!

Re: Coach will not start & a diesel leak

Reply #21 – April 01, 2020, 09:15:41 pm

Quote from: The Soft Boulders – April 01, 2020, 07:34:42 pm

We found the source of the diesel leak and it's not in a good spot. The fuel tank itself is leaking along one of the welded seams. There is no visible crack in the weld but fuel is seeping out in at least two spots along the seam.

Anyone ever had that happen and or know how to fix it?

I would pull the fuel tank and have it rewelded. You're going to be living with that tank for a long time.

Re: Coach will not start & a diesel leak

Reply #22 – April 02, 2020, 09:41:03 am

Until fixed, be sure to catch 100% of the diesel so it doesn't get down in the basement structure.

If nothing else and it is just seeping, tape paper towel "diapers" just above floor level to catch it.

If really leaking, see if you can use tape and aluminum foil or other to form a channel to divert the fuel to a container.

Re: Coach will not start & a diesel leak

Reply #23 – April 02, 2020, 10:39:24 am

But the fuel leak in the side of the tank is not going to cause the engine not to start. You have another problem with air getting in the fuel system. I suspect it's back at the engine. If you recently changed fuel filters, I would start looking at them.

Pierce

Re: Coach will not start & a diesel leak

Reply #24 – April 02, 2020, 12:03:59 pm

Quote

Did you remove and replace the small center gasket on the filter housing?

Just want to make sure you removed the old gasket. Sometimes it gets stuck on the engine side and you have to pick it out. If the old one is still in there, it could be sucking air into your system.
jor

Affiliate Notice