Skip to main content ↑ ↓
Topic: Fuel Leak (Read 1264 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Fuel Leak

Yahoo Message Number: 61869
I recently noticed the unwelcome odor of diesel fuel coming from curb side rear. I crawled under the engine and found fuel droplets on the starter motor. I believe the lift pump is directly above the starter motor on my engine. Back in 2007 after the shift to low sulfur diesel I experienced a complete shut down due to leaking lift pump and had the gasket replaced. Is anyone aware of a continuing problem with leaking lift pumps on Cummins engines?
In addition on four or five recent occasions the engine has stumbled (missed) and produced a large plume of white smoke from the exhaust. Wondering if this is related to the fuel leak or is it more likely due to contaminated fuel. All of the occasions have been since the last fill up.

Thanks

Bob Amory

2002 Allure 30760, cummins 350 ISC

Re: Fuel Leak

Reply #1 –
Yahoo Message Number: 61875
Bob, If in fact it is the Lift Pump this unit has, I believe (5) "O"Rings in the ports. These also go bad. I just had my Lift Pump replaced at 90,000 miles on my 03 Allure 1st Ave. ISL 370. Yes they continue to have problems.
If in fact it is the Lift Pump and you intend to keep the coach I recommend you not just again replace Gasket and "0" Rings, get a new unit put on. A new Lift Pump is $377.00 including the "0"Rings, you have to ask your shop to order the "0" Rings as well. Can you believe Cummins ships a new unit less the "0" Rings unless you request in the order. They are made in Mexico.
Also check your Cummins Accumulator Pump System, known as The Cummins "CAPS" it is the big pump with the fuel lines going into the injectors....if that is leaking you are looking at $5,000 and your coach will often show the Engine Warning Light and the coach will stumble...this is most likely this pump as the Lift Pump only comes on when you start the engine, bringing fuel to the engine from the tank.
You may have to take out your bed box cover to accurately determine which unit is Leaking.

Thanks, Mike 03 Allure 1st Ave. #30898

Re: Fuel Leak

Reply #2 –
Yahoo Message Number: 61877
Bob:

Like in the game of Manopoly (sp) go directly to shop do not pass go.
The first sign of a failing lift pump is the dripping of fuel.
The famous gasket is leaking. That won't necessarily stop the engine but the engine attached fuel pump will suck air after the lift pump stops and thast will get you by killing the engine.
I paid the price and had to be towed.
If you can get it to start and continue to run go straight to the shop and have it replaced.
If you are willing to pull the starter and work from the bottom go for the job . Mine was easy and was done by just lifting the bed and removing the big hatch.
The most anoying part of the job is getting the surounding area clean to do the work.
I now carry 2 sets of gaskets and "O" rings and my original pump.
Don't put it off or it will bite you.
James M. Green Intrigue 11021 "Rollingghetto"

Re: Fuel Leak

Reply #3 –
Yahoo Message Number: 61926
Hi Friends, Ken again a Retired Cat Tech! Will be quick on this one, On my 330 ISC A couple of years ago the lift Pump Faild AKA Rubber Gasket! I went to Cummins and just bought the Whole lift Assem. Did the Replacment my self as this is nothing new to me, Since my Coach was 10 years old at the time 98 330, Was MY choice, Funny I did not have Rubber O Rings to replace the Plugs and fuel lines on the pump head? Mine were copper, Just replaced the original copper washers and been two years ago no problems or leaks, As you know Cummins has a gear pump to deliver fuel to the Inj. Pump assem. and the Electric lift pump only cycles once during startup. I saw on the files section the Cummins P/N for the Rubber Gasket! Kudos for all the hard work fellow Owners do for this group and also the great files section of this Group. My friends at CAT tease me thet I bought a rig with a Cummins! Remember if it aint a Cat its a Dog LOL! Again just wanted to add my 2c! Ken 99 Allure 30356 in Hart Ranch Rapid City S.D. on my way to Denver Westminster Elk's.

Re: Fuel Leak

Reply #4 –
Yahoo Message Number: 61988
Hi Jim - Rest assured, I know of what you speak. The last time I experienced the lift pump failure I was at Bird Creek on Turnagain Arm outside of Anchorage. My second tow experience! Then I was carrying the gasket but not now. Didn't know about the O rings till this series of posts! I noticed the leak a week ago and wanted to complete a schedule of touring with our daughter, which we have been able to do. I am in Anacortes, WA and there are no Cummins Facilities near by. But I have an appointment at a Freightliner facility tomorrow morning. Hopefully there is one more start left, but at least getting towed from a campground is a lot safer than the side of the road!

Thanks to all for the posts and the info.

Bob Amory

2002 Allure 30760

Re: Fuel Leak

Reply #5 –
Yahoo Message Number: 61996
FWIW, when I changed my lift pump gasget, I didn't use the O rings because I didn't crack open any fuel lines. From underneath the coach, I was able to remove the pump from the "head" and replace the gasket. I had a helper up top who remove the three 7/16 bolts, while I held the pump from the bottom to keep it from falling off.

Larry, 03 Allure 30856 W/ISL 370

Re: Fuel Leak

Reply #6 –
Yahoo Message Number: 62059
Wow Finally

Now I feel part of the group..lol. what others are experiencing I just had happen . Yesterday when I started up to move to another place had the tell-tale fuel leak sign, so now what is the part number for the lift gasket for the ISL 350 and where did you get it, knew it was bound to happen sooner or later, glad it was sooner, I'm sitting for a couple of months and have time to change it.

Jerry

2004 Inspire 51012

Re: Fuel Leak

Reply #7 –
Yahoo Message Number: 62062
Jerry

The part number for the lift pump gasket on my ISL 370 is 4928511. I think it's the same for your ISC 350 because my friend's 350 was. We got or gaskets (~$6) at a Cummins distributor. You will need your engine serial number when you call Cummins.
It's not that difficult of a job. We did three of them in our park. It might take two hours or less your first time. That includes gaining access through the BR closet floor. You don't have to remove the "head" with all the fuel lines connected to it. Just the electric pump on the bottom of the head. The Cummins techs told us that too. My friend wanted to change the whole pump/head assembly($350?), but the Cummins techs talked him out of it because it is not nessesary. Good luck.

Larry, 03 Allure 30856