Slow Fuel leak

Topic: Slow Fuel leak (Read 1413 times) previous topic - next topic

Slow Fuel leak

September 18, 2011, 04:17:30 pm

Hi all!
I keep bouncing around between projects on our "new" 99' Foretravel... Currently preparing to put in bamboo flooring, re-attaching bottom latter (rusted star nuts!), reconfiguring rear TV cabinet space, removing U-Line ice maker (PM me if you have interesting trade proposisitions on this item... it had the guts replaced prior to us getting the coach, works great, just need d the space!), installing Splendide 2100XC, LED porchlight conversion (current light does't function), researching steering tires plus many more!

Today's question may be a higher priority! What I had previously thought was oil dripping from the bottom of the engine (dripping off the lowest point), is actually diesel. It drips about once every minute or so. I don't have any blocks made yet, so I can't safely crawl underneathto get up close and personal with it, but I thought some of you savy, experienced Foretravel motorheads (of which I aspire to become a member:)) might have some good ideas about where it might likely be coming from. Any theories?
Thanks!
Don

Re: Slow Fuel leak

Reply #1 – September 18, 2011, 04:33:47 pm

Don, Not sure what engine you have. On my 95 with the 8.3 Cummins I had a persistent leak with no obvious source until an alert mechanic spotted a leak at the cap of the lift pump. It was slight and worse at the end of a long trip. The drip traveled west along the block behind the Injection Pump and then went south appearing to be coming off the crank seal behind the damper pulley, this was the second lift pump that I have replaced.
Gary B

Re: Slow Fuel leak

Reply #2 – September 18, 2011, 04:40:10 pm

Thanks Gary,
Hmm... That sure sounds like a possible culprit! Ours has the ISC 8.3 Cummins. I will take a look from under the bed. Maybe I will be able to see something...

Don

Quote from: Gary Bouland – September 18, 2011, 04:33:47 pm

Don, Not sure what engine you have. On my 95 with the 8.3 Cummins I had a persistent leak with no obvious source until an alert mechanic spotted a leak at the cap of the lift pump. It was slight and worse at the end of a long trip. The drip traveled west along the block behind the Injection Pump and then went south appearing to be coming off the crank seal behind the damper pulley, this was the second lift pump that I have replaced.
Gary B

Re: Slow Fuel leak

Reply #3 – September 18, 2011, 05:23:34 pm

Don, It looks like you have the Cummins ISC 350 HP engine. Normally any fuel leak would be from one of the following; bad hose, loose clamp, defective pump, loose filter, defective fitting. Not likely would be the need for a head, or injector, maybe a high pressure line. In the end you or some one needs to get their eyeballs in there and do some snooping, I am sure once you get into it, the problem can be simply found. Cummins are not complicated engines. You most likely can find the leak fron the rear door or under the bed, using a good flashlight, not a flood light a good spot light works for me.
My other question would be; does it stop after setting awhile ? That will narrow down the area some.
Good luck

Re: Slow Fuel leak

Reply #4 – September 18, 2011, 06:06:56 pm

Don,
When we bought our 99 U270 a couple of years ago we had a leak in a similar area. It was the lift pump leaking. It is an electric lift pump. Cummins replaced it for around $600. I think the pump was around $350 IIRC.

Mark

Re: Slow Fuel leak

Reply #5 – September 18, 2011, 08:33:35 pm

CK your fuel pump and make sure it it is tight. had a fuel leak ant that is what it was.
Tks DAN

Re: Slow Fuel leak

Reply #6 – September 18, 2011, 09:57:35 pm

I have spare star nuts ( SS) if you have a need. I did a write up on the same repair a few years back.

Re: Slow Fuel leak

Reply #7 – September 19, 2011, 12:35:32 am

We also had a leaking lift pump replaced at Cummins about a year ago. Apparently the ULSD does not agree with the original seal formulation in the lift pump (or so the Cummins guys said.) Don't have separate labor figures, but lift pump was $287 about a year ago at Cummins Bakersfield. No obvious fuel dripping before replacement, but the lift pump was wet according to the tech.

Re: Slow Fuel leak

Reply #8 – September 19, 2011, 05:55:58 am

Don, sounds like electric fuel lift pump. It's located on the passenger side, bolted to the engine block. It's not a cmplicated fix, but it is hard to get to 1/2 way from the top and bottom of the engine. If it is leaking get your hands on the new one before you start changing the old one out, it helps with where the bolts are if you can look at it. Takes about an hour, and you will have to prime the fuel system fuel system to remove the air fron the lines.

Re: Slow Fuel leak

Reply #9 – September 19, 2011, 08:41:28 am

What would be the part number for the lift pump, seems to be a pattern here, probably aquire one for backup. 99 320 450hp celet plus. thanks jc

Re: Slow Fuel leak

Reply #10 – September 19, 2011, 09:29:51 am

Need your Cummins engine number #
With that number I can look it up on Cummins QSOL

Re: Slow Fuel leak

Reply #11 – September 19, 2011, 10:21:26 am

Was the $287 including the parts and labor?
Thanks,
Don

Quote from: Dave Katsuki – September 19, 2011, 12:35:32 am

We also had a leaking lift pump replaced at Cummins about a year ago. Apparently the ULSD does not agree with the original seal formulation in the lift pump (or so the Cummins guys said.) Don't have separate labor figures, but lift pump was $287 about a year ago at Cummins Bakersfield. No obvious fuel dripping before replacement, but the lift pump was wet according to the tech.

Re: Slow Fuel leak

Reply #12 – September 19, 2011, 12:30:41 pm

Dave,

I have looked high and low for the engine number, but I have yet to locate it. Any idea where I can find it? Is it stamped somewhere on the engine or is it a plate like the Allison Transmission?

Also while looking for the engine number from above through the hatch, I noticed that ther is an A/C receptical and an A/C cord dangeling into the engine compartment. One end has the three prong standard plug and the other end has a round connector about an inch on diameter with a locking ring and 2 round holes for a male connector. Anybody know what this is for?
Thanks,
Don

Quote from: Dave M – September 19, 2011, 09:29:51 am

Need your Cummins engine number #
With that number I can look it up on Cummins QSOL

Re: Slow Fuel leak

Reply #13 – September 19, 2011, 12:46:43 pm

Don,

That is for your block heater. Sounds like the engine end has come out/been removed because the element is bad or shorted out.

Brett

Re: Slow Fuel leak

Reply #14 – September 19, 2011, 01:11:55 pm

Don,
Your engine # should be on a plate affixed to the side of the timing gear case. If you are standing at the back of the coach it is on the right side of the case.

Mark

Re: Slow Fuel leak

Reply #15 – September 19, 2011, 02:16:57 pm

Like Mark said it is on the right side above the injection pump, you will need a mirror to read it as you are looking at the engine backwards.

Re: Slow Fuel leak

Reply #16 – September 19, 2011, 02:47:29 pm

Thanks Mark and Bill,

I was able to get it using the camera on my iPhone...

Don

Quote from: Bill Willett – September 19, 2011, 02:16:57 pm

Like Mark said it is on the right side above the injection pump, you will need a mirror to read it as you are looking at the engine backwards.

Re: Slow Fuel leak

Reply #17 – September 19, 2011, 02:50:08 pm

Hi Dave,
The number is 45691640. Is there anything else you can find out about this particular engine as regards previous Cummins maintainence or such?
Thanks,
Don

Quote from: Dave M – September 19, 2011, 09:29:51 am

Need your Cummins engine number #
With that number I can look it up on Cummins QSOL

Re: Slow Fuel leak

Reply #18 – September 19, 2011, 03:08:31 pm

Don, for your engine, the fuel transfer pump assembly is part # 4935007 List $335.20
it is superceeded from #3944386

Found the fuel pump for the ISM is only available in parts, not an assembly.

Re: Slow Fuel leak

Reply #19 – September 19, 2011, 04:00:19 pm

Don, I forgot to mention the other number you will need to get some parts for your engine it is the CPL#, this is the complete parts list for that engine.
Sorry my bad.
Bill

Re: Slow Fuel leak

Reply #20 – September 19, 2011, 04:04:06 pm

Got it! Thanks! It is CPL# 2229... Now I will be able to find my info on the forums:)

Don

Quote from: Bill Willett – September 19, 2011, 04:00:19 pm

Don, I forgot to mention the other number you will need to get some parts for your engine it is the CPL#, this is the complete parts list for that engine.
Sorry my bad.
Bill

Re: Slow Fuel leak

Reply #21 – September 19, 2011, 04:55:35 pm

Thanks a lot Dave, that will help me budget for this fix. By the way, it does seem to stop leaking when the engine is NOT running... Does that narrow down the possibles?
Don

Quote from: Dave M – September 19, 2011, 03:08:31 pm

Don, for your engine, the fuel transfer pump assembly is part # 4935007 List $335.20
it is superceeded from #3944386

Found the fuel pump for the ISM is only available in parts, not an assembly.

Re: Slow Fuel leak

Reply #22 – September 19, 2011, 09:14:45 pm

Quote from: acousticart – September 19, 2011, 10:21:26 am

Was the $287 including the parts and labor?
Thanks,
Don

That was just parts. The labor was bundled in with other repairs I had done at the time.

Re: Slow Fuel leak

Reply #23 – September 19, 2011, 10:47:58 pm

Thanks Brett,

Not an urgent matter for us in California... but one more thing to add to my list of projects!

Don

Quote from: wolfe10 – September 19, 2011, 12:46:43 pm

Don,

That is for your block heater. Sounds like the engine end has come out/been removed because the element is bad or shorted out.

Brett

Re: Slow Fuel leak

Reply #24 – September 20, 2011, 12:19:30 pm

Quote from: acousticart – September 19, 2011, 02:50:08 pm

Hi Dave,
The number is 45691640. Is there anything else you can find out about this particular engine as regards previous Cummins maintainence or such?

Don,
Just call Cummins Customer Service ( 1-800-DIESELS(TM)) and they will tell you everything that have. Didn't you get any maintenance records with your coach? If you stop in at a local Cummins service center, they should be able to pull it up on their computer and print it out for you.

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