Lift pump replacement 2004 Cummins ISL

[Hooligan]

Online search "low fuel pressure light" gives several sources.

This one has Light kit and a gauge kit. http://www.8lugtruckgear.com/Airdog-...ight-p573.html

Local Pensacola Fuel Injection has slightly better prices. DODGE 5.9L 03-07 :: FEED PUMPS & LOW PRESS LIGHT KIT - Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder

Concern is loosing pressure to the injector pump, only light would be in the line after the filters...either filter clogs or lift pump fails-- light comes on.

[texasford]

I thought the 2004 ISL engines used common rail injection instead of the CAPS system.Am I wrong?

[diamantejim]

Our Winnebago 36' 2006 Journey with ISB 5.9L 300HP Cummins is experiencing loss of power also. We had a diagnostic test done on it at idle and all the parameters were good but it continues to have power loss under load. We take it in to the shop Wednesday if we can get it there. We have had all the filters changed since we bought it recently and it is still doing it. The fuel filters have been changed many times as we go back over the records with less than 30,000 miles total time. Folks, this cannot be a fuel filter problem. The sensor on the outside of the filter indicates low pressure. I'll bet that if the sensor were on the inside it would also indicate low pressure, meaning that the low pressure is being developed on the tank side. I think most of you are right that the culprit is the lift pump or the injector pump. Too many people with the same problem, Cummins should have a permanent fix for this, calling them Monday.

[Smitty77]

Hi Texasford,

I thought that the 04 had Common Rail too, and so did the dealer helping me with the purchase. Turns out that though I have an 04 modle, my coach was built in Sept 2003, and the engine serial had a build date of July 2003. It is a CAPS.

So my caution to all, is to pull the serial number, and research the specific engine. I had the coach for close to 2 years before determining the rig had CAPS...

Best ot all,
Smitty

[Genset]

Yes, Anytime anyone wants info on any Cummins, you will save your self a lot of trouble is you would just have your engine serial number number with you, other wise you are GUESSING and HOPING, I do not do well doing either, go get the numbers.
Amen
Dave M

[Coma]

FWIW the lift pump in those years is prone to leaking because of ULSD. It shrinks the seals, upper for the pump side and lower for the electrical connection. I had mine replaced and it looks different than the old one. I'm glad I had Cummins do it because the ins and outs were in different places.

[texasford]

My 2004 DSDP was built January 2004.I called Cummins with the serial number and found out mine is also a CAPS pump.I previously had a 1999 DSDP that had the 8.3ISC that had a CAPS pump.I replaced the lift pump on it at 25,000 miles after I found fuel puddles under the rear of the coach.I changed that one myself and would not recommend doing that.You have to get to it from above and below and every other impossible position you can imagine getting in.

[diamantejim]

I ended driving our Winnebago Journey to Mid-South Cummins in North Little Rock, Ar. even though it was sputtering away with my wife following just in case. The Cummins Shop took it in right away, ran the diagnostics and found the Lift Pump had failed completely so when extra power was demanded enough fuel was not being provided. They had it replaced and out the next day. Also, they recommended the lift pump be placed away from the engine block so the engine vibrations would not create problems for it which is a special kit. It ran like a champ for the 1100 mile trip to warm weather for a couple of winter months. Glad we decided to get an extended warranty policy as they took care of the cost beyond my deductible. After reading all the blogs about what was occurring with loss of power I had decided it was the lift pump since the fuel filters had been changed.

[robinkletke]

Final answer on my original issue. The lift pump had failed. Tried to tighten the 3 mounting bolts and ended up stripping one. (sitting in the WalMart in Pendelton OR). I had a replacement with me, but couldn't get one of the fuel lines off !!

Ended up dismantling the pump/manifold on the coach. Doing the same to the new pump and piecing back together. This got us to Florida and back - although the power loss was still happening.

On the way back thru the Rockies, the power loss got much worse. By the time we got home, it was pretty bad. Took to the Cummins place and they couldn't find anything. They indicated a restriction in the line somewhere, but didn't know where.

High pressure pump - OK. Filters - OK, disconnect the tank and run from Pig - OK.

They offered to drop the fuel tank and clean it out - $3k+ and I said no. Finally a tech applied back pressure to the tank pickup and heard a "pop". problem solved.

Still don't have a firm answer, but think there was sludge buildup in the pickup line. It allowed some fuel to flow to the engine, but restricted. Back pressure fully plugged it up and eventually more pressure purged whatever was in there.

Anyway, the coach is running good again !

[Coma]

Glad you finally resolved it.

If the debris left under the cabinets from the build is any indicator, there is no telling what was plugging that line.

[Smitty77]

Originally Posted by neilking

The lift pump doesn't do anything after the engine is running.

I found this comment from Neilking to match my most current research. I visited with a tech at the local Cummins Cal Pacific, in El Cajon, CA, and asked questions about the Lift Pump. This Tech is one of their more seasoned vets, and I feel he gave good info...

His comment was that many people confuse the ISB's Lift Pump problems with the ISC and ISL. He supported that once the engine is up and running, the Lift Pump is pretty much dormant in the fuel feed process. In his opinion the ISL CAPS of the 2004 and earlier vintage, were no more prone for problems then the Common Rail. One exception, was early problems with ULSD. He mentioned the fuel line problems of many coaches.

When asked, he saw no need to augment the CAPS ISL with an aftermarket fuel pump, as many do with the Dodge ISB's. He did say that this could be coach specific, as some coaches had better fuel pumps from the tank then others, but he said he would not spend the $$ on this if no current fuel starvation problem existed.

When asked about additives, he said that 'ULSD' was all that was officially needed. But, he also said he saw benefit to added lubricants. (I use XPD, asked him about it, and he said again in his opinion - it was one of the better additives. He was catious to not bash a specific brand, but said that again from his years of experience of talking with both OTR and RV owners in with problems, that only a few additives were worth the cost for the added value they provided.)

I also asked him about the seperate Amsoil Cetane that I add, and said 'So, your doubling down on the Cetane?' As he felt that Opti-Lube's XPD had all the Cetane needed for my usage. I may rethink using them both...

So why post all of this. Well the OP's problem did not seem to be so much Lift Pump root cause related, as it was a fuel delivery problem (he mentioned filters, then probable fuel tank pick up sludge problems). May have ruined/starved his Lift Pump and it needed replacement, but does not sound like it was the primary problem.

After talking to the Tech at Cummins, I feel better about the Lift Pump and CAPS probability of being pretty solid going forward. He said he personally knew of many OTR's with smaller ISL (getting used to the ISL being called smaller!) running with several hundred thousands on OEM Lift Pumps and problem free CAPS...

Just info sharimg, consume as you will!

Best to all, and to the OP - Glad your problems are now behind you,
Smitty

[jlfbatonrg]

I'm amazed there were still CAPS ISBs around in 2004. Our ISB is definitely common rail, and the build date is 03-2003. In my discussions with Cummins, I was told no CAPS ISBs for RVs were built after 2002. I don't know if that information is correct, since I have no way to confirm it,. I guess it's also possible some RV manufacturers had some left over XC chassis's and used them in later builds.

[zmotorsports]

Originally Posted by Genset

Yes, Anytime anyone wants info on any Cummins, you will save your self a lot of trouble is you would just have your engine serial number number with you, other wise you are GUESSING and HOPING, I do not do well doing either, go get the numbers.
Amen
Dave M

This is what I had happen to my lift pump in our 03 Dynasty with the ISL. Without looking at my records I believe it was 2008 when I replaced my lift pump. It started to leak around the crimp on the pump after starting to run ULSD fuel.

Technically it was a simple job, however, due to placement of the engine in relation to the frame rail and rear suspension coupled with the fact that I am a pretty good sized guy, access was the more problematic issue. Total time took me about 3 hours and much of that time was "politing asking" the wife to hand me certain tools so I didn't have to keep getting into and out of position under the coach.

Trying to explain which drawer of the tool box the tools were in and what tools I needed to the wife was a true test of our marriage.

Mike.

[phinneyj]

Originally Posted by zmotorsports

.......

Trying to explain which drawer of the tool box the tools were in and what tools I needed to the wife was a true test of our marriage.

Mike.

Only works if your wife either stays out of your tools or puts them back where they go after she tries to either. Fix or build something. :-(