My 2001 Holiday Rambler has a 5.9 Cummins ISB engine. It has about 60,000 miles on it. Runs beautifully.
My only issue seems to be occasionally it can take a while to start. If it is hot it NEVER does this. If it has been parked overnight it rarely does this (but sometimes), if it has been parked for a week or so, or longer it takes a bit of time to fire.
It rolls over fine, and quickly, but takes maybe 15 seconds on the starter twice then fires and runs perfect.
I have tried cycleing the ignition a few times to run the plenum heat twice, but seems to make no difference. It always starts, but can be slow.
Any of the experts here ever seen this and know how to fix it?
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2003 Monaco dynasty chancellor
Toronto, Ontario, Canada.....well some of the time.
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Monaco Owners Club Freightliner Owners Club Holiday Rambler Owners Club
Join Date: Jul 2009
Location: Spring Hill, Florida
Posts: 1,380
First get a sign-in to Quickservecummins.com. There you can learn the parts to your engine by your serial number. It even helps with diagnostics.
Ok I explain a few things about my ISB and it may apply to you. My fuel system draws fuel from the top mounted connection on the fuel tank and runs (SAE 30JR7 tubing) to a chassis 5 micron filter and there to the Lift Pump. It is mounted on the passenger side of the engine. After the lift pump it is routed to the engine fuel filter and water separator. From the fuel filter it goes to the VP44 injection pump that supplies fuel at required pressure to the injectors.
To find the Lift Pump first find the engine filter and follow the inlet line back to the lift pump. The job of the lift pump is to provide pressure to the VP44 injection pump. You should always know what the lift pump pressure is because if it falls to 5-6 PSI you will be in danger of losing your VP44. It could be the cause of hard starting. VP44 cast a lot more than a lift pump. Although you will get a variety of opinions you are pretty safe as long as your above 10 psi.
I get my lift pump pressure from one of two openings on the top of the engin filter. There are two plugs(inlet and outlet 1/8 NPT) that you can remove to mount a gauge. For mine I have transducer installed that gives me a front readout at all times.
What complicates this is the standard lift pump have a hard time drawing fuel such a long distance to the Motorhome tank and still keep up pressure. I installed a FASS DRP lift pump to keep my pressure up but there are other options.
So, What is your lift pump pressure? Find out now or pay later(lol).
As Greystoke has mentioned , the ISB lift pump is a common failure on this version of the 24 valve engine .
In the first picture ; green box ; is the lift pump , yellow arrows the fittings he described for fuel pressure testing .
Second picture a new lift pump .
You need to be aware that a failed lift pump will cause the VP-44 injection pump to fail in short order , and the price of the VP-44 will make you think they're gold plated.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Thanks so much. Man I love this forum! . Sounds like a great project for me. I’ll order a pressure gauge and check that out.
I read somewhere that there is a single computer board on the fuel system that requires fuel flow to cool it. And that there is a small pump that if it fails could fry this one board. Is that the same pump?
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2003 Monaco dynasty chancellor
Toronto, Ontario, Canada.....well some of the time.
Thanks so much. Man I love this forum! . Sounds like a great project for me. I’ll order a pressure gauge and check that out.
I read somewhere that there is a single computer board on the fuel system that requires fuel flow to cool it. And that there is a small pump that if it fails could fry this one board. Is that the same pump?
The fuel cooled ECM mount plate isn't on this version of the 5.9 , to the best of my knowledge that came in with the HPCR ( High Pressure Common Rail ) injection system , late 3003 or 2004.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
The answer to this may make me feel dumb so please be gentle.
Last summer I ran the rig out of fuel. Actually made the planned fuel stop but could not get in to get diesel and came up about 2 miles short of the next one.
I Carry extra fuel. Dumped in 5 gals. Then researched how to bleed it. Was told turning on the ignition and bumping it would run a pump and bleed it if you loosened the return line.
Bumping the starter did nothing. Did it a dozen times and nothing. Cracked the injectors (well 4 of them I could reach easily) and rolled engine with the starter. Just like the old diesels I used to drive in the 70’s. Took a few minutes of rolling. Cooling, rolling, cooling. Some fuel shows up around the injectors so I tighten them back up and she starts with some complaining (probably the 2 cylinders not firing yet).
I assumed the instructions I got were flawed or for the wrong engine. Is it possible this was another symptom of a failed lift pump?
Monaco Owners Club Freightliner Owners Club Holiday Rambler Owners Club
Join Date: Jul 2009
Location: Spring Hill, Florida
Posts: 1,380
Quote:
Originally Posted by AirBossdavid
The answer to this may make me feel dumb so please be gentle.
Last summer I ran the rig out of fuel. Actually made the planned fuel stop but could not get in to get diesel and came up about 2 miles short of the next one.
I Carry extra fuel. Dumped in 5 gals. Then researched how to bleed it. Was told turning on the ignition and bumping it would run a pump and bleed it if you loosened the return line.
Bumping the starter did nothing. Did it a dozen times and nothing. Cracked the injectors (well 4 of them I could reach easily) and rolled engine with the starter. Just like the old diesels I used to drive in the 70’s. Took a few minutes of rolling. Cooling, rolling, cooling. Some fuel shows up around the injectors so I tighten them back up and she starts with some complaining (probably the 2 cylinders not firing yet).
I assumed the instructions I got were flawed or for the wrong engine. Is it possible this was another symptom of a failed lift pump?
When you get on quickserve you can read about Cummins procedures. But in general if you change a fuel filter or quickly open a line you can bleed by turning the key on (watch lift pressure go to about 5) then bump. After about 25 seconds Lift pump goes to 0. Turn key off. Repeat maybe 5 times. Too much air will cause lift pressure to be low. If you have too much air in lines this will not work. The idea is to push pressure through the VP44 to the fuel return line to the tank. The fuel will pass through an overflow valve at the outlet of the VP and let the air out to the return path. If you run out of gas more drastic measures are required. When you Bump open a line at one of banjo fittings. Most ISB techs recommend the banjo at the entry point to the VP. Won't work for us since you can't get to it because of the compressor. So cummins on quickserve recommends cracking open the banjo at the outlet of the VP which you can reach. Keep bleeding until NO bubbles are present. Now you are ready to bleed the injector tubes.
So while your bleeding insure your lift pressure is up. If not fix this problem first.
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