tom538

ISB300 Cummins Diesel Stuttering And Losing Power

14 posts in this topic

The Cummins diesel in my 2004 Expedition is stuttering and losing power when climbing a grade out on the highway. Simultaneously the "check engine " light comes on. Once I have started downhill the ""check engine" light does out and the engine regains power and speed. I had the combo fuel/water filter changed yesterday and the problem temporarily went away. Shortly later the stuttering and power loss returned accompanied with little puffs of black smoke coming out of the engine exhaust pipe. I limped into a campground in Roanoke Rapids North Carolina. A call to the nearest Cummins dealer (60 miles away) suggested that I have the coach towed to the dealership. Anybody have any thoughts on what is occurring? I am very nervous about having the coach towed and wonder if there are any cautions I should be aware of in doing so

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This is a very sad end to a wonderful two month trip to the northeast. Fortunately this is a very nice campground so we are making the best of it.

Thanks for listening.
Tom

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Were the old fuel filters clogged? If so, you may have the new ones clogged as well. Certainly worth looking at the primary filter.

Also, check that the hoses between turbo and CAC and CAC and engine are tight-- loss of boost will also cause the symptoms.

Brett

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We had same issue. It was plugged fuel filters. This occurred when we bought it used and before I was able to do maintenance on the rig. Ended up going to O'Reilly near a campground and changing them in the campground. Filled new filter with diesel before installing and no issues after that.

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Modern day towing involves a large trailer which the wheels slide forward and the back tilts to the ground and the MH is winched on.

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The mechanic at a truck stop who changed the fuel/water separator filter claimed there was no other fuel filter. Thus he missed changing the primary fuel FI.ter if there is one. I am guessing now that there is another filter that should have been changed. Any thoughts in this?

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Your chassis maker determines how many and where the filter(s) are located. The engine manufacturer merely prescribes to what micron rating the fuel must be filtered.

Best filtration setup for a diesel is a primary filter (10-30 micron filter element) with water separator and secondary filter with fine filter element (2-5 micron depending on engine manufacturer's specs).

Yes, there are some chassis with just a single filter.

It is VERY important to know if you have the one or two filter setup. If you have a single fuel filter and someone puts a 30 micron filter element in it, you will basically be throwing "rocks" at your injectors. If you have a two filter setup and someone puts a 2 micron filter element in the primary filter, it will clog quickly and give the secondary filter a free ride.

Please let us know what filter(s) your coach has. And, if you post the filter element numbers, we can verify that you have the correct one(s).

Brett

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My 2004 isb has only one f/w filter on it. I traced lines myself and also had dealer check to be sure. Fuel goes from tank through the lift pump then f/w filter then to high pressure pump.

On mine you do not fill filter with fuel just install and turn key on let lift pump fill filter, open water drain fitting to bleed air.

These motor require about 25,000 lbs of fuel pressure under load or check engine light comes on and it goes into limited mode with low power.

Happened to mine, small internal leak from loose fitting.You need to have it checked by someone with laptop and proper programming to see where problem is. Could be vgt [variable geometry turbo] problem, lift pump, high pressure pump,etc.

Way to many possibilities to guess at.

Good luck,hope your problem is minor.

Dave

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Good morning Tom!

I think your model year has an inline fuel filter that is mounted along the drivers side frame rail. This one is real hard to find or see !!!

Located just kind of behind and above the rear axle.

You might give Freightliner factory service a call, They are located in Gaffney, S.C. off RT. 95.

1-800-FTL-HELP (1-800-385-4357)

You will need the last 6 numbers / letter of you Chassis VIN number.

They should be able to supply the information and part numbers.

Hope the information saves you a tow bill !!!!!

Rich

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Thanks to everybody for their great help in analyzing my engine problem. Here is what happened next. We were towed to a Cummins repair shop today that primarily works on large trucks. They reluctantly agreed to look at my RV as a lot of the large Cummins outlets only do trucks but GOOD SAMS would not pay to have me towed further as they were an authorized Cummins repair facility and could run the Cummins fault code software.

Fortunately, the service personnel were very good and determined that the fault code was low fuel pressure. Based on Rich's posting above, I insisted that they look for a inline fuel filter which they finally found after sending their littlest mechanic under the coach into the area Rich suggested. This inline filter is about the size of a banana ( a straight banana of course). When they disconnected and examined this filter they found it was full of rust and gook and most of the filtration holes were plugged. The mechanic suggested that this filter had not been changed for a very long time. I checked my bills from the Cummins repair facility in Savannah that serviced my coach three months ago and found that I had paid for TWO fuel filters to be changed. The primary inline filter and the water/fuel separator filter which is quite visible. I retained the defective filter and will be having a chat with my Cummins dealer when we get home in the next few days.

The engine purrs like a kitten now and has power to spare on hills.

I was very lucky my problem wasn't any more serious and sincerely appreciate the great information I received from all of you who posted replies to my original message.

Thank you

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Yes, some Freightliner chassis have THREE fuel filters.

The inline one on the frame.

The PRIMARY FILTER/WATER SEPARATOR (with 10-30 micron filter element)

The SECONDARY FILTER (with 2-5 micron filter element).

Always a good idea to check micron ratings of the filters, as a 2, 5, 10, and 30 will all fit the same filter housings.

If you are not sure of the micron ratings they used, post the numbers and one of us can look them up for you.

Brett

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Any idea which chassis had 3 filters? I'm having a PID94 code and have been pulling my hair out trying to figure out.Same symptoms as above..thanks for any imput..I have a 2006 allegro bus 400 cummins/freightliner chassis

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To my knowledge, this filter is NOT on your chassis/engine. But, you can certainly call Freightliner with your VIN to confirm. Here is the information that I have:


Cummins Fuel Strainer: Every Cummins ISB02 RV from FCCC since 9/2002 has a fuel strainer/filter on frame rail: 025-RAC 10. http://www.freightlinerchassisownersclub.org/PDF/ISB02_Fuel_Strainer.pdf

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