Dear RV.net family, I am planning to take my RV into Freightliner tomorrow. Just wondering if any of you have experienced the below before, advice or guesses? I promise to keep you posted on what service center says. With warm regards, James2008 Gulfstream Tourmaster RV, 64,000 milesFreightlinerCummins ISC 3601.) RV not able to keep steady 55 mph on the freeway, even with pedal to the metal. Low engine power, slow to no acceleration on uphills, could not go past 45 mph on uphills. 2.) Sometimes whistling, hissing, rattling noise during acceleration. 3.) Exhaust brake also very weak. 4.) Fluid leak on passenger-side of engine around fuel lift pump & air compressor?Freightliner Help Line says to check turbo, CAC, air filter, clamps, etc.

I'd bet a dollar to a doughnut that: If you open the engine compartment, run your hand around the 1" rubber hose on the passenger side of the engine from the bottom of the intake manifold to the air compressor, you will find a hold big enough to stick your finger in it. And It will probably be right next to where it connects to the air compressor. I had the same symptoms, whistleing noise, lack of power and threw a lot of parts at it until someone on this forum gave me the above advice. $40 later and a new hose all is good.

Also, look for signs of an exhaust leak (black/soot) between head and exhaust manifold, the manifold itself and exhaust manifold to turbo. Any leak between the engine and turbo will diminish power as will any leak upstream of the exhaust brake lessen braking HP.

Open engine compartment an the banjo fittings on the fuel transfer pump might be leaking so carefully tightnem them.Have you replaced the first fuel filter an cut it apart an if full of black goo you have bacteria in fuel.Do not be in rush to change final filter as you must be VERY CAREFUL NOT TO GET DIRT IN IT! Also NEVER check for leakks with fingers an engine running as high pressure spray entering your skin will give you blood poisoning

Please let us know what you find out! Good luck, I am hoping for the $40 fix for you!

Have you located the problem yet?????

Cummins ISC low power problem | Good Sam Community

robertbenita
Explorer
Jun 28, 2015
Wow! Please enjoy some trouble free camping for a while. You have earned it!
wantabe351
Explorer
Jun 26, 2015
Im a 5th wheel camper that tows with a 05 Dodge3500PU with a Cummins..Being a former Dodge Mechanic, allows me to fix most things on the truck or camper....We, my wife and I talk about switching to a class A, most likely a used 40-42' DP...Then I read post like this that has happened to you and a cost of 1,800$ for a problem of no power..1,800$ to me is some nice upgrades that I could do to the PU or the 5er...I know it happens rarely but the though of it is in my head and we travel out west to the Rockies ever other year, so we like to travel with our RV. The best of luck with your A class and enjoy the summer
mtrumpet
Explorer
Jun 19, 2015
univmd wrote:
Update today:

Repaired. CAC pipe on exhaust side had hole in it, so Cummins replaced pipe. Fuel pump mounting flange leaked oil, so they replaced o-ring. Parts $371.53. Labor $1456. Total with tax & fees $1863.76

Yikes!:E
univmd
Explorer
Jun 19, 2015
Update today:

Repaired. CAC pipe on exhaust side had hole in it, so Cummins replaced pipe. Fuel pump mounting flange leaked oil, so they replaced o-ring. Parts $371.53. Labor $1456. Total with tax & fees $1863.76
univmd
Explorer
Jun 12, 2015
Update today:

I did not hear from Cummins. So I called them today. Apparently the wrong part came in. So they have to reorder. They are closed on Saturday & Sunday. Cummins says part may arrive Monday. Will continue to keep you posted...
Snomas
Explorer
Jun 11, 2015
Could be some bad injectors, they can cause the same symptoms.
wolfe10
Explorer
Jun 10, 2015
Ya, will want details. Hose and fixing oil leak at lift pump sure does not sound like $1800.
univmd
Explorer
Jun 10, 2015
Today's update:

Cummins called, they said that there is a hole in the hose between the turbo & CAC. Also the fuel pump mounting flange is leaking oil. ECM also says turbo actuator issue, but they found nothing wrong. Cost to fix $1872. They will get parts tomorrow, and fix tomorrow night.

I will continue to keep you posted, and let you know the details of cost once I get an actual receipt in hand. Thank you everyone for your continued advice, help, and tips!
Ivylog
Explorer III
Jun 09, 2015
If Cummins find Code 329, do not replace the lift pump until you read my post on what could have been a $15 fix.
I had much the same problem, but the engine would miss and shake the MH when trying to go up a hill or over 50 mph.
John___Angela
Explorer
Jun 09, 2015
Thanks for sharing.

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