ajl
Oregon
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Joined: 03/09/2005
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I drive a 1999 34 foot itasca on a freightliner chassis. I'm running a 5.9 cummins isb with an allision mt643 tranny.
The unit seems to run out really well and is still maintaining good fuel economy. I have kept up on all of the usual maintenance items like air filters, both fuel filters, oil changes and all. And the local cummins dealer has done all the other maintenance, IE valve adjust, coolant flush, tranny service and all. And the unit has 60,000 miles on it.
But lately it has lost some of the top end power. It just doesnt pull the hills as well and it has a little bump in the motor like its missing a slight beat. (very Minor but I notice it)
The intake and exhaust appears tight.
I do not have a boost gauge so I don't know if i'm losing some power there. Do turbos give it up after a period of time?
Maybe some folks can give me some ideas to check off the list before going to the shop.
Thanks
AJL
1999 34' Itasca DP on a Freightliner
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Tom/Barb
Oak Harbor
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Joined: 10/16/2009
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every body lost power when the new sulphur less fuel is used.
2000 Newmar mountain aire 4081 DP, ISC/350 Allison 6 speed, Wrangler JK toad.
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ajl
Oregon
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Joined: 03/09/2005
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Yea i know about the fuel thing. This has been going on for the last 6 t0 9 months or so.
AJL
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J Walker
Oakton, Va
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Joined: 06/12/2003
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There are several things that could explain the power loss. A likely cause is the turbo boost. Of course the air filter should be changed on a 2-4 year schedule. Air leaks in the charge air cooler or its connections could be the cause. The connection of the turbo to the intake manifold could be the cause, and this happened to a friend. The next thing to check is the fuel filters. Beyond that it will take a shop to check injectors and a lot of other things. A Silverleaf VMSpc monitor would really help. For example you could monitor turbo boost and perhaps find the problem.
Jim Walker
2000 34' Damon Ultrasport DP
2009 Malibu
Brake Buddy
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bluwtr49
Green Valley, AZ
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Joined: 09/12/2005
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Could you still be running on winter blend fuel??
Dick
2000 40" DP Beaver Patriot Thunder Cat C-12 425 HP, 1550 Tq
1997 Jeep GC Limited ---toad
2008 Toyota Tundra Crew Max Limited TRD (Retired)
2009 Cougar 268 RLS ~8700 lbs road wt (Retrired)
2006 Jeep Liberty Turbo Diesel.....TV in Training
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wolfe10
Texas
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Joined: 10/08/2000
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With a diesel, any time you have a power loss under load, changing the fuel filters is the first thing to do.
If that doesn't do it, then DO take it to a Cummins dealer.
Brett Wolfe
1997 Safari Sahara 3540
EX: 1993 Foretravel 36' U-240
FMCA Forum: www.community.fmca.com/index
Diesel RV Club:http://www.dieselrvclub.org/
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ScottG
Bothell Wa.
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Joined: 02/25/2005
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I agree with Brett, absolutely anytime it doesn't run right change the FF first even if you just changed it a few hundred miles ago. One tank of bad fuel can go through several filters fast ~ BTDT.
Also, you need to monitor your fuel pressure with either a gauge or an add-on idiot light. If the lift pump dies it will run fairly normal but it will more than likely kill the injector pump.
Scott, Grace and Wesly
2003 Dodge 3500 4x4, 6 speed Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.
H0NDA eu2000i
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bob_b
Souderton, PA
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I have a Cummins 5.9 and you'll know when the fuel filter is getting clogged. You'll see an intermittant drop of 500 RPMs on the tach when you have it under full load. This has happended twice over the years. I always carry a spare fuel filter and a two quarts of Dextron III to fill it with. Make sure to fill the filter using one of multiple small holes and not the large center one (your injectors will thank you)
If I am too far from home, I'll just fix it at the next convenient location. If I am less than 100 miles from home, I'll limp it home and fix it later.
'93 Itasca Suncrusier diesel towing a '05 Honda CR-V.
Bob, Pam(DW), Bridget(DD) and Christine(DD)
See you at most of the Penn State tailgates
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1fastdad
mo.
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Joined: 08/27/2007
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Another posibility is an air leak on the suction side of the fuel system.
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city slicker
dixons mills al
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more then likley lift pump or injector pump. That is what was wrong with mine had little skip ever once in a while. Thanks to dsl that is what cummins tect said, anyway it fixed mind 82000 on engine
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