Question for you Class A Diesel Pusher Folks

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  You are correct,, the "econo mode" selection changes the shift points 200 RPM to make the engine "lug" more before it downshifts to increase economy,, that's what diesels do.. BUT,, it is not desirable in mountain terrain an will make unwanted engine heat.  Professional truck drivers have a moto: "speed is NOT a consideration when climbing".>>>Dan
 
Yeap, for the motorhome application, Allison uses the Mode switch as the economy mode selection. For other applications, it will often have a different meaning.  If you have Eco Mode engaged, disengage it when hills are encountered.

In practice, though, the Eco Mode for a motorhome has very little effect, no more than a few hundred rpms difference in upshift to over-drive (gears 5 & 6).  It pretty much gets trumped by the power demand on any hill at all, but it may delay the initial downshift from 6 to 5 or 4 by a few hundred rpms (and thus a few moments). Most owners quickly hit WOT (Wide Open Throttle) on any hill climb worth mentioning.  The difference between Peak Torque and peak Horsepower RPMs varies by engine familiy and horsepower tuning, so I can't make any absolute statements about what Eco Mode does.

Brett Wolfe, a very knowledgeable guy, is a fan of the Mode switch, but most owners don't find it helpful. See Brett's explanation of what it does at https://community.fmca.com/topic/1149-allison-economy-mode/
 
Gary RV_Wizard said:
Yeap, for the motorhome application, Allison uses the Mode switch as the economy mode selection. For other applications, it will often have a different meaning.  If you have Eco Mode engaged, disengage it when hills are encountered.

In practice, though, the Eco Mode for a motorhome has very little effect, no more than a few hundred rpms difference in upshift to over-drive (gears 5 & 6).  It pretty much gets trumped by the power demand on any hill at all, but it may delay the initial downshift from 6 to 5 or 4 by a few hundred rpms (and thus a few moments).
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Gary...
I haven't noticed much difference if any. Now, let's get this straight and in default, there's no light and the tranny is in it's regular mode, correct?
When the mode button is pushed, the red light comes on and you're now in Eco mode, right?
 
The function is usually OK for rolling hills where the trans might want to "hunt"at every small grade,, and becomes annoying and unproductive when the engine could easily pull the hill if it would stay in the selected gear a little longer.. I like it for that purpose.>>>Dan
 
I found out not to use the mode when trying to get on a high speed highway. It upshifts too soon. Once up to speed, it isn't helpful to me as th transmission doesn't shift from 5 to 6 until 70mph. And I don't go that fast.
 
You really should consult with Allison on reprogramming the trans,, 6th gear is very desirable for cruising at chosen speeds. (I cruise at 65 in 6th and get 10 MPG most times, mine shifts into 6th at 58 MPH with a total weight with towed of 31300.)>>>Dan
 
You really should consult with Allison on reprogramming the trans,
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Don't think he needs any re-programming; just very selective use of the Mode button.  I always found the normal mode to handle just about every situation as well as the engine is able.
 
Last year I had some overheating problems on my way to the Black Hills. Once in Rapid City I scheduled for a service call to address the matter, and one of my requests was to reset the transmission. This removes the learned habits of previous miles and gives the trans a blank canvas to build new a history.
After the service was completed and we picked up the motorhome that first day back on the road was a real eye opener. Especially the initial time pushing the button into drive. The transmission engaged with such force I thought I was at a dragstrip. It was quite violent and quite a surprise. Throughout the day the transmission shifted with authority and without hesitation. Day two was much better, and after the third day all was good. Even after a year since the reset I still feel a transmission that shifts with authority, and not just slip into gear.

Maybe a reset might work without reprogramming


Corky
 
spdracr39 said:
Change your fuel filters. I bet you are suffering from fuel starvation.
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Got it in the shop now. Fuel, air, and oil filters were all new like the previous owner said. Think it is a turbo problem. They said the waste gate wasn?t opening up when we would raise the rpms. My next question is would this entail of a new turbo or is that a repair of its own without replacing. Just wanna make sure I?m not ripped a new one if you know what I mean.
 
emmaus road said:
I just purchased a 2003 Holiday Rambler Endeavor 40 foot 3 slide model with the Cummins 330 Diesel pusher.  While I'm driving, she shifts like a dream, however, when I'm going up hill, and the turbo kicks in, she gets sluggish and jumps from time to time. Almost like a hesitation.  Is this normal at all or should I even feel anything when the turbo kicks in. 
I've always owned a class c Ford so now I get to learn all the ins and outs of the diesel pusher.  I tell you though, I sure am enjoying the bigger tires and quieter ride. 

Thanks for all your advice and help.
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"she gets sluggish and jumps from time to time." Could you add a more detailed description of your statement?  Does sluggish mean: it just slowly looses power? 
Does "jumps" mean you kind of get a feeling of being jerked forward a bit, kind of like a very quick short hit of the brakes?  This jumping or jerking problem is what my fuel starvation problem felt like.  The intake screen on the lift pump was clogged with black rubber like particles. 

Can you recreate the problem by getting on a freeway with light traffic such as early Saturday/Sunday morning and getting the rig up to about 65 and apply the brakes while pressing on the accelerator to keep your speed up.  The idea here is to put the engine under a load as you would find going up a hill.  As long as you only press the brakes pretty hard to very hard for about 30 seconds, release the brakes and then drive for 3-5 minutes to let them cool down before repeating, you won't damage anything or hurt your brakes.

What "shop" did you take the RV to?  A Cummins Factory Service center is an excellent place to go? 

I wouldn't let them work on the turbo w/o a second opinion.  That can get expensive pretty quick.
 
Think it is a turbo problem. They said the waste gate wasn?t opening up when we would raise the rpms. My next question is would this entail of a new turbo or is that a repair of its own without replacing. Just wanna make sure I?m not ripped a new one if you know what I mean.
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Please go back up to Reply 13 where I talked about replacing the turbo.  We just had it done and the difference in performance is like night and day.  We had it done by a diesel performance specialist (would you believe there's an organization they belong to?) in St. George, Utah.  And, yes, it is expensive.

Cummins could not find a problem a year ago when we first noticed the engine was getting sluggish.

ArdraF
 
First I wanna thank everyone for your input. Y?all were almost spot on and some even nailed it.  Turned out not being the turbo waste gate. Took it to a very reputable company in Chattanooga, TN to be fixed after the first shop gave me their opinion.  They changed the 2 fuel filters and road tested and it still bucked under pressure. Then they dropped the fuel lift pump, disassembled it and cleaned it out. Found a little trash but as soon as they took it off a small rock fell out. Put it all back together and now she runs like a 61k mile Cummins should. Bottom line is sounds like my rig had a kidney stone lol. I guess I?d jump and buck too lol. Thanks everyone I?m definitely gonna remember this forum.

Greg
erqmusic.com
 
The good news is that the lift pump intake screen helps prevent expensive damage to the fuel injection system. The bad news is that it is a common source of performance problems when it does its job.  Some loss of power on hills may be the only sign that the intake screen has been "working as designed". Some people who have had this problem multiple times have installed a coarse filter in the fuel inline ahead of the lift pump, making it easy to fix a clog.
 
Gary RV_Wizard said:
The good news is that the lift pump intake screen helps prevent expensive damage to the fuel injection system. The bad news is that it is a common source of performance problems when it does its job.  Some loss of power on hills may be the only sign that the intake screen has been "working as designed". Some people who have had this problem multiple times have installed a coarse filter in the fuel inline ahead of the lift pump, making it easy to fix a clog.
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That was what he was gonna do if the problem continued.
 
Regarding this quote:

ok, my reader says 6 all the time.  That's either a 6 or a G for go lol.  But it doesn't change as the gears shift. 
It only does it going uphill when you can see the turbo gauge going up.  I kinda was thinking it was a fuel or an air intake or something.  But remind you I am no mechanic, but learning little things as I go.
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In my configuration my transmission only has 1 "gear window".  I have a red switch near the gear selector.  When pressed "on" the window shows the gears as they progress and regress.  When pressed "off" the window is always at 6 unless I manually punch in another gear.

I am a newbie and might be stating the obvious - I hope this helps.
 
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