Community Forums

Sully · 07-13-2006, 10:10 PM

I have had this problem since soon after picking up the coach. Went to Cummins in Medford and Coburg Or. and they adjusted the droop (don't have the slightest idea what it is) to no avail. Cummins Anchorage came up with a bulletin [I]ISL-CM850 400hp RV Surge in Cruise
The gist of the bulletin is that it is a software issue between the engine and the cc. There is a fix and it is being field tested with release scheduled for 3rd qtr 06. I asked Customer Support to try and get Mike Young to have The fix at Homecoming.

This effects engines built in '03 to present and all other mfg's who use Cummins & our CC.

Sully

Sully · 07-13-2006, 10:10 PM

I have had this problem since soon after picking up the coach. Went to Cummins in Medford and Coburg Or. and they adjusted the droop (don't have the slightest idea what it is) to no avail. Cummins Anchorage came up with a bulletin [I]ISL-CM850 400hp RV Surge in Cruise
The gist of the bulletin is that it is a software issue between the engine and the cc. There is a fix and it is being field tested with release scheduled for 3rd qtr 06. I asked Customer Support to try and get Mike Young to have The fix at Homecoming.

This effects engines built in '03 to present and all other mfg's who use Cummins & our CC.

Sully

Audrey & John · 07-14-2006, 03:06 AM

Can you describe the behavior in more detail? I'm not sure that I have experienced that.

Thanks!

Audrey

ronboc · 07-14-2006, 08:01 AM

Hi -
I'd be very interested to hear more about it too, Sully.

I'm experiencing what I'm guessing is the same thing in a Monaco (same engine & trans, though). Was wondering if it's just me, but now I feel better to know it isn't. And very glad to hear that Cummins is getting their finger on it.

Thanks!
Ron

E & D Wilson · 07-14-2006, 09:18 AM

We have the same 'stuttering'
problem. Apparently it is the cruise control. It does not know what to do, it needs some leaway built into it. If CC is set at 55, it does not have the leaway to choose whether it should go faster or slower. Hopefully the computer 'fix' with take care of this problem.
We have heard two stories, one the fix is ready, and the other is the fix is coming. Take your choice! Which ever, we will be right in line for the fix.
Travel safely out there!

Sully · 07-14-2006, 06:46 PM

Audry,

If you have the problem, you'll know it! As the coach crests the hill it starts to buck very noticeably as soon as you start to descend. It is a condition that only a few of us are lucky enough to have.

Sully

Cedar41 · 07-15-2006, 02:24 AM

Yea, a problem we don't have.

Audrey & John · 07-15-2006, 11:53 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sully:
\If you have the problem, you'll know it! As the coach crests the hill it starts to buck very noticeably as soon as you start to descend. It is a condition that only a few of us are lucky enough to have. </div></BLOCKQUOTE>
Wow! - no, our's definitely doesn't do that! Crested many hills yesterday in cruise - nary a buck!

Audrey

P.S. Knock on wood.

Wil Rathke · 07-16-2006, 04:19 AM

I have a 2005 with the ISL400 and have experienced a slight "surging" going down hill or coasting regardless of using cruise or manual throttle.

Also, I have found that 55 MPH is not a good speed to set the cruise to because the transmission shifts to 6th at 57 mph and back down to 5th at 52 mph depending on throttle and load. On my rig this results in a lot of shifting particularly on a hilly road.

Ted III · 07-16-2006, 03:17 PM

Why not just take it off of cruise control?

Snuggery · 08-14-2006, 06:40 AM

We have the 2005 FDTS with 400 HP Cummins ISL engine.
I think this is the same problem. We first noticed that bucking (vibration) when starting downhill with Cruise Control ON. Then we noticed the same problem even with CC OFF. It seems to be when going downhill with the accelerator pedal pressed just slightly.
The vibration or bucking is DRAMATIC - the whole coach shakes and has rattled screws out, the bedroom doors off track, etc. It does not seem to be related to whether the CC is On or Off, or whether the Jake brake is On or Off.
I think it is something to do with the transmission. Setting the transmission to Economy Mode made the problem disappear for a while. Temperature guage readings are fine and I have checked oil and transmission fluid levels several times as well as looking under the chasis for leaks.

Dave Fernandez · 08-15-2006, 09:29 PM

Hello Everyone:

For my $0.02, when I worked as a mechanic, if a car had a vibration during deceleration or acceleration we would look at the driveshaft, U-joints and check the alignment of the differential and transmission.

Any one of those thinks could cause the vibration on a car maybe in a motorhome?

ronboc · 08-16-2006, 10:15 AM

Good point, Dave.

I once had an British car (TR6) that went thru u-joints faster than it went thru a tank of gas, it seemed. Loved the car, but spent more time UNDER it than IN it.

I think we're talking about a 'bucking' sensation, more than a vibration. Almost as if one is tapping the pedal vigorously on a downhill slope. And at least on mine, it stops bucking soon's I take off the CC. Coincidence?

Ted III · 08-17-2006, 02:26 AM

If you contact WRV they will address this problem immediately. This was discussed at length at the Charlotte pre rally. It is some type of modification that can be corrected rather quickly. Do yourself a favor and contact WRV