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motorhome got governed

Not on any searches I could find was the issue we had returning home. Traveling with cruise set at 57 mph. came to the 8 mile 6 % Sherman downgrade north of Bishop. Shifted to 4th. gear and pulled the retarder back 2 notches. Watched the VSMpc retarder temp like a hawk. Had to use the brakes a few times to keep speed under 60 mph. Retarder temp never exceeded 250 deg. ran in the 230's most of the time down the grade. At the flat at the bottom shifted back to 5th. and turned the retarder off. When I pushed on the throttle nothing happened we were still at 55 mph. My first thought was the retarder was stuck but retarder temp was back to 210 so I ruled it out and thought fuel filter problem. When the coach got down to 50 mph. it stayed there so I thought maybe ecm error even no codes were showing on the VSMpc and all numbers were good. Pulled over and shut off the coach for a minute and restarted and when I took off all power was back. Great I told Lynda no issue to deal with. then at 50 mph. the coach would not go faster. Looked and saw the cruise set on the VSMpc showed the original mph when we started down the grade. Turned of the cruise and the 57 mph stayed showing on the VSMpc. At this point I was going to continue home at reduced speed and deal with it at home. At that point the speed limit for Bishop started going down until it reached 30 mph. and we drove through town and when the limit went back to 55 mph for towed vehicles throttle worked until the 50 mph again. I then turned the cruise back on to see if I could see any change, there wasn't the VSMpc still showed 57 mph. I used the up button on the cruise and the coach went to the 57 mph. Turned the cruise off and backed down to 40 mph. and hit the throttle again only to go back to 50 mph. Turned on the cruise and hit the up button and we went up until I was at 62 mph. then hit the down button to go back to 57 mph our normal travel speed here is Cal. Now no issue getting home and traveled 150 miles to a rest area and a fuel stop. Getting back on 395 I hit the throttle and the coach didn't stop at 50 just kept going as normal and drove home with no other issue. So after this long post I was wondering what had happened and looking for suggestions.

Chuck
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: motorhome got governed

Reply #1 –
As the engine is throttle by wire I would assume the seemingly  heat related problem is in the ECU.

Why would I suggest this? My 97 showed that its ECU was replaced when near new.  Hot weather area.

I was pushing my coach hard in 100 degree weather downhill from Yellowstone through Salt Lake City to end up the day at below Saint George. Engine temp maybe 200 degrees on my silverleaf

Cruise on at 75mph. Towing 4K pound car. 100 gallons of fresh fuel.

100 miles later the  engine started missing under load.

Our  m11's use the diesel fuel from the tank to  cool the mounting plate behind the engine's ECU. Fuel tank normally  runs  hot to the touch.

Foretravel fitted my coach with a 185 degree dynamatic hydraulic thermostat which locked the cooling fans on full high if the engine was at operating temp.

From reading various model year literature it showed that the 99's went to 10k tow rating and the literature mentioned a fuel cooler.

No such thing on 6k# tow rated 97's or 98's. My Feb 97 build was one of the first with a red top 450hp.

I understand that the majority of fuel going to the engine  is unused by the engine and used for ECU and head cooling instead and then returned to the tank which unlike trucks is in a closed compartment so my/our fuel  continues to get hotter and hotter.

If your tank was down on fuel the tank could get hotter quicker?

Heat failed my ECU for the second time. I am wondering if your ECU was showing cumulative heating issues? We live in the west with heat and mountains.

My opinion is that is why Foretravel upped the m11's cooling fan temp control to max cooling and restricted my 97 and the 98's to 6k tow.

Almost has to be ECU as it's intermittent. Does your 99 have the fuel cooler? My ECU got hot enough over enough years to fail an internal ECU soldered circuit.

Wonder if the ECU stores codes?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: motorhome got governed

Reply #2 –
Quote from: craneman –
Not on any searches I could find was the issue we had returning home. Traveling with cruise set at 57 mph. came to the 8 mile 6 % Sherman downgrade north of Bishop. Shifted to 4th. gear and pulled the retarder back 2 notches. Watched the VSMpc retarder temp like a hawk. Had to use the brakes a few times to keep speed under 60 mph. Retarder temp never exceeded 250 deg. ran in the 230's most of the time down the grade. At the flat at the bottom shifted back to 5th. and turned the retarder off. When I pushed on the throttle nothing happened we were still at 55 mph. My first thought was the retarder was stuck but retarder temp was back to 210 so I ruled it out and thought fuel filter problem. When the coach got down to 50 mph. it stayed there so I thought maybe ecm error even no codes were showing on the VSMpc and all numbers were good. Pulled over and shut off the coach for a minute and restarted and when I took off all power was back. Great I told Lynda no issue to deal with. then at 50 mph. the coach would not go faster. Looked and saw the cruise set on the VSMpc showed the original mph when we started down the grade. Turned of the cruise and the 57 mph stayed showing on the VSMpc. At this point I was going to continue home at reduced speed and deal with it at home. At that point the speed limit for Bishop started going down until it reached 30 mph. and we drove through town and when the limit went back to 55 mph for towed vehicles throttle worked until the 50 mph again. I then turned the cruise back on to see if I could see any change, there wasn't the VSMpc still showed 57 mph. I used the up button on the cruise and the coach went to the 57 mph. Turned the cruise off and backed down to 40 mph. and hit the throttle again only to go back to 50 mph. Turned on the cruise and hit the up button and we went up until I was at 62 mph. then hit the down button to go back to 57 mph our normal travel speed here is Cal. Now no issue getting home and traveled 150 miles to a rest area and a fuel stop. Getting back on 395 I hit the throttle and the coach didn't stop at 50 just kept going as normal and drove home with no other issue. So after this long post I was wondering what had happened and looking for suggestions.

Chuck
Quote from: craneman –
Not on any searches I could find was the issue we had returning home. Traveling with cruise set at 57 mph. came to the 8 mile 6 % Sherman downgrade north of Bishop. Shifted to 4th. gear and pulled the retarder back 2 notches. Watched the VSMpc retarder temp like a hawk. Had to use the brakes a few times to keep speed under 60 mph. Retarder temp never exceeded 250 deg. ran in the 230's most of the time down the grade. At the flat at the bottom shifted back to 5th. and turned the retarder off. When I pushed on the throttle nothing happened we were still at 55 mph. My first thought was the retarder was stuck but retarder temp was back to 210 so I ruled it out and thought fuel filter problem. When the coach got down to 50 mph. it stayed there so I thought maybe ecm error even no codes were showing on the VSMpc and all numbers were good. Pulled over and shut off the coach for a minute and restarted and when I took off all power was back. Great I told Lynda no issue to deal with. then at 50 mph. the coach would not go faster. Looked and saw the cruise set on the VSMpc showed the original mph when we started down the grade. Turned of the cruise and the 57 mph stayed showing on the VSMpc. At this point I was going to continue home at reduced speed and deal with it at home. At that point the speed limit for Bishop started going down until it reached 30 mph. and we drove through town and when the limit went back to 55 mph for towed vehicles throttle worked until the 50 mph again. I then turned the cruise back on to see if I could see any change, there wasn't the VSMpc still showed 57 mph. I used the up button on the cruise and the coach went to the 57 mph. Turned the cruise off and backed down to 40 mph. and hit the throttle again only to go back to 50 mph. Turned on the cruise and hit the up button and we went up until I was at 62 mph. then hit the down button to go back to 57 mph our normal travel speed here is Cal. Now no issue getting home and traveled 150 miles to a rest area and a fuel stop. Getting back on 395 I hit the throttle and the coach didn't stop at 50 just kept going as normal and drove home with no other issue. So after this long post I was wondering what had happened and looking for suggestions.

Chuck
Strange that is, ive always found that on cruise control whatever speed it is set at, as soon as you hit the brake the cruise control disconnects,
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: motorhome got governed

Reply #3 –
Also when the retarder is activated the cruise also disconnects. But the cruise was not holding me back at 50 the throttle was.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: motorhome got governed

Reply #4 –
Chuck,

I would check the throttle position sensor first.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: motorhome got governed

Reply #5 –
Long shot, but do you have a floor mat that might have temporarily gotten underneath the pedal?
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: motorhome got governed

Reply #6 –
Unfortunately or fortunately the problem went away after the fuel, rest area stop, so hard to diagnose. Scott suggested I check for Allison codes to see If anything is there. No engine codes showed up while the problem existed. Experience tells me it was heat related as when everything got cooled down the problem left.

Bob I have the fuel cooler from the factory and was just at a half tank. The downgrade was what caused the issue and no engine load while going downhill to heat the fuel.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: motorhome got governed

Reply #7 –
Quote from: craneman –
Also when the retarder is activated the cruise also disconnects. But the cruise was not holding me back at 50 the throttle was.

Mine is wired so that the retarder engagement does not turn off the cruise.  I used to set muy 3176 marquis so that the jake did not disengage the cruise either
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: motorhome got governed

Reply #8 –
Quote from: Caflashbob –
Mine is wired so that the retarder engagement does not turn off the cruise. 

Let's stick to the troubleshooting topic at hand and not veer off into optional wiring/function choices.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: motorhome got governed

Reply #9 –
Can you see throttle position on the vmspc? also did it accelerate at normal power to 50, then just hold there? Or did it creep up and hang out at 50 ish?
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: motorhome got governed

Reply #10 –
It ran from a standstill to 50 like a hot rod. It had to be a sensor malfunction but, which one. Trans speed sensor, TPI sensor or one that I am not aware of?
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: motorhome got governed

Reply #11 –
The way you are describing what happened sounds exactly like the engine was limiting the speed to 50. But I wouldn't think the cruise control would allow you to go over the limit. If there was any sort of derate from the engine due to anything, there would have been an error code. If there was a bad sensor, or it was getting bad data, there should have been a code. This is a very odd one. The fact that it fixed itself after the fuel stop and I'm guessing the engine was off for a bit, makes me thing it was just a glitch in the engine ECM and restarting it fixed it. The engine ecm will stay powered up and running for a bit after turning the key off, so the first time you stopped and restarted, it may not have cleared itself. Its still really weird.
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: motorhome got governed

Reply #12 –
That is as good a guess as any. The cruise was set at 57 but the throttle limited me to 50 when I got the cruse working that let me go as fast as I set the cruise.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: motorhome got governed

Reply #13 –
Quote from: craneman –
That is as good a guess as any. The cruise was set at 57 but the throttle limited me to 50 when I got the cruse working that let me go as fast as I set the cruise.

You might look for physical damage/wear to the electronic throttle  foot pedal.  Only 25 years old.....a bad signal from it could cause issues. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: motorhome got governed

Reply #14 –
Morning Chuck,
I would look around to eliminate any thing worn or obviously damaged.
I wouldn't throw any money at it until it fails again.
Then you can find the problem.
Getting stuck at 50MPH isn't that bad.
If some component in the system allowed that to happen you will probably see it again.
John Duld
1995 U320C SE 40'

Re: motorhome got governed

Reply #15 –
Chuck, similar issue with my sons M/H Cummins. The cruise would allow it to have more speed. Turned out to be throttle pedal potentiometer. Cleaned and lubed solved the problem. Just a maybe. Jim. 
Jim and Dona
2002 U295 36'
Lily, blue healer. Our fury person
Manx mid travel Ecotec turbo
2022 Bronco badlands Sasquatch
Trail 90 and 110cc
 

Re: motorhome got governed

Reply #16 –
The VMSpc should see Throttle Position from the engine ECM. The pedal is wired straight to the ECM, input should range from 0.5v to 4.5v. The ECM will report this back out on the CAN network as a %. Might be worth adding that as a readout and keeping an eye on it.
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246