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RV Tech Savvy: Staying On Center

Originally Published in MotorHome Magazine


Q iconI am a current subscriber to MotorHome and enjoy reading the many useful articles. We own a 2006 Jayco Greyhawk 31SS on a Ford cutaway E-450 chassis with V-10 engine. I have never seen the following issue addressed, and it might be that I’m the only one with the issue.

I find it difficult to keep the motorhome centered in the driving lane. Or at least I’m concerned/wondering if I’m staying centered in my lane. There isn’t a hood ornament, or other marking visible from the driver’s seat, and the hood slopes down at a steep angle so there’s no visual clue. The widest part of the body is far enough behind the driver’s seat to be out of peripheral vision. An occasional glance at the rear-view camera can provide a good idea of where the vehicle is at that moment. But what I’m looking for is something that provides constant feedback/reference to lane position. Although they are probably most useful for close maneuvering, I have wondered if bumper end guides like you see on many large trucks would help.

James C. Harris | Wetumpka, Alabama

A iconYou’re not the first person who has expressed this concern, and many owners find “landmarks” in the cockpit and on the windshield to follow to help keep the motorhome between the lines. Lane-departure systems that are becoming more available in the automotive market will help, but it’s not practical to retrofit such a system. I suggest you try the bumper end guide rods. They’re not expensive, and they help indicate where the corners of your vehicle are in relation to the road. You might also try attaching a bit of masking tape to the inside lower windshield to use as a reference point in place of a hood ornament. Additionally, I’d like to hear from other readers if they have found ways of dealing with this concern.

Diesel-fuel Dilemma

Q iconDriving across the U.S., I find it confusing that there are so many different types of diesel fuel. My motorhome has a placard that states it takes ultra-low-sulfur diesel (ULSD). I see low-sulfur, biodiesel and diesel with ethanol. Some pumps are labeled “Diesel #2.” Is that ULSD?

Noel Herft | Yorba Linda, California

A iconThe designation “Diesel #2” does not indicate if it is ULSD. Rather, Diesel #2 essentially denotes its viscosity, and it is by far the most common type of diesel fuel used in highway vehicles for operation in all but very cold weather. Diesel #2 must meet the specifications defined in ASTM Specification D975.

Diesel #1 is used in cold weather because it is less viscous (but it also has less energy per gallon). Diesel “gelling” occurs when the paraffin in the fuel starts to solidify as the temperature drops. At about 32 degrees Fahrenheit, the paraffin wax in Diesel #2 will begin to crystallize and turn the fuel in the tank cloudy. At about 10-15 degrees Fahrenheit, it will start to gel and clog the fuel filters, which may cause the engine to stall.
Diesel fuel that has a sulfur content level no higher than 15 parts per million (ppm) is considered ULSD. This ULSD fuel became required at the pump by law as of December 1, 2010, in the United States, so virtually all diesel fuel you see for sale will be ULSD. “Low-sulfur” diesel fuel contained between 15 and 500 ppm of sulfur, and was phased out and replaced by ULSD.

“Biodiesel” is fuel made at least partially from plant material (biomass) instead of only crude oil and is typically sold as 20% biodiesel, which means the remaining 80% of the fuel comes from crude oil stocks. Most diesel engine manufacturers approve the use of 20% biodiesel in their engines, which is the most common type sold.

Diesel fuel with a concentration of 6% ethanol (D94E6), as compared with pure diesel fuel, has been shown to produce a small gain in power along with an increase in engine block vibration. Despite the increase in power for D94E6 fuel, some irregularity has been observed in engine performance. Increasing the ethanol concentration to more than 8% in diesel fuel resulted in increasing ignition delay and rough running. I personally don’t recommend using ethanol-laced diesel fuel.

GMC Acadia Towing Problem

Q iconEarlier this year, we purchased a 2019 GMC Denali Acadia (3.6-liter V-6, AWD). Before signing the papers, we referenced MotorHome’s Guide to Dinghy Towing, the manufacturer’s specifications and the owner’s manual. All references indicated that the vehicle could be flat towed. We ordered a Roadmaster tow bar and baseplate through Camping World RV & Outdoors. When the parts came in and the vehicle was dropped off for the installation, we were then informed that the baseplate would not work on the Denali model because it was equipped with a Passive Braking System. We found out that the only reference to the Passive Braking System was indicated on the GMC window sticker and in the parts specifications provided by Roadmaster and Blue Ox. No one thought to ask about this system until it was too late. It was a costly mistake for us because we decided to trade in the Denali for the SLT model so that the parts would work. I just want your readers to be aware that the GMC Denali Acadia with a Passive Braking System cannot be flat towed with a Roadmaster or Blue Ox tow bar baseplate. I did not research other tow bar systems.

Dan Gough | Henderson, Nevada

A iconWe started researching this and couldn’t find anything stating that the Acadia with the adaptive cruise control/automatic braking system couldn’t be fitted with a baseplate. When we discussed your concern with Roadmaster technicians, they informed us that early on, they had removed the models with adaptive cruise control from the fit list because GM had changed the part numbers for the adaptive cruise control system. This meant that until a physical vehicle was made available to Roadmaster, the company would be unable to tell if the baseplate would fit or not. It’s common to have components like this change size or move around on a vehicle from one model year to another, and this component can’t be touched or modified in any way. Once Roadmaster was able to get one, the company was able to confirm that the new radar unit was moved to an out-of-the-way location, so installing the baseplate would not be an issue.

Vibration Solution

Q iconI purchased a 2005 Fleetwood Jamboree GT in 2010. In the November 2019 issue, I read about a vibration problem that Dustin Phillips was having with his 2015 Jayco 29MV motorhome (“Noisy Cab Comments and Driveline Vibes”). We encountered a vibration between 58 and 62 mph. Above and below that speed, everything seemed normal. When I got home, I took it to our Ford truck dealer, and the mechanics couldn’t find anything wrong. After two years of trying to determine what was wrong, I found the rear U-joint was out of alignment. It appears it was due to the tapered shims between the rear springs that were installed from the back toward the front. I removed them and installed them from front to back. That dropped the pinion gear down and changed the angle of the rear U-joint. I took it for a test drive and there wasn’t any vibration.

About three months later, while reading an older issue, I read that Jim Kunik (“A Challenge,” April 2015) had a 2005 Jamboree GT with the same problem as I had, and he couldn’t find anybody who could fix it. I found his phone number and told him that I had the same problem, and what I did to fix it. He called me back in about two months and said he found a garage that did the same thing to his motorhome, and it fixed his, also. I contacted Fleetwood about the problem, but never heard a word from them. All the motorhomes had the frames stretched. I’m not sure if it is Fleetwood, Jayco or Ford’s responsibility.

Don Norvell | Gladstone, Missouri

A iconTypically, driveline vibrations are heavy and felt through the seats and floor, rather than through the steering wheel (as with front tires out of balance), and driveline vibrations usually are noticeable over a wider speed range. You may have gotten lucky when you switched the shims around. There is a checking procedure using a special protractor with a built-in level that is used to measure the angularity of the U-joints. I recommend that owners have measurements made before changing pinion angles, and be sure the U-bolts holding the axle to the springs are torqued to manufacturer’s specifications.

Generator Controls Quit

Q iconHave a tech question?We have a 1995 Beaver Patriot 37-foot motorhome that we bought new. Two years ago, on our way to Alaska, I was using the generator and it was working fine. Then I tried to start it again and it would not do anything (it wouldn’t even click). I stopped and went outside and pressed the start button on the generator, and it would start and run just like always. I could shut it off from inside, but to start it, I had to go outside. When I got up to Alaska, I tried to figure out what was wrong; I opened the box on the side of the generator that the wires come into to see if I could find a loose wire or anything else that did not look right. I removed the little control box that was inside of that box and used some electronic spray cleaner and gave it a good cleaning, but that did not do any good. When I got back home, I called the Beaver factory and had them send me a new switch. I installed it, and it did not help. I have tried to trace the wiring to see if there is some damage. Everything is in looms with lots of other wires, so I had no luck there. I wonder if you might have any ideas that might help?

Robert Waller | Buhl, Idaho

A iconThe wiring is probably damaged in the loom. There are special devices that can inject a signal into the wire and a second device that can trace the wire from the outside. You can buy a tracing kit or hire someone who has one (many RV shops and auto electric shops have these tools). You can also use a multimeter and the appropriate wiring diagram to see which contacts in the switch should be closed during the start/preheat process. Have a helper depress the switch while you test with the multimeter. If you can’t find where the break is in the wiring harness (if there is one), you can run new wires outside the loom and put them in their own little loom, cable-tied to the main loom.

More RV Tech Savvy Discussion

Ken Freund portraitKen Freund has been a contributor to MotorHome magazine since 1988, and has written Coach & Powertrain and its predecessor Powertrain Q & A for two decades. He’s been a camping and travel enthusiast since he was a child.



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