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RV Tech Savvy: Fuel Tank Fix

Originally Published in MotorHome Magazine

For those readers who have been plagued by a slow- or incomplete-filling diesel-fuel tank on their motorhome, here is another possible solution.
I have a 2007 40-foot Winnebago Vectra diesel pusher built on a Freightliner chassis. When the fuel tank reaches about 85 gallons (on the 100-gallon tank) during the filling process, the nozzle kicks off and then it takes forever to fill the last 15 gallons. I checked the fill tubes and vent lines (one on each side) for blockage and even opened the fill caps on both sides for better venting, but didn’t have any success in solving the problem.
Finally, after inspecting the fuel-tank configuration, I found that the fill pipes and vent lines are not located on top of the tank; rather, they enter the tank on the side, leaving about 15 gallons of dead air space above the connections. My solution was to install a ½-inch inside diameter vent line in the top of the tank to vent the trapped air, and add an in-line fuel filter to the end of the vent line to prevent dirt and bugs from entering the tank. Now, when the pump kicks off, the tank is completely full. Warning: This modification is not easy and could be dangerous if not done by an experienced technician.
Dave Berkel | Union, Missouri

Thanks for sharing your solution, Dave. There are many coaches out there with this problem. Of course, you are correct that doing this kind of modification requires a lot of experience and know-how, as messing with fuel tanks can lead to damage, injury or death if done incorrectly. There are fuel-tank vent kits available from companies like Tanks Inc. that may be able to help. Check any emissions legality concerns, and check with the chassis manufacturer before modifying.

Throttle Response Lacking
We have a 2012 Winnebago Aspect on a Ford E-450 chassis with a V-10 engine. Since we purchased it in 2013, I have noticed a lot of dead pedal in the throttle, particularly when pulling hills. We also dinghy tow a 2013 Hyundai Elantra, which weighs about 3,000 pounds. I have seen some ads from Hypertech and another distributor for a throttle optimizer (REACT is the Hypertech version). Have you done any testing on these devices? I am considering buying the tow version of the REACT. Basically, it plugs into the throttle wire to enhance the voltage. My issue is that the throttle has little response no matter the transmission setting (tow/haul, lower gear, etc.). We changed the throttle position sensor when we had to replace the fuel pump, and it checked out OK.
Henry Yerger | Tucson, Arizona

Some of the “dead pedal” you refer to may simply be that you have a fairly large, heavy motorhome towing a dinghy, so a stock engine is not going to be a hot rod pulling the hills. I suggest you try driving a similar motorhome for comparison. I have not tested the REACT unit, but Hypertech has been around for decades and has a good reputation. The Hypertech REACT requires no reflashing of the ECU and won’t leave a trace, so that subsequent Ford warranty coverage won’t be affected. Depending on the vehicle, it plugs in-line with the accelerator pedal harness and reinterprets the signal to the setting a user desires. It seems like a good match for your needs.

Dim Dash
Do you have any suggestions to increase dash lighting in a Forester Class C motorhome? The overhang makes it very difficult to see gauges and displays, such as mileage.
Harold Ratcliff | Edgewood, New Mexico

If the cabover body overhang shades the dash enough that you can’t see the instruments by day, you might need to just drive with your headlights or running lights on all the time so the instrument lights are on. It’s not a bad safety consideration. Depending on the make of cab and the model year, earlier models using conventional incandescent dash light bulbs can be brightened by using LED replacement bulbs. Without having the year and model, it’s difficult to make other recommendations. I’d like to hear from our readers on possible solutions.

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 has been an RV, camping and travel enthusiast since he was a child.

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