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Topic: DP fuel gauge malfunction

Posted By: kenbrads on 09/20/09 08:28am

The last two times I have filled the tank, the fuel gauge only shows 3/4's full. Once I burn enough to get to the 3/4 level the gauge works normally.

Has anyone had this problem and were you able to fix it without having the gauge replaced?

Thanks for any information.

Ken Bradshaw 04 CC Allure

Posted By: Fishinghat on 09/20/09 08:54am

I remember at a seminar at a rally three Cummings technicians explained that they consider the motorhome instrument panel to be a "entertainment panel" since the gauges are frequently inaccurate. Since you're familiar with this abnormality, it shouldn't be a serious problem.

Holiday Rambler Navigator DP, Hummer, and Honda VT1100C Shadow

Posted By: Roadpilot on 09/20/09 04:19pm

I used to have 2004 Monaco Diplomat that had similar issues with the gas gauge. The problem was in the sender unit mounted on top of the tank, actually in a very accessible spot. If I recall there was at least 1 adjustment screw on the sender and I think 2 screws. It finally turned out thought they had installed the wrong sender when the chassis was built. In the Dip it was easy to change the sender. They didn't have to drop the tank or empty it.

Millennium Prevost 2018
2013 Chevy Avalanche Black Diamond
2013 Chevy Tahoe
HD 2015 Ultra Limited Low (Mine)
HD 2016 Triglide (DW)
Cruiser Caddie motorcycle lift and 24' Stacker

Posted By: petiredpete on 09/20/09 09:50am

my fuel gauge has an adjustment on the's a goofy thing as it senses the fuel level electronicly instead of a float...had to send it back to the mfg. in florida when i 1st. bought my coach (used), for calibration..had to partially remove 200 gallon diesel tank to remove sender...

Posted By: wolfe10 on 09/20/09 09:53am

Yes, some of the gauges have a tiny adjustment screw on the sender unit to calibrate FULL.

Contact your gauge manufacturer for correct procedure/contact CC for name of gauge manufacturer.

This is assuming all other gauges are reading normally. If more than one gauge is reading incorrectly, look for other problem at dashboard end.

Brett Wolfe
2003 Alpine 38'

FMCA Forum:

Diesel RV Club:

Posted By: jimhaz2402 on 09/20/09 10:08am

Just be real certain that you are FILLING the tank to where you can see it 'pool' in the fill tube. I had the same thing happen to me that you are experiencing when we got our '07 Phaeton. Now I dribble it in (totally disregard the 'click' on the pump lever as that means nothing!) until I see the fuel---not the foam---and the gauge goes right up to 'full' reading everytime.

Posted By: wolfe10 on 09/21/09 10:42am


Do you have both Demco gauges AND Demco SENDING UNIT?

Posted By: Boxer Lovers on 09/21/09 09:55am

My 98 CC has Demco guages and I have always had problems with the fuel guage reading correctly. Once full of fuel the guage may stay on full until I refuel using the trip meter, then it may read full or begin to reflect fuel usage down to about half full, which is really empty.

I've had it calibrated at a shop, but no change. I just rely on my trip meter and fill er up about every 600 miles or so. Gets 8 to 8.5 m.p.g., so its pretty fool proof and certainly less expensive than trouble shooting the darn thing for a fix.

Dave, Robin, and Buster the Boxer
2008 Beaver Contessa, 42, Caterpillar 425
Toad 2017 Ram 1500, Quad Cab, Limited, M&G brake, Blue Ox.

Posted By: wolfe10 on 09/20/09 04:38pm

If you have the Centroid gauge like ours, indeed there are two tiny adjustment screws. One is sealed and SHOULD NOT BE ADJUSTED.

The other is the "full tank" adjustment screw. Have adjusted several. With tank full (proven full as suggested by Jim) you make TINY adjustments while someone else monitors gauge readings.

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