Fuel Gauge Questions

Topic: Fuel Gauge Questions (Read 1345 times) previous topic - next topic

Fuel Gauge Questions

November 27, 2017, 11:33:44 am

I have seen several post on here that the fuel gauge is not very accurate?

The gauge on the one I am getting says ½ full but I am a bit hesitant to trust it.

Can the fuel level be checked the old fashion way using a hardwood stick, from the angle I am not sure it will go in and give a accurate reading.

I have some Bulkhead work coming soon so I really dont want to fill the tank just yet.

Thanks

Re: Fuel Gauge Questions

Reply #1 – November 27, 2017, 11:37:08 am

Please add your coach info to your profile,

Re: Fuel Gauge Questions

Reply #2 – November 27, 2017, 11:38:30 am

Sure, you can dip the tank.

There is some adjustment in the sender unit (tiny screw) if it needs to be calibrated. Most are Centroid brand.

Re: Fuel Gauge Questions

Reply #3 – November 27, 2017, 11:40:36 am

Quote from: Tim Fiedler – November 27, 2017, 11:37:08 am

Please add your coach info to your profile,

There you go, I go close on it tomorrow then probably pick it up next week.

Re: Fuel Gauge Questions

Reply #4 – November 27, 2017, 11:42:45 am

Quote from: wolfe10 – November 27, 2017, 11:38:30 am

Sure, you can dip the tank.

There is some adjustment in the sender unit (tiny screw) if it needs to be calibrated. Most are Centroid brand.

Thanks Brett, I will measure it tomorrow and see how long it needs to be. I have a nice strip of hard maple that would work just fine.

I cant get it into MOT until 1/4/18

Re: Fuel Gauge Questions

Reply #5 – November 27, 2017, 12:34:44 pm

Ours doesn't read the top 1/4 or the bottom 1/4. So 1/2 tank is accurate but it doesn't come off full until 1/4 is gone and it shows empty with 1/4 tank remaining. I wonder how that adjustment works ?

I start looking for fuel between 800 and 900 miles on a tank.

Re: Fuel Gauge Questions

Reply #6 – November 27, 2017, 01:02:40 pm

My dash gauge moves between 3/8 and 9/16. At 3/8 the PO said we had 70 gal left. If the tank is full then for us, 800 miles puts us close to 1/2 and like Bob, I am looking for fuel. Normally I rarely get below 1/2 but if we are here to there cross country I run between 80 and 160 gallons, get fuel every other day. (We are not driving much more than 350 miles per day) That is an average of 500 lb that we are just not hauling around.

My VMSpc does an accurate job of keeping track of fuel used by the engine. If it says I need 100 gallons to fill it I will add about +/-4% of that. Some of that is me filling the tank consistently.

Re: Fuel Gauge Questions

Reply #7 – November 27, 2017, 01:16:03 pm

A piece of stiff wire like a coat hanger would make a good dip gauge. It can be bent to any shape needed and much easier to clean than wood.

Re: Fuel Gauge Questions

Reply #8 – November 27, 2017, 03:40:45 pm

On tanks that are uniform in L/W/H, you can easily figure out how many gallons per inch. Our U300 tank is exactly one inch for 6 gallons. Easy dip stick from tape measure, wire, string with a small float tied to an end.

I had an idea to use my IR gun to shoot the side of the tank. Where the reading changes is the level. Easier with low tank and hot fuel. A dip stick could be calibrated by adding five gallons at a time to the tank. Easy to interpolate.

Electronic engines will give an exact reading if you have a reader for the number of gallons the main engine uses after you fill. Not including AH or generator.

If you have an ECU (engine computer) that uses diesel to cool it, good to keep the tank toward the top or install a fuel line cooler/heat exchanger. Some fuel injection pumps don't like hot fuel. Our tanks are inboard so get almost zero cooling from airflow while going down the road.

Pierce

Re: Fuel Gauge Questions

Reply #9 – November 27, 2017, 03:59:19 pm

Thanks guy, I grew up on old old tractors that did not have fuel gauges so you always checked the level with wooden sticks we carried on all the tractors and checked fuel every time you stopped "LOL"

I am not ready to fill it until I figure out if it will have to come out for repairs.

Here is a article on some ways to set fuel gauges Beamalarm

Re: Fuel Gauge Questions

Reply #10 – November 27, 2017, 06:17:37 pm

I use a wooden yard stick from the local hardware store and cut it at 28-1/2" long.
Use it to verify the dash gauge on ocassion.

Re: Fuel Gauge Questions

Reply #11 – November 27, 2017, 06:59:15 pm

My fuel gauge is very accurate since I cleaned the contacts on the sender and calibrated it several times when empty and when full. Others have reported that cleaning the contacts did not make their gauge accurate.

I use an 8 inch long aluminum flat bar with marks on it to check fuel level when less than 25 gallons.

I also use the Silverleaf "fuel used" by resetting the "Auxiliary Trip" when refuelling.

Re: Fuel Gauge Questions

Reply #12 – November 27, 2017, 08:50:47 pm

Cleaning the contacts on my sender did not solve my fuel gauge error. I did have some success with giving the sender unit a bump with a hammer handle.

Don't hit too hard.

Re: Fuel Gauge Questions

Reply #13 – November 27, 2017, 08:59:32 pm

Mine wouldn't stay adjusted either so I ordered a new sending unit from foretravel. Perfect now.. self calibrating.

Re: Fuel Gauge Questions

Reply #14 – November 27, 2017, 09:00:34 pm

Ahh old school, if it doesn't work get a bigger hammer "LOL"

I will work at it to see just how it reads

Thanks

Re: Fuel Gauge Questions

Reply #15 – November 27, 2017, 09:01:38 pm

Quote from: DavidS – November 27, 2017, 08:59:32 pm

Mine wouldn't stay adjusted either so I ordered a new sending unit from foretravel. Perfect now.. self calibrating.

Thanks, that one article I read mentioned those but it did not indicate that the author had used one yet.

Re: Fuel Gauge Questions

Reply #16 – November 27, 2017, 09:14:15 pm

Quote from: DavidS – November 27, 2017, 08:59:32 pm

Mine wouldn't stay adjusted either so I ordered a new sending unit from foretravel. Perfect now.. self calibrating.

Yep, I did the same thing two years ago..... been working fine since, I occasionally check the level with the yardstick just cause
I'm "old "School"..............

Re: Fuel Gauge Questions

Reply #17 – November 27, 2017, 09:14:51 pm

Eight months ago I tried cleaning my fuel tank sender - did not help - still; erratic at the top end of the dash gauge. I suspect the adjustment pots of the sensor were at fault. Solution was to replace the tank sensor with a new elf-adjusting one from Foretravel. Problem solved though the dash gauge still reads way over full when the tank is really full .
Jim

2002 U320

Re: Fuel Gauge Questions

Reply #18 – November 28, 2017, 04:00:50 am

The end of Aug. (I purchased the rv in May of 2017) I finished a 2,500 mile trip from Eugene, OR to LAX back up to Portland and back to Eugene, OR. Several times now I've filled the tank at 1/2 full on the gauge and it took 75 gallons (150 gal tank). I understand your desire to not fill it until you find out if it needs to come out to repair and yes as Pierce says, it will be easy to check. Stll my advice to you is if your gauge is reading 1/2 full, depending how far your have to drive, fill it up, check your tank size, and you will know if at least at that point if it is reading accurately. After the trip I replaced all the fuel lines to gen and engine, which required emptying the tanks, checked the gauge as I refilled, all appeared accurate. I also cleaned the two wire connecting terminals to the gauge, as that often is a cause for a bad reading. It was not hard emptying the tank which was over 1/2 full. I bought three used racing fuel 50 gal drums for I believe $30-$35 each from a local fuel and oil distributor, they bought them back when I was finished for $15 each. I used the following fuel transfer pump to transfer. I purchased it at Harbor Freight and added a longer siphon hose to make it easier to transfer. I now have it to sell. 12V Diesel Fuel Transfer Pump RV Truck or Car - auto parts - by owner -...

Re: Fuel Gauge Questions

Reply #19 – November 28, 2017, 08:25:27 am

My results are like Jim"s. I adjusted the oem sender repeatedly but it was not consistent. The Foretravel Centroid self adjusting unit fixed the issue. Like Jim's mine reads over full on the gauge.

I,do tip the coach up on the passenger side during fueling and only fill from that side to fully fill the tank.

Gauge yesterday said 5/8ths and the coach took 91 gallons out of 192 gallon rated capacity.

Someone posted Foretravel has a different replacement sender than the self adjusting Centroid unit Jim and I purchased.

Re: Fuel Gauge Questions

Reply #20 – December 06, 2017, 02:13:36 pm

Great topic. Thanks, folks. I, too, have had difficulties with diesel tank reading and appreciate ideas expressed in response to this topic. Only time I can rely on my gauge is when I fill up.

Then it drops, at different rates ?, as diesel is used, hanging about 1/2 tank, sometimes a little lower. Consequently, when we get in RV for a trip, if not filled up entering storage, I am nervous until I fill up. Have used Gas Buddy in past, but recently - since we now will be towing - got Pilot Flying J account and will plot those locations

or other truck stops because of extra room (and don't tell DW, but I like the Cinnabons at Pilot

)

When in shop recently for other work, I asked that they check the gauge AND the sending unit. Response was that gauge was accurate but they could not check Sending Unit

. Just bought VMS from Roger and expect to use that, and a "stick" or coat hanger to "calibrate" gauge. Appreciate info on "new" self calibrating sending unit and I may have FOT or MOT install one to see if this resolves issue.

Re: Fuel Gauge Questions

Reply #21 – December 06, 2017, 07:59:57 pm

I keep my driver's information center set to always show the percent fuel remaining. It always agrees with the dash gauge, and I believe both use the tank sender. Whenever I fill up, I calculate the gallons used (if the tank is 30% full, fuel used would be 70% of 180 gallons, or 126 gallons. When I drop off my credit card at the gas station cashier, I tell them how much to charge the card based on that number and the current price. It is always spot on accurate.

Re: Fuel Gauge Questions

Reply #22 – December 06, 2017, 08:38:35 pm

Thanks Tom, I will keep a eye on it that way and see how it works with my gauge.

Affiliate Notice