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Author Topic: fuel gauge  (Read 809 times)

mellis

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fuel gauge
« on: November 28, 2017, 05:46:06 PM »
 ok i have  a situation ,,, my gas gauge seems to just change as you drive  from  3/4  to 1/2  and then back up as i drive ,,, first thinking  hills or  things is changing it ,,,, then as i am sitting  level it went to  1/4  then to empty,,,,   today as i started engine it went to empty,  and stand that way while i drove about  40 miles , then it just went to  1/2,,  i stop  for gas to fill it and see what it would do and i  only got  20 gallons in the tank  ,,, i have a  75 gallon tank ,,,  when i started it it went to full  then as i drove it dropped again to  1/2,,, Do you think it is a sensor,,  or what else could it be ,,,,  it is a  2007  monaco cayman 36 ft   A- class 

thank you

HueyPilotVN

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Re: fuel gauge
« Reply #1 on: November 28, 2017, 05:57:42 PM »
I think that the problem is variable resistance.  The gauge is activated by the changing resistance from the sending unit going up and down and varying the amount of resistance.

It is probably the sending unit, however anything that changes the resistance including the connections, wiring, or gauge could be the problem.

Just my opinion.
Bill Waugh
40' Country Coach DP
2 Jeep Commanders
Mustang Bracket Race Car
Retired from the road to Lake Havasu after 35 years on the road

gwcowgill

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  • Retired USAF, Retired Auto Instructor Dade Cty Sch
Re: fuel gauge
« Reply #2 on: November 28, 2017, 06:01:54 PM »
Check your ground and connections in the circuit.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

Gary RV_Wizard

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Re: fuel gauge
« Reply #3 on: November 28, 2017, 06:33:51 PM »
Agree with both suggestions above. Could be the sending unit in the fuel tank are an electrical problem in the dash (ground or power).
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

mellis

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Re: fuel gauge
« Reply #4 on: November 29, 2017, 11:18:09 AM »
all the other gauges work  good,,,  so i guess the sending unit is inside the tank ,,,  does that mean i would have to drop the tank to get to it ,,,,  that would suck ,,,,, 

Gary RV_Wizard

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Re: fuel gauge
« Reply #5 on: November 29, 2017, 02:43:42 PM »
Probably.

I would not conclude there are no dashboard ground or power problems simply because other gauges work. There are a ton of wires back there, and each electrical item needs a solid ground to perform reliably.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

mellis

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Re: fuel gauge
« Reply #6 on: November 29, 2017, 03:21:40 PM »
thank you  all,,,,  should be fun trying to get the dash board gauges out to check ,,, yipppeeeeeee,,, lol   

gwcowgill

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Re: fuel gauge
« Reply #7 on: November 29, 2017, 03:47:12 PM »
Don't pull the gauges yet. Go to the tank, there should be a ground wire going from the sending unit to a frame ground. Check that connection  and I mean take the wire loose from the frame and clean the frame and the connector where it makes contact before you start disconnecting other things. There is a signal that goes through the gauge to the sending unit to ground. If that ground is bad you will see readings all over the scale and on older vehicles, it is quite common to see that ground bad.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

gwcowgill

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  • Retired USAF, Retired Auto Instructor Dade Cty Sch
Re: fuel gauge
« Reply #8 on: November 29, 2017, 03:51:48 PM »
BTW, when you disconnect the ground wire, the gauge should read empty.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

mellis

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Re: fuel gauge
« Reply #9 on: November 30, 2017, 02:44:35 PM »
thank you so much that was very helpful   

William52

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Re: fuel gauge
« Reply #10 on: November 30, 2017, 06:31:56 PM »
ok i have  a situation ,,, my gas gauge seems to just change as you drive  from  3/4  to 1/2  and then back up as i drive ,,, first thinking  hills or  things is changing it ,,,, then as i am sitting  level it went to  1/4  then to empty,,,,   today as i started engine it went to empty,  and stand that way while i drove about  40 miles , then it just went to  1/2,,  i stop  for gas to fill it and see what it would do and i  only got  20 gallons in the tank  ,,, i have a  75 gallon tank ,,,  when i started it it went to full  then as i drove it dropped again to  1/2,,, Do you think it is a sensor,,  or what else could it be ,,,,  it is a  2007  monaco cayman 36 ft   A- class 

thank you
If you ground the sender signal wire should go to Full real quick, disconnected ground empty. Sender most likely  Replace all rubber hoses if you replace sender. Could be the float ?
2000 Pace Arrow M35N F53 V10 Ford  100,000 + miles purrs like a kitten. 2019 Cherokee Trailhawk, Roadmaster Falcon, RVI3 Brake

mellis

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Re: fuel gauge
« Reply #11 on: December 04, 2017, 04:56:07 PM »
i looked under my rv and it is  solid i can see the tanks but no wires , they must be  on top somewere , can not find the sender or  any grd wires   ,,,, 

gwcowgill

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  • Retired USAF, Retired Auto Instructor Dade Cty Sch
Re: fuel gauge
« Reply #12 on: December 05, 2017, 05:37:02 PM »
i looked under my rv and it is  solid i can see the tanks but no wires , they must be  on top somewere , can not find the sender or  any grd wires   ,,,,

The sending unit is on top of the tank with the wires coming in there. You may need to drop the tank to get to it. You might call Monaco to find out how to access it and the color coding for the wiring going to the tank.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

B737doc

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  • 1992 Challenger
Re: fuel gauge
« Reply #13 on: January 24, 2018, 03:27:03 PM »
The fuel gauge on my 1992 Challenger is stuck at 1/4 tank.  PO says he never used it.  He merely "calculated" the quantity by writing down the mileage after he filled the 60 gallon tank.   I have been out twice and have never came close to running out using the 5.1 mpg formula (that's fully loaded pulling a trailer with 2 motorcycles).  Piece of cake.
1976 BMW R90/6 "Airhead"
2005 Triumph Bonneville "America"
1992 Challenger Motorcoach