Petrol tank

[Road Runner]

My fuel tank is huge and must be a minimum of 50 gallon but i reckon higher around 90 gallons.

Anyway my fuel gauge has gone bonkers and operate at over full all the time and I seem to have a range between fills of 100 litres (23 gallons) and then it's showing signs of running out.

I ALWAYS absolutely brimmed it each time.

What can go wrong with a petrol tank?

 

[Lindy-C]

Duff sender unit perhaps?

 

[Tony Hunt]

"Theres a hole in my bucket dear liza dear liza theres a hole" Seriously Road Runner how much fuel are you putting in the tank when you brim it, surely thats the big question. If your only putting in 20 odd gallons then your fuel gauge is dicky. If your putting in 80 -90 gallons then you have a serious problem that needs investigating

 

[Road Runner]

I am getting only a 100 litres in which ain't a great deal for an RV.

That all it will take between full to showing running out sign and this is not bothering with the gauge oh:

 

[Geoff]

Has this always been like this since you've had it?

If so it could be an incorrect sender unit, as most also have the pickup pipe as part of this unit, it (the pickup pipe) may only be reaching partway into the tank.

Regards Geoff.

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[pappajohn]

hi,
probably a bad earth connection at the sender unit/tank.
get someone to hold a piece of wire on the tank sender housing(clean an area with wire wool first) and to a good, clean chassis earth and check the guage then.
most vehicle electrical faults are down to poor earthing and the sender unit also needs a good earth.

john.

 

[Road Runner]

Forget the petrol gauge I can only get in and use 100 litres into a tank thats far larger.

Can a sender affect this?

 

[Geoff]

Can a sender affect this?

See my previous post

(Quote)If so it could be an incorrect sender unit, as most also have the pickup pipe as part of this unit, it (the pickup pipe) may only be reaching partway into the tank. (Quote)

I.E. If the tank is 18" deep but the pickup pipe only reaches in 6" you would only be able to use 1/3 of your tank capacity.

Bent or broken pickup pipe could also cause this. Have also known rust holes to cause this, but I think yours is some what too new for this.

Regards Geoff.

 

[pappajohn]

as geoff said it could be the pickup pipe.
it could have broken off due to metal fatigue/vibration and isnt reaching the tank bottom but that wont explain the guage showing constant full.
reckon you're gonna have to take the sender out for a looksee if the pipes broken off and check for broken wiring.

john.

 

[Geo]

John have you checked shape of tank has it collapsed ie incorrect or non vented fule cap can cause vacume and collaps a tank, but RV tanks are made of much thicker than normal steel so maybe not, another stupid suggestion you do know fuel pumps cut off at 100 ltrs full or not, dont you, and you have to hang up pump and start again to get more out of the pump mine holds 200ltrs and more
Geo
ps you then pay two seporate bills of a ???ltrs each if you get the drift

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[Road Runner]

John have you checked shape of tank has it collapsed ie incorrect or non vented fule cap can cause vacume and collaps a tank, but RV tanks are made of much thicker than normal steel so maybe not, another stupid suggestion you do know fuel pumps cut off at 100 ltrs full or not, dont you, and you have to hang up pump and start again to get more out of the pump mine holds 200ltrs and more
Geo
ps you then pay two seporate bills of a ???ltrs each if you get the drift

Yes earlier in it's life took nearer 200 litres so need it reset.

The tank is in good condition and looks tough and no way collapsed. Does a tank feed from the base or is there hoses into it that may have gone wonky?

 

[Geo]

If im reading you correctly john you are saying that the tank does hold 200 Lts and maybe more ,therefor it has indeed got that much fuel in but you can only use 100 ltrs of it becuse when it reads emty you fill up again you could use more if you wanted
you may then have just a faulty gauge
the guage is screwed up and next to usless for working out what fuel you really have so can be ignored
it may be working to the efect of showing full when it is full, and emty when its in fact half full, still you fill up when it reads emty and can only get 100 Ltrs in ie therefore it must be still half full when your filling it, you need a new sender or a dip stick to check out the therory, or run on an estimated mileage before filling up again, or run it right out and carry a gerry can, then you will know for sure
Geo

 

[Road Runner]

If im reading you correctly john you are saying that the tank does hold 200 Lts and maybe more ,therefor it has indeed got that much fuel in but you can only use 100 ltrs of it becuse when it reads emty you fill up again you could use more if you wanted
you may then have just a faulty gauge
the guage is screwed up and next to usless for working out what fuel you really have so can be ignored
it may be working to the efect of showing full when it is full, and emty when its in fact half full, still you fill up when it reads emty and can only get 100 Ltrs in ie therefore it must be still half full when your filling it, you need a new sender or a dip stick to check out the therory, or run on an estimated mileage before filling up again, or run it right out and carry a gerry can, then you will know for sure
Geo

No Geo its starting to peter out and so and urgent refuelling necessary so basically it allowing only 100 litres between fills ignoring the fuel gauge.

So it'e like only half the tank working and it seem the top half because i fill it and fill it to brim it with many clicks on the pump.

 

[Tony Hunt]

Is it petering out or are you bricking it because you think its gonna run out. I would put a couple of gallons in a spare tank and a funnel and run that son of a bitch till it runs out of gas or doesnt like Geo says. Then ring Linda up and get that new sender unit. You could also take it in to a garage if you cant tackle it yourself when you think its nearly empty and get them to drain the tank into drums and investigate the problem.

 

[Road Runner]

I am now carrying 2 X 25 litre cans full


Ta for all your advice everyone:thumb:

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[Stueysheep]

When it's petering out and the engine is telling you it's about to run out, can you tap knock on the tank with a spanner and "hear" if it's empty? It will sound quite different empty, half full and full... Cheers

 

[Geo]

My next best guess is that the pick up pipe has a hole in half way down then John, if its part of the sender unit that shoud fix it if its not then you need a new pick up pipe as well
Geo

 

[Road Runner]

After New Years meet going to have the tank dropped out and examined.

Decide what to do then as i am defiantly going gas in the New Year (bet I don't keep it long thenoh:)

Now looking for a firm of fitters who will do me a good price and job

 

[TestPoster]

Just a quick thought John????
Has your tank got water in it? I know it is remote but maybe you have picked up some duff petrol somewhere or got huge amounts of condensate into it....
Maybe try to get a tube down into the tank and pull up from the bottom and see what comes out? Or have you local garage do it.
Having water in the tank will show as a volume for the guage but the motor will not run on it......
Just a thought

Keith

 

[olley]

Hi Keith not likely as the petrol would float on top of the water, and his dip tube would draw the water up, then as you say it wouldn't run.

Olley

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[Road Runner]

My bus did a hole lot of standing as stunningly low miles which every mechanic who works on her agrees are real plus the interior measure up to this usage too!

4100 miles when I bought her.