Odd fuel gauge?

[HD7]

Right so replaced my clocks as that was the problem after I tried changing the sender. Now it is reading about a quarter above what it should. I know cos I ran out of fuel today :wall:

Is my fuel sender knackered or is there a way of calibrating it or something?

[D4NNY-801]

Fuel senda nackered/float stuck

[citroensaxo]

Dear HD7,
Firstly HD7, did you fit a " new " fuel tank sender unit ? Or was it a " used/ secondhand one ?
Vince,

[HD7]

When my fuel gauge was doing the bouncing three times thing I tried splicing the wires to earth them and replacing the sender with a second hand one. So I've changed the clocks. I took the fuel sender back so its still my original one on the car.

[citroensaxo]

Dear HD7,
When you replaced your tank sender unit with the secondhand one, did you happen to notice whether it was the older " metal arm " type( with a seperate float ) or was the newer type " cylindrical type "( with the float located in the centre of the cylinder ) ?
Vince,

[HD7]

It has the float on the arm that pivots. Cheers

[citroensaxo]

Dear HD7,
Oh great news that then HD7, That type you can physically " adjust ", you just need to remove your tank sender unit from the tank, and then you can " gently " bend the " metal arm " by hand:y: you will need to bend the arm " down " ( to make the float sit lower in the tank ! ) The best place to bend the metal arm would be at the " part " where it is already " bent " If you understand what i mean:y:
hope this helps HD7,
vINCE,

[HD7]

Okay I'll have a look, thanks. Any idea how much to move it down by?

[stevo67]

Dear HD7,
Oh great news that then HD7, That type you can physically " adjust ", you just need to remove your tank sender unit from the tank, and then you can " gently " bend the " metal arm " by hand:y: you will need to bend the arm " down " ( to make the float sit lower in the tank ! ) The best place to bend the metal arm would be at the " part " where it is already " bent " If you understand what i mean:y:
hope this helps HD7,
vINCE,

Thats assuming that the float itself ie the resistor isn`t faulty mate.:drink:

[HD7]

Surely if the resistor (wherever it may be) has gone then it would read nothing?
It was reading just above the red when i ran out, when i put £20 in it was reading just above 3/4 so I think its constantly above by about a quarter, not intermittent if you see what I mean?

[citroensaxo]

Dear HD7,
One question I need to ask, is how many electrical wires do you have on your fuel tank sender unit ? If it a " older " set up it may only have " one " wire going to it. If it as I suspect " two " wires or more, then that will be just great:y:
The " first " thing you need to do now HD7, is a " check ", what you need to do is to remove your tank sender unit ( complete with its electrical plug still connected ) And then you will need to switch your ignition on at the key ( but don,t start the engine ! ) The next thing you " check " is that your " low fuel warning light ) on the dashboard is working correctly ( to do this you will need to " look " at the warning light, whilst you " move " the " metal arm " on your fuel tank sender unit, ( it should, all things being correct ) you should be able to see your fuel gauge on the dashboard ( moving from " empty " right through to " full ":y: The one thing we are " focuing " on, is the functioning of the " low fuel warning light, as this is a " base " for our adjustments:y:
The second thing you need to do, is mechanical item, what you need to do is to get either 2 pairs of " flat " nosed pliers or a pair of pliers and a pair or small mole grips etc. and bend your " metal arm " on your tank sender unit,
you will to only move it, just enough to make " float " on your sender unit, sit about 1 cm ( so that it will sit " 1 cm lower " in your petrol tank:y:
It maybe a bit of " trial and error " at first, but if your " fuel gauge " on your dashboard, is still looks to be " still " reading a bit " high " Then bend your " metal arm " another 1 cm, and see how that goes.
I hope this helps,
Vince,

[HD7]

Okay going to go and have a look now, thanks!

And it has 5 wires going to it

[MartinObviously]

your replacement sender, was from a 3 plug ECU model and your dash is still digital?

There is a case if you fit an old type sender, to the newer clocks it reads too high as it operates slightly differently.

[MartinObviously]

Dear HD7,
One question I need to ask, is how many electrical wires do you have on your fuel tank sender unit ? If it a " older " set up it may only have " one " wire going to it. If it as I suspect " two " wires or more, then that will be just great:y:
The " first " thing you need to do now HD7, is a " check ", what you need to do is to remove your tank sender unit ( complete with its electrical plug still connected ) And then you will need to switch your ignition on at the key ( but don,t start the engine ! ) The next thing you " check " is that your " low fuel warning light ) on the dashboard is working correctly ( to do this you will need to " look " at the warning light, whilst you " move " the " metal arm " on your fuel tank sender unit, ( it should, all things being correct ) you should be able to see your fuel gauge on the dashboard ( moving from " empty " right through to " full ":y: The one thing we are " focuing " on, is the functioning of the " low fuel warning light, as this is a " base " for our adjustments:y:
The second thing you need to do, is mechanical item, what you need to do is to get either 2 pairs of " flat " nosed pliers or a pair of pliers and a pair or small mole grips etc. and bend your " metal arm " on your tank sender unit,
you will to only move it, just enough to make " float " on your sender unit, sit about 1 cm ( so that it will sit " 1 cm lower " in your petrol tank:y:
It maybe a bit of " trial and error " at first, but if your " fuel gauge " on your dashboard, is still looks to be " still " reading a bit " high " Then bend your " metal arm " another 1 cm, and see how that goes.
I hope this helps,
Vince,

Go and " not " type " like " this. it makes your posts really hard to follow and makes you look like an idiot. :hug:

[HD7]

Turns out the plug has 4 wires, but another terminal (for 5).

When the float is at the bottom, the fuel gauge doesn't read empty, it reads slightly above (so where I ran out of fuel!).

I'm being misunderstood, I HAVEN'T CHANGED THE FUEL SENDER.

So is there any way that I can fix this or is it time for a new sender? It works but just reads slightly above.

[MartinObviously]

HD7

500 ohms across your sender is going on for an empty tank

70 ohms or less is going on for a full tank.

[HD7]

I'm not sure which pins to take a reading across? My sender is reading correctly it seems, just that its a little above.

[MartinObviously]

Cheat the system, and fit a low value resistor in series ;)

Use a variable resistor to set the guage where you want it based on the amount of fuel you have, measure the resistance you've fitted then fit permanent resistance of that value.

these gauges aren't accurate, you're better off working out what mpg you manage then looking at your trip.

[HD7]

Yeah but realistically, isn't that tecnically bodging it.

Is there a possibility that theres a fault with the petrol gauge itself?

[MartinObviously]

Yeah but realistically, isn't that tecnically bodging it.

Is there a possibility that theres a fault with the petrol gauge itself?

It'a accurate bodging.

Yeah, I'm sure there's an electrical damper on the dials to stop the needle flickering. I guess if it failed it could cause a higher voltage to go to the guage and give you a higher reading?

You said you've changed your clocks though already?

[HD7]

Yeah but who's to say these aren't knackered too as my temp gauge is playing up! Would a new fuel sender cure this problem?

[lewismonteith]

Have you plugged mk2 dials into a mk1?

[HD7]

Nope, mk2 dials into a mk2. Replaced what was there with the same.

[HD7]

Anyone?