Fuel Sender Dampin
Discussion
Hi all,
would anyone be able to explain the damping system on the fuel tank to me?
All of a sudden my gauge has large and very quick swings of level when cornering/going up hill whereas before it was always smooth and very slight.
Is is mechanical or electrical?
Is it an easy fix?
Many thanks
Ryan
would anyone be able to explain the damping system on the fuel tank to me?
All of a sudden my gauge has large and very quick swings of level when cornering/going up hill whereas before it was always smooth and very slight.
Is is mechanical or electrical?
Is it an easy fix?
Many thanks
Ryan
Because its such a simple job I would start by taking the sender unit out and check its free to move through the full arc.
You can also turn the float around so the longer end is facing towards the rear of the car, with the standard setup the longer end can foul on the tank wall causing erratic readings.
The sender operates using a float at one end of a thin wire arm commonly known as the wand, this moves a commutator finger over the potentiometer windings at the other end.
When you remove the sender (which is an easy 5 minute job) you will see that there is no damping as such, it is completely free to move throughout it's full articulation.
There is a tiny spring that acts on the commutator finger, but it's job is more about ensuring the finger is in constant contact with the potentiometer windings rather than providing any significant damping effect.
I expect the true fuel sender damping effect on cornering and changes from horizontal are taken care of by the internal tank baffles.
The baffles are there to limit the fuel surging within the tank; if no baffles were fitted then the fuel would move quite a bit and the sender would give erratic readings (& some interesting handling effects).
So perhaps the answer to your problem is not the sender at all.
If the sender checks out OK my guess would be one or more of the internal tank baffles has come free.
I understand it's not that uncommon for the baffles to become detached in a Chimaera petrol tank, this would be made more likely if you have ever had a vacuum lock in the tank.
For example if the fuel filler isn't venting correctly the fuel pump can suck the tank distorting it enough to dislodge a baffle.
Good luck, & let us all know how you get on.
You can also turn the float around so the longer end is facing towards the rear of the car, with the standard setup the longer end can foul on the tank wall causing erratic readings.
The sender operates using a float at one end of a thin wire arm commonly known as the wand, this moves a commutator finger over the potentiometer windings at the other end.
When you remove the sender (which is an easy 5 minute job) you will see that there is no damping as such, it is completely free to move throughout it's full articulation.
There is a tiny spring that acts on the commutator finger, but it's job is more about ensuring the finger is in constant contact with the potentiometer windings rather than providing any significant damping effect.
I expect the true fuel sender damping effect on cornering and changes from horizontal are taken care of by the internal tank baffles.
The baffles are there to limit the fuel surging within the tank; if no baffles were fitted then the fuel would move quite a bit and the sender would give erratic readings (& some interesting handling effects).
So perhaps the answer to your problem is not the sender at all.
If the sender checks out OK my guess would be one or more of the internal tank baffles has come free.
I understand it's not that uncommon for the baffles to become detached in a Chimaera petrol tank, this would be made more likely if you have ever had a vacuum lock in the tank.
For example if the fuel filler isn't venting correctly the fuel pump can suck the tank distorting it enough to dislodge a baffle.
Good luck, & let us all know how you get on.
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