Adjusting the fuel sender float

[greg g]

Put in a new fuel gauge sender (2 wire) gauge works but is not accurate at the bottom end. Quarter tank reading has only 2 gallons.  Based on 17 gallon capacity, it should have give or take 4 gallons. I need to bend the float rod, I'm thinking l need to bend it up to have it more accurately indicate the lower quantity.  Is my guess a good one?

[John Fleming]

Greg I have had the same problem after replacing fuel sender on my P15 . My fuel tank bent up a little at bottom .  I hope another member can answer your question .

[Silverdome]

Makes sense to me.

[Plymouthy Adams]

measure from the flange to bottom of the tank....also verify your length to any inner baffle so to avoid dragging.  Remove the float assembly and balance the gauge reading...keep 1/2 as close to 1/2 as possible as this will be your ho/low reference if the sender resistor winding is a bit off linearity. Keep in mind the float itself will need be accounted for.

[PT81Jan]

9 hours ago, greg g said:

Put in a new fuel gauge sender (2 wire) gauge works but is not accurate at the bottom end. Quarter tank reading has only 2 gallons.  Based on 17 gallon capacity, it should have give or take 4 gallons. I need to bend the float rod, I'm thinking l need to bend it up to have it more accurately indicate the lower quantity.  Is my guess a good one?

 

5 hours ago, John Fleming said:

Greg I have had the same problem after replacing fuel sender on my P15 . My fuel tank bent up a little at bottom .  I hope another member can answer your question .

 

I assume both your top / full reading is correct (A) ? If so, bending the rod might help to correct the low level reading but would also have effect on the top level reading (B).

More important probably is the low level reading. If you can live with a solala top reading then bending can be a solution.

To get a correct reading top and low level the length of the rod also has to be considered (C).

I made a sketch with the influence of bending and rod length adjustment. I hope it is understandable.

For the adjustment of my sending unit I took a wood board, painted a 1:1 side view of the fuel tank to it and laid the unit down to it in the position where it is mounted to the tank. Hooked  then the instrument and a battery. So it easily was possible to simulate the fuel level by moving the rod and determine the correct rod length. Sorry no picture of this.

Do it yourself rod, if of interest -> http://p15-d24.com/topic/42339-plan-b-–-what-if-parts-are-not-or-difficult-to-get/  #23

 

Edited July 31, 2018 by PT81Jan

[bluefoxamazone]

mine is reading 3/4 full when completely full... can this be adjusted or is this an electric problem?

 

grtz,

[PT81Jan]

6 minutes ago, bluefoxamazone said:

mine is reading 3/4 full when completely full... can this be adjusted or is this an electric problem?

 

grtz,

 

If you have all the original equipment it most likely is not an electrical problem.

Then the adjustment can be done with a rod correction. But before I would check if the float is leaky and therefore doesn`t float on the correct level !

If you have an universal sending unit it is likely its resistor does have another resistance.

If you have another instrument it also is likely it doesn`t match to the resistant of the sending unit.

[Plymouthy Adams]

1 hour ago, bluefoxamazone said:

mine is reading 3/4 full when completely full... can this be adjusted or is this an electric problem?

 

grtz,

 

look at the slight kink in the arm in the above pictures to allow full deflection on the sender while offsetting the float a tad lower allowing the full upper swing

[Dodgeb4ya]

Too bad the offshore replacement units are not correctly  calibrated for our cars?

[greg g]

Well, I guess at fill-up time I will just add 255 miles to the odo reading and carry on. That should give a 20/25 mile reserve.