Project-Zero: ETB Fuel Level Sender and Gauge

 The Zero has been on stands for a few weeks while I work on small things.  Last time I updated here I was working on calibrating the Smiths fuel level sender to work with the AIM dash.

That didn’t go well.

Eventually I’ll revisit the notion of having the AIM display fuel level but for now I’m throwing an ETB Instruments sender and GT40 style gauge into a 3D printed pod sticky-taped to the dash. I went with ETB because their sender fit the bolt battery GBS use on their tank so it was easy.

The lever arm of the sender needed to be adjusted for length to keep it from hitting the sides or bottom of the tank. (There’s about 3/4” between the bottom of the float and tank at full droop.) This provides a bit of a buffer at ‘E’ which is good since the car’s tank realistically only holds 7.5 US gallons of fuel.

The gauge is wired to the send through the factory harness, not the AIM harness I built.  For simplicity I’m taking switched power and ground from the USB charger/voltmeter in the center console. The gauge pod is my own design that uses GoPro mounting hardware and 3M mounting tape to stick to the underside of the carbon fiber dashboard.  I didn’t bother wiring up the gauge illumination.

Anyway, I now have a working fuel level gauge which is honestly all that I care about while working out confidence in what kind of range I’m going to be able to get out of this car.

Project-Zero: Fuel Level Wonkiness

My first try at calibrating the fuel level sender in my car did not go well.

My calibration process kind of sucked, I can do much better. I spilled fuel, it wasn't a clean way to do thing. The next go of it I'll actually have a 1 gallon fuel jug and no-slosh funnel.

Not really happy with the fuel level sender I was gifted by a friend, I ordered a new sender/gauge kit from ETB Instruments in the UK. It gives me a known good starting point.

The new sensor should read:

• 260 ohms, empty ( 0.631v w/ 1.8K ohm pull-up )
• 20 ohms, full ( 0.055v w/ 1.8K ohm pull-up )

Which the simulations on EveryCircuit confirm.

GBS Zero Fuel Level Sender - EveryCircuit

Project-Zero: Fuel Level Sender to AIM Cable Build

I ordered the Zero without instrumentation, I'm using an AIM MXS. Fuel level will go to the MXS as an analog input.

This requires a cable with a pull-up resistor between +5v and the signal. (AIM have a good description of it in this PDF.)

I used a 1.8K ohm resistor for the pull-up.