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[TTC]

I retrofitted a standalone gauge cluster into my car. The only problem is my oem fuel sender uses the following ranges.

3Ω Full
32.5Ω Half Full
110Ω Full empty

These are my options. I was told to put a 180ohm resitor in parallel and that should get me close using VDO dip. Is there another solution?

VDO Lever-Arm Fuel Sender (3Ω Empty-180Ω Full)
VDO Dip-Pipe Fuel Sender (70Ω Empty -2Ω Full)
Capacitive Type tube sensor ( 10Ω Empty-180Ω Full)
General 1 – (240Ω Empty to 33Ω Full)
General 2 – (132Ω Empty to 52Ω Full)

Those are the only settings I can set in the software.

[pitobread]

VDO Dip-Pipe Fuel Sender (70Ω Empty -2Ω Full)  That is your closest option Tom, if you meter it right now with the 180ohm resistor what are you getting for values?

[TTC]

Can't really Meyer it since its on the tank.y spare gives no reading. It's rusty and fucked

[DSMR]

The problem with using resistors is that the slope of the resistances is preset thing. You can voltage divide all you want, but that will not change the slope.

Voltage divider : Vo = Vi (R2/(R1 +R2)) = Vi (1/((R1/R2) + 1))  Take the limit of R2 -> Inf and R2 -> 0. That will give you your V/R characteristic graph. That slope is a constant thing.

My advice, 2 options:

Use a potentiometer and get it dialed in for the empty setting (so you not sitting around with your dick in your hand on the side of the road)

Get fancy and use a microcontroller to do all the calculations. It would be a simple project for a modern uC. Use the controller to drive the voltages into your gauge cluster (Will require add'l hardware but it is easy and well documented).

Edit: Better yet, if you go the controller route, just get a display and have it work off of that. That would look much better and be really easy to do. You can go 7 segment, LCD, ect. 

[t_cel_t]

or you could get one of those tiny stepper motors, some cheap uc, and 3 lines of code and just run the needle that way

[SgtB]

You could use an 8pin uC to read the sender on an ADC, and then translate it with either PWM or a digital pot.

[HiProfile]

You could use an 8pin uC to read the sender on an ADC, and then translate it with either PWM or a digital pot.

60 seconds with picaxe:

readadc b.1,var1
let var2 = var1 x [formula if not linear]
pwmout C.5, 99, var2
pause 1000

Then it would need about 13 compnents including the chip, 7 if you feed it 5v directly.