Thread: tdci fuel sender resistance range

Righteo,
So it took me a few weeks to use half a tank and make the measurements.
So this is for a 2010 2.4L tdci 130 defender.

Tank Full - 8 Ohm
Tank half - 50 Ohm
Tank empty fuel light just on 62L to fill - 194 Ohm

So possible VDO options
220.003 - 10 to 180 Ohm range
Or
A2C59510171 - 3 to 180 Ohm range

Neither perfect but close enough

Steve

If you use the 3 - 180 ohm unit you can add a series resistor to the sender wire to fine tune the reading, the value depending on whether the full reading or the empty reading is most important to you.

Good thinking beeutey
On my factory gauge it was reading above F at 8 Ohm
And about 1/8 tank at 194 Ohm with fuel light on

Fuel light and warning chime must be a function of resistance as there are only two wires from sender to dash.

I'm guessing the fuel light comes on at say 193 Ohm

So putting a 15 Ohm resistor into the VDO line will ensure the light will come on for the added tank in the last litre or so of capacity ... It might read a touch under full

But to check I'll take a reading when needle on the F

Anyways ramble finished

Steve

Actually I completely stuffed that up. Adding resistance will only make the problem worse. What you need is the 10 - 180 gauge and put a 2200 ohm resistor across the tank sender. The way to calculate two parallel resistances is:

R = 1/( (1/R1) + (1/R2) )

So using 194 ohms and 2200 ohms gives a combined empty resistance of 178 ohms, ideal for the gauge. In theory you could also add a 2 ohm resistor in series but that might be splitting hairs.

So I just had another measure 75km on from "full" tank and gauge is a smidge above full on the Gauge - resistance is 13 ohm

So my reckoning is I need a sender which runs from 15 Ohm full to 195 Ohm empty

So as resistance in series is added surely running the VDO 3-180 ohm sender with a 15 ohm resistor on one leg will give me a pretty accurate factory gauge ?

Let's put it this way I just ordered the A2C59510171 and seems I can find an 18 Ohm resistor ... Should be close enough

Steve

Originally Posted by roverrescue

So I just had another measure 75km on from "full" tank and gauge is a smidge above full on the Gauge - resistance is 13 ohm

So my reckoning is I need a sender which runs from 15 Ohm full to 195 Ohm empty

So as resistance in series is added surely running the VDO 3-180 ohm sender with a 15 ohm resistor on one leg will give me a pretty accurate factory gauge ?

Let's put it this way I just ordered the A2C59510171 and seems I can find an 18 Ohm resistor ... Should be close enough

Steve

You're right of course, I swapped the gauge and sender in my mind. Didn't reread your original post, you see.

Have another gin bee
Will make everything bettererererererer

S

Just remember the puma does the anti running out of fuel thing. From memory >6% it induces a misfire, >3% turns the engine off. So you'll need to be careful if you want to get the most out of your tank.

Cheers,