about fuel level gauge

[davide30]

i want to know what you guys do when you keep the oem fuel tank and level sensor when we remove the oem cluster to put like AIM or stack cluster.
because the OHMs range of the sensor does'nt match with the after market fuel level gauge., if somebody could help me ill appreciate .


thx
dave

[thejlevie]

If the dash doesn't allow custom programming of the fuel level input, it would seem to me to be necessary to replace the OE level sensors with ones compatible with your dash.

[txse46m3]

I think I recall that BW has a solution for this (I might have it backwards...it might be for fuel cells and stock clusters). Worth a call.

[eye145]

Put the stack / aim in front of the cluster, leave a little room to the left to see the oe fuel guage. I saw it done in another thread but cant seem to find it again, but did run across this: gl hope this helps a little.
http://forums.bimmerforums.com/forum...ght=fuel+guage

[davide30]

thank you to all , but i found the spec , you will understand the problem now
empty tank 70 ohm and full tank 394 ohm. that why its so dificult to find a gauge in this range of operation.

let me know .
thx Dave

[osborni]

Assuming you are using a digital dash that is programmable and has analog inputs, you can use a pull up resistor to convert the tank sender resistance to a voltage. Then calibrate the fuel level to the voltage from the "new" level sender so you have an actual fill level.

[jjvincent]

For the AIM dash, it uses the BMW_Mini template. At this point, you'll have to wait until AIM comes up with a template for the MS43.0 or MS45.1 DME. I've already contacted them on this and they are working on it. At this point, a full tank will read around 56 liters. When it gets around empty, it's quite accurate. For example, at the end of Homestead my car registered 2.75 liters on the dash. When I pumped the tank, it was 2.65 liters. I do suggest keeping the stock dash and mounting the AIM in front of it.

One other thing you might find out, is that the water temp will not register correctly. On the 330, it's 20 deg too hot, on the Z4, it's correct.

[davide30]

re :jjvincent

i have a e46 but running complete engine mangement from e36 obd1, and that why i dont have the e46 cluster because i remove all the computer from it.

re:osborni
that true could be a solution i just have to check if its possible.
ill let you know
thx

[Naka]

Assuming you are using a digital dash that is programmable and has analog inputs, you can use a pull up resistor to convert the tank sender resistance to a voltage. Then calibrate the fuel level to the voltage from the "new" level sender so you have an actual fill level.

Mmmmmm......My ignorance is embarrasing. Could you please elaborate? Where do you get the parts? And how do you calibrate?

Thanks.

Any updates from the OP?

[osborni]

The stock fuel sender is a variable resistance type sender. 10 ohms at empty and 260 at full (IIRC for a m3).

A pull up resistor allows you to convert the resistance in the sensor into a voltage that can be put into the DAQ system.

At the bottom (i use R-T stuff, but the principle is the same):
http://www.race-technology.com/wiki/...ibrations#toc3

Calculator to figure out the resistance levels:
http://www.electronics2000.co.uk/cal...calculator.php

For calibration, I would leave the DAQ system at the default so you can see the raw voltages. Take a reading when the tank is empty, then add a gallon at a time and take a reading every time until the tank is full. You will then have all the information you should need to convert the raw input voltage to gallons or a % of tank fill.

I would use a 250 Ohm resistor in place of the 1k resistor, that should give you 2.55 volts at full and 0.19 volts at empty with a stable 5 volt supply voltage. Stable supply volts are critical as the resulting voltage will vary depending on the supply volts.

You will need to be careful that you do not exceed the amp limit of your voltage supply (I do not know if you dash unit has a reference voltage supply or what the current limit is). At 5 volts, you should see about a 0.020 amp load. If you do not have a reference voltage out, you will also need to get a "linear voltage regulator", a few capacitors and a project board at Radio-shack. About $7 all done.