Hi friends,
I have ace 2755, may anybody tell me where can I buy a 0/100 ohm fuel sender?
I think 2755 is very nice for the price (165 euro delivered in italy), it haves also some warning lamps,

foto
Rescued attachment ace2755.jpg

Hi,
Check out this thread:
http://www.locostbuilders.co.uk/viewthread.php?tid=46296

Not every sender can be corrected using a resistor.

Firstly you need to ensure that the sender works in the correct sense. For example, 0-100 ohms empty to full or 0-100 ohms full to empty. You then need to find a sender which is as close to 0-100ohms as possible but should not to be less than this. The sender I am using goes from 0-180 ohms and I can correct this back to 0-100 ohms by using a 220 ohm resistor in parallel.

Here is the formula to calculate the parallel resistance required:

R = (Rrequired * Rsender)/(Rsender - Rrequired)

eg (100 * 180)/(180-100) = 225 ohms (220 ohms is a standard value)

HTH,
Craig.

Thank you friends.....
..but there is a little problem:
if you put in parallel a resistor when tank is empty you have the right mesurament but when tank is for example 1/3 you do not have the right mesurament becouse a 0/100 sender should be 66.66 ohm, a 0/180 sender with 220 ohm resistor in parallel is about 40.74 ohm.
Have I miss anything?
......However I will use a (easy to find)0/180 ohm as you did.

Hi Rudy,
You are quite correct, there will be a non-linearity introduced by the parallel resistance which is why you need to choose a sender which is as close as possible the the resistance expected by the gauge.

Here are some calculations to show the distortion:
0% (0 ohm) = 0 ohm (error 0%)
10% (18 ohm) = 17 ohm (error 66%)
20% (36 ohm) = 31 ohm (error 55%)
30% (54 ohm) = 43 ohm (error 45%)
40% (72 ohm) = 54 ohm (error 36%)
50% (90 ohm) = 64 ohm (error 28%)
60% (108 ohm) = 72 ohm (error 21%)
70% (126 ohm) = 80 ohm (error 14%)
80% (144 ohm) = 87 ohm (error 9%)
90% (162 ohm) = 93 ohm (error 4%)
100% (180 ohm) = 99 ohm (error -1%)

As you can see the error decreases as the sender resistance increases which IIRC means it will get more accurate as the tank approaches empty. I don't think this will cause too many problems, especially if you are aware of it.

HTH,
Craig.

yes, Craig, you say the right.
Thankyou.