I am trying to get to the bottom of erratic fuel levels from the stock sender in my 2003 EP3 race car. According to my research these are the voltage values that are sent my the sender. AFAIK there is a 120ohm resistor involved therefore I calaculated the following values:
Fuel level calibration table
Voltage (V), Fuel Level (%)
1.43, 100
2.00, 75
2.50, 50
3.00, 25
3.57, 0
Can someone confirm if this table is right? I cant find any documentation on the colours. Does this look correct?
The colors represent how small or big the number in the table is.
It has nothing to do with the fuel level itself.
It is a general way to visualize the values in the table.
You are creating a table that shows the fuel level in percent.
So, 100% would be a full tank.
After a days testing, I am still seeing erratic/incorrect fuel readings. The car started the day indicating 85% tank. I ran 4x 20min sessions in the AM and 4x 20 min sessons in the afternoon (Brands Indy) and the ADU is now showing 77% - I know I used more fuel than 8% of a 50L tank.
Its a Honda EP3 and is using a standard tank float sender. The factory manual says this:
If you look at this example log (from one session), it says I used 2.42L, yet the ecu.fuellevel starts at 78 and ends at 77 and even goes up at the end!
By chance, has anyone else got Honda Civic Type R (EP3) that could share their analogue input ‘fuel level’ calibrated sensor settings?
As I said, I don’t trust the readings here, if I took the car to the petrol station, from experience, I would say the tank is probably 3/4 empty.
I really would appreciate some help here ensuring the setup is correct. I cant figure out what is happening (apart from the unlikely chance the intank fuel sender is faulty).
Hi firstly fuel used has nothing to do with fuel level sender is calculated at ecu secondary if you want any sensible reading there is no other way to calibrate sender like drain the fuel completely and fill tank is small amounts i normally use 10% fuel tank capacity for one step at the table. fuel level is practically never linear firstly float at the tank moving on arc so 10mm level at the bottom is not equal 10mm level when the float arm is horizontal. and second fuel tanks this days is not regular shape so capacity cant really be linearised..
OK - That makes total sense, however as I have the factory values for 4 ranges, surely it should be a case of replicating these into voltages so that the ADU interprets the fuel level sender values properly?
I am not an auto electrician! I have very basic knowledge and come here to (a) learn and (b) make sure things are right. Your input is appreciated but don’t assume everyone is an expert.
per the numbers you’ve given, this is what I math’d to be the correct calibration.
That said, my experience has also been that filling it from empty to full is the only way to be truly accurate. I usually use the FSM as a starting point and calibrate as not a single car i’ve done this for is ever perfect with the FSM numbers.
Greg’s point about non-linearity is spot on
