E38 fuel level sensor calibration

I posted this on the EFIlive forum... with no big help so far.. maybe over here is one who did that before.. ;-)

One thing I didn't care about in my swap (2007 5.3 LMG in 1997 2dr 4wd Tahoe)
is the fuel level sensor. I had to built a new connecting rod for the level sensor, 'cause the '97 Tahoe's gas tank is a lot deeper than the 2007 composite tanks.
I also had to modify the fuel pump module to fit that deep tank.


http://i301.photobucket.com/albums/n...m/IMG_3524.jpg

http://i301.photobucket.com/albums/n...m/IMG_3527.jpg

http://i301.photobucket.com/albums/n...m/IMG_3531.jpg

http://i301.photobucket.com/albums/n...m/IMG_3533.jpg

The manual states 40ohms resistance for a full tank and 250 ohm resistance for the empty tank. The E38 sees 5V for the empty tank and 0V for the full tank. In my 1997 Tahoe gas tank I could manage to have 250ohms empty and 50ohms full.... not exact but close to the spec.

Then I looked up the calibration in EFIlive : There is F0504 which is the tank capacity in liter and F0505 as sensor calibration.
I have F0504 113l. When I read those values with the scan tool:

http://i301.photobucket.com/albums/n...sensor_pid.jpg

I recieve 0.8V for a full tank. Seems ok so far but what seems strange to me is I read 99l as Fuel tank rated capacity GM.FTRC although I programmed F0504 113l in the tune tool.

http://i301.photobucket.com/albums/n.../tank_size.jpg

any ideas? Did I miss something?

Maybe I'm wrong, isn't GM.FTRC exactly what I set with F0504 in the tune??? If yes then there is something wrong cause a F0504 of 113litres returns a GM.FTRC of 99litres regardless what I do with F0505.

I would expect if I set F0504 to 113litres that I can see this in GM.FTRC as 113 litres and that the calibration of F0505 then should be set to 113litres at 0V fuel level sensor voltage or in may special case 0.8V is equal to 113 litres as I only have 50ohms with a full tank and not the desired 40 ohms..

from the tuning side:
I am using the following VIN of a 2007 Tahoe as data source.
The ECM, TCM, BCM, Cluster and TCCM are updated via TIS to the latest tunes based on that VIN

1GNFK13037R238413

As far as I know a Tahoe only uses one fuel level sensor but I am not 100% sure..


a still confused Harald

my truck always tells me i have 200-250 gallons, so i'm not sure, i just assumed the computers didn't actually know how many gallons each vehicle held.