new guy and keeping it simple

[mah2092]

Howdy....
I purchased my EFI tuner and programming from an outside vendor. No regrets. I am trying to learn a few things but one of my first goals is to get the gauges accurate. Figuring out the speedo was easy; i also changed the "check oil light" mileage to coincide with the extended oil drain intervals. The one that is eating me up right now is the fuel gauge. I did a search and I have seen that some people had the same initial problem. When the mt light would come on I could only fill it up with 18 gall. An 8 gall reserve? My lb7 was right around 2 gallons. I confirmed that the tank is factory and the 26 gall tank. The sending unit was replaced earlier with little improvement. I just recently attempted to adjust the readings by altering the gallons per voltage readings. I would scan the fuel primary voltage and determine how much it would take to fill up. No matter what, it wouldnt read less than 0.8 volts (once filled) and at 2.6 volts, I had a little over 5 gallons left. This was with the light on for an extended period. Now I have a half tank after driving 90 miles (I get about 20 mpg hiway) so I know what I did changed something but the wrong way. What I want to know is, if someone has a table for a fairly accurate fuel gauge without the large reserve, or an idea on how to custom my own. Thanks in advance. I am looking forward to getting more out of my truck.

[killerbee]

You can build your own voltage curve. You need to run the tank empty (keep a spare diesel can), and then head off to the gas station. Put in 2 gallons at a time, and write down the sender voltage off the PID. Build your own accurate curve from that data.

[mah2092]

Thanks for the reply...what i ended up doing was hooking up the scan tool, watching the voltage and then looking at the pump to see how much I had put in. Subtracted what I put in, then added that to the readings from the pump. I might not be explaining it correctly ( i had a LONG trip this weekend...and last weekend and I am at work) but, I think I ended up with some pretty good numbers. So far, it looks like I had 7 gallons left when at <1/4 tank. A LOT better than what it was (I had an 8 gallon reserve when the light came on). I am hoping that when the light comes on to check the voltage again and redo the numbers on the low end. I had to guess at them because I did not want to run truck dry. When I am satisfied with what I have, I will post it.