Have used my Scan Gauge II in various vehicles with no problems. BUT, can not get a reliable reading on instant or average fuel mileage in my 2009 6.4 Turbo diesel 3500 4x4. Any one having any luck with this set up? Have tried both Diesel A and Diesel B settings, no luck. To get anything even close to right I have to have the SGII set at +50% when pulling my camper, +80% when pulling my boat, and +144% when running empty. Even then it only comes sorta close. Have set the SGII by actual gallons used. Overhead counsel is pretty accurate for overall mileage. Don't want to reset it every time I fuel up however. Any help from someone actually getting it to work would be greatly appreciated. Sam

 

Did you change your engine size to 6.4 or 6.7? Did you change your tank size to match your 3500? Then the Fillup Screen will calibrate better when you input gallons of fuel.
Good Luck