Hey everyone as most of ya'll know I purchased a Scanguage II a couple weeks before I made my 2,000+ mile trip well I have been quite dissappointed with it's accuracy! When I purchased my scanguage and got it hooked up it consistently displayed in the 19Mpg area while I was driving at 75 Mph but after my second tank of fuel during my trip the fuel mileage has dropped and now it's showing that my truck is only averaging 9 MPG! I have figured up my fuel mileage after every fillup and according to my calculations i'm averaging 16.6 mpg now but I have added around 600-700 pounds in my bed and back seat and i'm also driving through mountains so that's causing my mileage to drop but what I don't understand is why has my scanguage lost so much accuracy? With my real time fuel mileage it hasn't gotten over 11mpg since then is something wrong with my scanguage? Thanks for the help!

 

Are you running a CAI? The Scangauge computes its mileage figures mostly from the MAF sensor. If your sensor is off a bit, or doesn't have a MAF screen in front of it to smooth the flow into the sensor, the sensor's signal will be off and therefore your gauge will be off.

Also, did you configure the scangauge cmopletely? You have to input the engine size, and calibrate it after your first tank.

After inputting the engine size and calibrating it after the first tank, my SG is accurate within 1 mpg on my '99.

 

Yes, make sure you have you MAF set up correctly. You need do undo the battery after installing one so it "learns" how to set up proper mixture levels. And make sure you setup like pinhead said. That will definately cause wrong numbers. and BTW pinhead, its accurate to within .1 MPG

 

Once I updated all of my engine info it was within .5 mpg of a manual readout. Probably just need to do that

 

Yea I have set everything up on the Scanguage. Tanks size,Engine Size and I have taken to battery cables off for a couple minutes and reattached them to see if it would help but no luck! I still have the factory intake so that shouldn't be a problem! Another thing I have noticed too is that the tachometer is reading about 50 rpms lower than what the factory tach is reading on my truck too! Thanks for the help!

 

i to am having problems. i took a road trip.....said i averaged 16MPG but then i filled up and on the way back it said 4MPG and when i filled up i told it how much gallons i added. also i would floor it and my MPG would go up the only way i fixed this was to reset everything back to default and then it read right? it also saved the gallons i had so i dunno im still playing with it