Ok this is what i have i installed my program(1815 superchip) and i have 285/70-17's from the ground up i have 32 and a 1/8 inches @45psi so i set my tire size at 32 this is what i get at 60mph

speedo = 60mph

scan gauge II = 58

handheld GPS = 58

what is right the scangauge is reading from the PCM and the speedo gets its signal from the PCM so.......???

Thanks john

 

bump

 

i have no clue


The scanguage is right, thats all i know

 

I have the super chips also on my truck and It is about a mile or 2 off compared my handled gps.

 

Thanks for the reply this is what i have learned

I just got back from trying 32.50,33 and 31.75 the GPS and the scangage are always the same dead on each other the speedo is always 2mph faster this leeds me to the speedo is 2mph off from the factory would you agree.

John

 

The speedos are off 2-4 mph from the factory. This is because of the spring and such that is used for the speedo needle. I went through this same thing with my Edge, and alot of others have also. I just played with the numbers until I had my GPS and speedo reading the same and actually got it to within .2 mph, but then the Edge readout from the PCM was off (same reading as your scan gauge).

 

Hey PSH79 I see that you have a Airaid jr have you had any problems with it by that i mean the jr with the edge running lean I was told that sometimes with a tuner the motor can run lean I just bought one (airaid jr)and i have the 1815 tuner

John

 

Hi John, check your PM's I replied there.

Paul

 

Thanks PHs79

 

Not a problem, any time