Recently got my original Dyno tune emailed to me. The one in my Ecal II went corrupt and messed things up. With the new tune installed I played around with timing, A/F, and shift points. Had great power and acceleration. I am at +2 on global timing and A/F. Then noticed by GPS that my speed was off by 4 MPH. speedo read 80 and the actual by GPS was 76. I adjusted the tire size from 645 rev per mile to 660 and got it dead on. The problem I am having is that with that corrected if feels like the bottum fell out of it and the sound of the exhaust changed from rappy and crisp to a blaw drone tone. Anyone have any Ideas? I could sure use some help.

 

Is the Xcal2 capable of reading vehicle speed? If so, adjust it till the GPS agrees with the device, NOT the speedometer. Ford speedometers read a bit high by design.

Your tune may again be corrupt.

 

Talked with tarajerame and he thinks it maybe because the xcal was hot and it was hot outside as well. I brought the tuner in the house and let it cool down over night. This morning I reprogramed the truck and let it warm up at idle to do initial adjustments and let the IAC adjust. I will take it for a spin in a bit to see if that was the problem.