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... but by different amounts as compared to the GPS speed reading.
Hope these pics aren't too dark. They were taken with cruise control on, and on a level road I-5 in California. Truck stock tire size is 255/70R17, but it's rolling on 265/70R17's instead so it should be just a hair off. However, it is significantly off. The weird thing is that the speedo and what Torque Pro is showing the ECM reading as are about 5 mph off from each other!
Speedometer is reading @ 77-78 mph
Speedometer
GPS is reading 75.7 (which should be about correct considering the tire size difference from stock), but the ECM is reading 82 MPH!!! GPS and ECM speed reading in Torque Pro
I don't see the problem. The ECM reading doesn't mean anything. It isn't displayed anywhere except the Torque Pro.
The GPS is showing that the speedo is reading 1.7% high. The federal requirement for speedometers is that the speedometer be within 2%. Your speedo is within 2%.
I don't see the problem. The ECM reading doesn't mean anything. It isn't displayed anywhere except the Torque Pro.
The GPS is showing that the speedo is reading 1.7% high. The federal requirement for speedometers is that the speedometer be within 2%. Your speedo is within 2%.
Hmmm... I just assumed that the speedo was getting its reading from the ECM. Well, guess it's okay then.
So, my next question would be how would I recalibrate the speedo if I were to goto 33's/295's?
The speedo IS getting it's reading from the ECM. But the speedo is right, isn't it? There is a correction factor from the speed that you've accessed to the speedo. You can change the tire size in the ECM and that will change the speedo.
My point is that the 82 MPH is an internal calculation that if you didn't have Torque Pro you wouldn't know about it. The speedo is only 1.7% away from the GPS. Those are the only two speeds that matter.
