How much does correct MPH affect tune? Tuner quit on me
My car is currently being tuned and was hoping the experts on here could give me some insight. It is a Gen1 Coyote Crate motor with Ford Racing Control pack version A manual transmission. The car has been tuned NA for 7 years and has run flawlessly. I finally got around to adding a turbo I needed a new tune.
Issues my car was having with new tune.
-Stalling when coming to a stop
On Rev9 the tuner gave up and blamed my combo (which ran perfectly on previous tune with turbo installed and boost set at 0)
After he quit I figured out how to look at a DL myself and immediately noticed a MPH discrepancy. Logs showed my car at 0 mph until actually going 25mph and when at 7k rpm in 3rd showed 35mph in the log. Back in the early days of GEN 1 Coyote swaps stalling was a common issue. Ford Racing discovered it was the lack of a speed input so they would send you two pins to input speed to the ECM and the problem was solved. Knowing this but not wanting to ruffle feathers I asked the Tuner if the mph being off could be the cause of the stalling issue. The tuner quickly sent me a change so mph now matched. Lo and behold the car no longer stalled once mph was correct.
Now, I discovered this myself after Rev 9 and suspect all the changes that were made chasing issues were because of the MPH and are still in the current tune. I would expect that after the realization of the speed issue the tuner would have started over with a clean slate but I don't know exactly what would have been affected and if this would be necessary? I am wondering what changes may have been made, if they could be the cause of the current issue and what other areas would be affected.
The current issue is, after a cold start any throttle input around 1500-2000 rpm to normally accelerate results in lean popping and bucking. Timing goes below zero and STFT shows 35% fuel added with Lambda around 1.5. i.e. it's lean.
Thanks for any help.