Assuming I were at the dyno, and I replaced the current tune "A" with the new tune "B", would I have to drive the car to allow the PCM cells to populate or calibrate before making a pull or can I just immediately make the pull?

It seems to me that after a tune is installed then things need to "run in" before the PCM can properly operate. Am I correct here?

Thanks

 

You saying you have two different PCMs? Or if you are tuning on the Dyno?

Either way, with my experience of getting dyno tuned. They flash the new tune on, crank it up, and make a pull. I haven't heard of needing to drive it so that the computer can 'learn' anything else or calibrate itself to be able to fully utilize the tune.

After the tune however, the tuner took me for a drive to make sure everything felt good before he left. He didn't mention anything special about it needing to calibrate, simply wanted to make sure I was happy with the gains/performance of the new tune.

 

You can make the pull immediately after installing the new tune. There is no need for the computer to "relearn" itself.

 

Someone correct me if I'm wrong, but I don't think there are any "cells" to populate at WOT. I could see that being the case for part throttle performance, but on the dyno you're making a wide open throttle pass and going off of a fuel map that's reliant on the tune, not your O2 readings.

 

White, you are correct. At WOT you are essentially in a closed loop and everything is predetermined by the tune.

 

When I had my dyno tune done my A/F was 12.8 a couple weeks later I borrow a wideband to do some fine tuning and it was 10.8. The fuel trims were adding in cruising and idle so when I hit WOT it was going very rich. Thats the learning you're worried about. I then corrected the tune to have the trims around 125 during cruising so that my WOT A/F would stay consistent.

 

Well your last BLM cell you were in DOES come into effect at WOT. IF you were running lean and the PCM was adding some fuel, then in WOT, it will continue to add that additional fuel on top of what additional fuel is programmed in for WOT.

If your last BLM cell was rich, <128, and it was cutting fuel, then it will continue to cut that amout from the amount programmed for WOT/PE.

So, yes, if you just reflashed, all the BLMs will be at 128, which means add / cut NO fuel. If your tuner only adjusts your WOT/PE fueling and makes a pull and claims it to be good...then after driving, your PE fueling can and most likely will be off than what it was tuned to on the dyno.

Maybe Injuneer will chime in here on this as this is what was explained to me sometime ago on the PCM forum, and have since observed this with my wbo2.

Bill, that might explain why you have more knock if you ran that WOT blast right after reflashing...so make sure you drive it up thru the highest BLM cells a few times before going WOT. Maybe your previous tune had them adding even more fuel and after reflash it was not yet up than high in the last BLM cell...just a possibility. What are your BLMs in most of the cells while driving??