Power. Vision. auto tune basic and VE tables. ???

[rich1]

When doing an auto tune basic session I get hits to cells outside of the narrow band closed loop range. This causes changes in the VE tables outside of the narrow band closed loop range. Does the ECM ignore those data points or do I need to manually go back in and change them back? Thanks.

[aswracing]

When doing an auto tune basic session I get hits to cells outside of the narrow band closed loop range. This causes changes in the VE tables outside of the narrow band closed loop range. Does the ECM ignore those data points or do I need to manually go back in and change them back? Thanks.

The ECM does not ignore them. It uses them to determine how much air is flowing through the motor.

Why would you want to change them back? You want your airflow model to be as accurate as possible. In fact, a person could argue that those cells are even more important to get right than the closed-loop areas, since the ECM has no feedback there.

[remington007]

In Auto Tune Basic the closed loop area is extended to populate more of the VE tables. Timing is also retarded -4 degrees on the entire map.

[aswracing]

Oh wait, maybe you're concerned that those hits aren't valid because the data is taken outside of closed loop?

When you enter narrow band autotune mode, the entire AFR table is rewritten to put you in closed loop in all cells (14.6).

When you export the learned values, your previous AFR table is restored into the result tune.

[rich1]

Yes. That's what I was asking. Those cells at say 5000 rpm are outside of the closed loop. But when I save and export the auto tune, the VE tables in those high RPM ranges are changed. Not restored to the previous values that were in the tables at higher rpm. Thanks

[rich1]

When doing an auto tune basic session I get hits to cells outside of the narrow band closed loop range. This causes changes in the VE tables outside of the narrow band closed loop range. Does the ECM ignore those data points or do I need to manually go back in and change them back? Thanks.

The ECM does not ignore them. It uses them to determine how much air is flowing through the motor.

Why would you want to change them back? You want your airflow model to be as accurate as possible. In fact, a person could argue that those cells are even more important to get right than the closed-loop areas, since the ECM has no feedback there.

I just don't understand how that part of it works. I wasn't sure what the result would be. So the bottom line is VE table changes outside of the closed loop range isn't a bad thing? If not I'm good. Thanks

[Coyote]

When doing an auto tune basic session I get hits to cells outside of the narrow band closed loop range. This causes changes in the VE tables outside of the narrow band closed loop range. Does the ECM ignore those data points or do I need to manually go back in and change them back? Thanks.

The ECM does not ignore them. It uses them to determine how much air is flowing through the motor.

Why would you want to change them back? You want your airflow model to be as accurate as possible. In fact, a person could argue that those cells are even more important to get right than the closed-loop areas, since the ECM has no feedback there.

I just don't understand how that part of it works. I wasn't sure what the result would be. So the bottom line is VE table changes outside of the closed loop range isn't a bad thing? If not I'm good. Thanks

Not perfect but it's better than no tuning at all there.

[aswracing]

I just don't understand how that part of it works. I wasn't sure what the result would be. So the bottom line is VE table changes outside of the closed loop range isn't a bad thing? If not I'm good. Thanks

Well, it's important to get as much of the VE tables correct as possible, regardless of whether any given cell will be used in closed-loop or open-loop. That's because the VE table values are a critical part of the airflow calculation performed by the ECM, regardless of whether it's operating in open or closed loop. In fact, if anything the VE table values are more important in open-loop areas of the map, since there's no sensor feedback to incorporate.

Therefore, autotune tries to log data everywhere, regardless of whether the cell will ultimately be used open or closed loop.

Since Autotune basic mode is using the stock narrow-band sensors, it has to force the entire AFR table to be closed-loop (14.6) so that it can use the sensors everywhere and thus populate any cell you can hit. 14.6 is pretty lean for the high load, high rpm areas, so Autotune basic also backs out 4 degrees of spark advance across the board to keep you from melting down your motor. Both of these changes are temporary, though, incorporated only into the map used for logging, and they are not part of the result tune that you export once you're done logging, your original AFR and spark advance tables get restored.

Autotune pro mode doesn't require closed-loop mode during logging, since it's using wide band sensors that respond to a wide range of AFR's. So the AFR table gets forced to 13:1 instead, which is a whole bunch better and safer than 14.6. Again, this gets backed out in the exported result tune, and your original AFR table is restored. Autotune pro mode does not mess with the spark advance.

Bottom line, you want accurate values in all cells of the VE tables regardless of whether or not the cell will ultimately be used open loop or closed loop, which is why autotune is designed to log and modify in those cells.

[rich1]

Wow. Thanks. That explains everything I wanted to know

[Herko]

...you want accurate values in all cells of the VE tables regardless of whether or not the cell will ultimately be used open loop or closed loop...

Exactly. Well said.
This is often overlooked or ignored.
Some might be surprised the how the adjacent cell factor can influence a target cell.
An experimentation of adjacent cell value manipulation with good data logging can be an eye opener.