ECU Map and PVC with AT

[Claviger]

A point I didn't want lost in the above post:

Throttle response is directly related to how close to right the fueling table values are. If they're way off and the AT needs to add a large amount of fuel to fix a map that's way off, it causes it to run much worse than having a very close map with small AT adjustments.

This is first hand experience. With Nels and Bobs tunes in my bike, the mapped values in the table are already bang on, and it rides very smooth and instantly responds to inputs. With a way off map which is relying on the AT target tables to hit the right AFR, the bike will make similar max power and torque, but feels "lazy" for lack of a better word.

 

[Claviger]

Final post on the topic I swear:

The reason the AT is continually leaning it out is that the Rocket ECU has acceleration enrichment build into it, but it is a hidden value. When you open the throttle fast, it dumps an extra shot of fuel, NOT calculated in the standard tables, its a value based on gear/rpm/speed of throttle opening. This extra shot of fuel, causes it to swing richer than the AT wants it to be, BUT, you need that extra shot of fuel, all fuel injected vehicles do this to varying degrees. That slight rich swing during the transition period, cause the AT algorithm to decide it needs to cut out more fuel. So you accept, and go riding. Then you get another accel event, and the AT says nope, need to pull more fuel again, etc etc etc and its a dirty cycle leading to a very lean motor.

THIS is exactly why I pulled the 550cc injectors off my bike, without a way to adjust the accel enrichment, they were impossible to tune right because the ECU would calculate an opening time designed for the stock injectors, but when the 550s were opened that long it swung REALLY rich (like 9:1) for a second and bogged, then took off like a bat out of hell when accel enrichment was over.

 

[Paul Bryant]

Interesting stuff Rob, Andrew (Sleeves) does all my tuning so no doubt he will be digesting all of this then dumping a new, or modified map in my bike. . . . as he does !
The more I think about this (from what you have said) the more I feel that this is where my problem is.
As I say when I give it a handful, it takes off just fine.

 

[sleeves]

Final post on the topic I swear:

The reason the AT is continually leaning it out is that the Rocket ECU has acceleration enrichment build into it, but it is a hidden value. When you open the throttle fast, it dumps an extra shot of fuel, NOT calculated in the standard tables, its a value based on gear/rpm/speed of throttle opening. This extra shot of fuel, causes it to swing richer than the AT wants it to be, BUT, you need that extra shot of fuel, all fuel injected vehicles do this to varying degrees. That slight rich swing during the transition period, cause the AT algorithm to decide it needs to cut out more fuel. So you accept, and go riding. Then you get another accel event, and the AT says nope, need to pull more fuel again, etc etc etc and its a dirty cycle leading to a very lean motor.

THIS is exactly why I pulled the 550cc injectors off my bike, without a way to adjust the accel enrichment, they were impossible to tune right because the ECU would calculate an opening time designed for the stock injectors, but when the 550s were opened that long it swung REALLY rich (like 9:1) for a second and bogged, then took off like a bat out of hell when accel enrichment was over.

Hi Claviger

Think this last post has fully explained the "why I've leaned out" thanks. All other posts you've done are incredibly helpful too got some work to do when I get back. I had wondered why it didn't bog down like my old V8's when the pumper on the carbs clapped out.

Will do some more study and experiment when back home.

Thanks again

 

[sleeves]

Final post on the topic I swear:

The reason the AT is continually leaning it out is that the Rocket ECU has acceleration enrichment build into it, but it is a hidden value. When you open the throttle fast, it dumps an extra shot of fuel, NOT calculated in the standard tables, its a value based on gear/rpm/speed of throttle opening. This extra shot of fuel, causes it to swing richer than the AT wants it to be, BUT, you need that extra shot of fuel, all fuel injected vehicles do this to varying degrees. That slight rich swing during the transition period, cause the AT algorithm to decide it needs to cut out more fuel. So you accept, and go riding. Then you get another accel event, and the AT says nope, need to pull more fuel again, etc etc etc and its a dirty cycle leading to a very lean motor.

THIS is exactly why I pulled the 550cc injectors off my bike, without a way to adjust the accel enrichment, they were impossible to tune right because the ECU would calculate an opening time designed for the stock injectors, but when the 550s were opened that long it swung REALLY rich (like 9:1) for a second and bogged, then took off like a bat out of hell when accel enrichment was over.

Hi Claviger

Think this last post has fully explained the "why I've leaned out" thanks. All other posts you've done are incredibly helpful too got some work to do when I get back. I had wondered why it didn't bog down like my old V8's when the pumper on the carbs clapped out.

Will do some more study and experiment when back home.

Thanks again

Interesting stuff Rob, Andrew (Sleeves) does all my tuning so no doubt he will be digesting all of this then dumping a new, or modified map in my bike. . . . as he does !
The more I think about this (from what you have said) the more I feel that this is where my problem is.
As I say when I give it a handful, it takes off just fine.

 

[sleeves]

Final post on the topic I swear:

The reason the AT is continually leaning it out is that the Rocket ECU has acceleration enrichment build into it, but it is a hidden value. When you open the throttle fast, it dumps an extra shot of fuel, NOT calculated in the standard tables, its a value based on gear/rpm/speed of throttle opening. This extra shot of fuel, causes it to swing richer than the AT wants it to be, BUT, you need that extra shot of fuel, all fuel injected vehicles do this to varying degrees. That slight rich swing during the transition period, cause the AT algorithm to decide it needs to cut out more fuel. So you accept, and go riding. Then you get another accel event, and the AT says nope, need to pull more fuel again, etc etc etc and its a dirty cycle leading to a very lean motor.

THIS is exactly why I pulled the 550cc injectors off my bike, without a way to adjust the accel enrichment, they were impossible to tune right because the ECU would calculate an opening time designed for the stock injectors, but when the 550s were opened that long it swung REALLY rich (like 9:1) for a second and bogged, then took off like a bat out of hell when accel enrichment was over.

Hi Claviger

Think this last post has fully explained the "why I've leaned out" thanks. All other posts you've done are incredibly helpful too got some work to do when I get back. I had wondered why it didn't bog down like my old V8's when the pumper on the carbs clapped out.

Will do some more study and experiment when back home.

Thanks again

 

[sleeves]

Whoops marginal internet down the bottom of South Island

 

[sleeves]

Interesting stuff Rob, Andrew (Sleeves) does all my tuning so no doubt he will be digesting all of this then dumping a new, or modified map in my bike. . . . as he does !
The more I think about this (from what you have said) the more I feel that this is where my problem is.
As I say when I give it a handful, it takes off just fine.

Paul

We need to reset your PVC Map as Rob says, you have same problem I've got from trimming the PCV AT.

 

[sleeves]

Oh rereading your posts I noticed I had set very similar F/L switch points on my map to ones you suggest in first post but once the issues started I reverted them to a previous MAP setting.

Am on holiday and a long way from home, didn't have time to experiment.

 

[Paul Bryant]

Paul

We need to reset your PVC Map as Rob says, you have same problem I've got from trimming the PCV AT.

Cool, I won't change the plugs .... just yet.