PV TT idle issue

[Sunny Jim]

I am perplexed with the following issue at idle.
Start the engine cold and it acts according until it settles to correct idle speed.
Shut the engine down and restart it.
At approximately 10 seconds from start it stumbles, spark timing momentarily increases and idle drops.
Within a couple of seconds the engine returns to correct idle.
When the engine is up to running temp, the issue is almost unnoticeable.
So I have chased IAC crank to run/ IAC warm up tables, warm up enrichment, spark tables, VEs and closed throttle spark and so on.
This anomaly that continually occurs at approximately 10 seconds has me baffled.
Any thoughts would be appreciated.

[hrdtail78]

When you stop the bike before restart.  Do you use kill switch or shut down bike with main and kill before restart?  If the bike dies during warm up or killed by switch only.  This will not activate warm up enrichment table.  Key needs to be cycles also from best of my understanding. 

Something I would pay attention to during this in the logs is where you are at in your VE table.  With throttle by wire.  The cells you can be in while bike is getting up to operating temp is not the cell it is in as a complete warmed up bike.  This is because of idle target and blade being used as IAC.  When looking at the cells you are in.  It's also a good idea to look at the surrounding cells for those.

I would also make sure there is no intake leak warmed up, not fully warmed up and cold.

[Sunny Jim]

When you stop the bike before restart.  Do you use kill switch or shut down bike with main and kill before restart?  If the bike dies during warm up or killed by switch only.  This will not activate warm up enrichment table.  Key needs to be cycles also from best of my understanding. 

Something I would pay attention to during this in the logs is where you are at in your VE table.  With throttle by wire.  The cells you can be in while bike is getting up to operating temp is not the cell it is in as a complete warmed up bike.  This is because of idle target and blade being used as IAC.  When looking at the cells you are in.  It's also a good idea to look at the surrounding cells for those.

I would also make sure there is no intake leak warmed up, not fully warmed up and cold.

So today we revisited the VEs. - no change!
We exchanged the inlet manifold for a SE 55mm. - no change!

The dip in idle is almost exactly 10 seconds every time the bike is started.
Idle AFR is 14.0:1
We will chase the IAC tables again tomorrow.
A question!
Could it possibly be the fact that it is a target tune issue?

[hrdtail78]

Looking at the process and the modes the ECM go through before it actually get to the VE tables.  It's about 10 seconds.     You can change one of your VE tables to all 20's.   Start bike and then measure time before it goes to one cylinder to see this. Makes me believe this problem isn't any start or start to run table. 

I'll claim ignorance with TT, but don't you have control by temp of when the ECM pays attention to this input.   You could leave it on and raise temp threshold to something you know the bike isn't going to reach for testing.     

With the timing jump you mentioned.  Under idle control.  There should be a table that allows timing to change to hit target idle and there is a table of how much timing can be modified from closed throttle table to control idle.  You can see if shutting this off addresses the idle jump or if another table is causing it.   

"At approximately 10 seconds from start it stumbles, spark timing momentarily increases and idle drops.
Within a couple of seconds the engine returns to correct idle." 

Map what the IAC steps are doing at this time.  If it is closing and then opens as engine warms up.  It can be a sign of intake leak that seals as engine is warmed up.    Engine speed will respond to ignition changes faster than air and/or fuel changes. 

 

[Sunny Jim]

Looking at the process and the modes the ECM go through before it actually get to the VE tables.  It's about 10 seconds.     You can change one of your VE tables to all 20's.   Start bike and then measure time before it goes to one cylinder to see this. Makes me believe this problem isn't any start or start to run table. 

I'll claim ignorance with TT, but don't you have control by temp of when the ECM pays attention to this input.   You could leave it on and raise temp threshold to something you know the bike isn't going to reach for testing.     

With the timing jump you mentioned.  Under idle control.  There should be a table that allows timing to change to hit target idle and there is a table of how much timing can be modified from closed throttle table to control idle.  You can see if shutting this off addresses the idle jump or if another table is causing it.   

"At approximately 10 seconds from start it stumbles, spark timing momentarily increases and idle drops.
Within a couple of seconds the engine returns to correct idle." 

Map what the IAC steps are doing at this time.  If it is closing and then opens as engine warms up.  It can be a sign of intake leak that seals as engine is warmed up.    Engine speed will respond to ignition changes faster than air and/or fuel changes. 

 

So there are unequivocally no I take leaks.
I have isolated the VEs to a set value on both cylinders( individually) to identify any changes in the collected data.
I have even gone back to basics and checked compression and spark plug condition . - all good.
I flattened the closed throttle spark gain and even switched off the warm up enrichment - no change.
I think the issue is in the the IAC factors - these appear to be the key drivers that are affected by
Engine temp.
Or maybe there is an underlying issue with my ecu/ PV. The latter I doubt , but I am missing something here and I have dug me a rabbit hole!!!

[Sunny Jim]

Looking at the process and the modes the ECM go through before it actually get to the VE tables.  It's about 10 seconds.     You can change one of your VE tables to all 20's.   Start bike and then measure time before it goes to one cylinder to see this. Makes me believe this problem isn't any start or start to run table. 

I'll claim ignorance with TT, but don't you have control by temp of when the ECM pays attention to this input.   You could leave it on and raise temp threshold to something you know the bike isn't going to reach for testing.     

With the timing jump you mentioned.  Under idle control.  There should be a table that allows timing to change to hit target idle and there is a table of how much timing can be modified from closed throttle table to control idle.  You can see if shutting this off addresses the idle jump or if another table is causing it.   

"At approximately 10 seconds from start it stumbles, spark timing momentarily increases and idle drops.
Within a couple of seconds the engine returns to correct idle." 

Map what the IAC steps are doing at this time.  If it is closing and then opens as engine warms up.  It can be a sign of intake leak that seals as engine is warmed up.    Engine speed will respond to ignition changes faster than air and/or fuel changes. 

 

So there are unequivocally no I take leaks.
I have isolated the VEs to a set value on both cylinders( individually) to identify any changes in the collected data.
I have even gone back to basics and checked compression and spark plug condition . - all good.
I flattened the closed throttle spark gain and even switched off the warm up enrichment - no change.
I think the issue is in the the IAC factors - these appear to be the key drivers that are affected by
Engine temp.
Or maybe there is an underlying issue with my ecu/ PV. The latter I doubt , but I am missing something here and I have dug me a rabbit hole!!!

This consistent stumble has me in a pickle.
It occurs a
Split second or so before the O2 sensors start signalling.

[Sunny Jim]

Looking at the process and the modes the ECM go through before it actually get to the VE tables.  It's about 10 seconds.     You can change one of your VE tables to all 20's.   Start bike and then measure time before it goes to one cylinder to see this. Makes me believe this problem isn't any start or start to run table. 

I'll claim ignorance with TT, but don't you have control by temp of when the ECM pays attention to this input.   You could leave it on and raise temp threshold to something you know the bike isn't going to reach for testing.     

With the timing jump you mentioned.  Under idle control.  There should be a table that allows timing to change to hit target idle and there is a table of how much timing can be modified from closed throttle table to control idle.  You can see if shutting this off addresses the idle jump or if another table is causing it.   

"At approximately 10 seconds from start it stumbles, spark timing momentarily increases and idle drops.
Within a couple of seconds the engine returns to correct idle." 

Map what the IAC steps are doing at this time.  If it is closing and then opens as engine warms up.  It can be a sign of intake leak that seals as engine is warmed up.    Engine speed will respond to ignition changes faster than air and/or fuel changes. 

 

So there are unequivocally no I take leaks.
I have isolated the VEs to a set value on both cylinders( individually) to identify any changes in the collected data.
I have even gone back to basics and checked compression and spark plug condition . - all good.
I flattened the closed throttle spark gain and even switched off the warm up enrichment - no change.
I think the issue is in the the IAC factors - these appear to be the key drivers that are affected by
Engine temp.
Or maybe there is an underlying issue with my ecu/ PV. The latter I doubt , but I am missing something here and I have dug me a rabbit hole!!!

This consistent stumble has me in a pickle.
It occurs a
Split second or so before the O2 sensors start signalling.

So its the target tune!
No target tune , no problem!
It's a long winded explanation!
But basically my DIY tune Ability vs target tune is in question!