Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Occam]

I had some decel pop after exhaust install, only over 2k rpms.
Went into TTS and hit the enleanment table, now I get a pretty yellow flame crackling out the end of the exhaust after revving while parked.

I presume this means I should be leaning rather that fattening the table?

[cahdbiker]

Occam, I have read on numerous threads that popping on deceleration can be caused by an exhaust leak at the cylinder head. Hope it is something easy.CAHDBIKER

[Occam]

Welp, made a better audio only file but now trying to host it for a link here.
Still not the very best quality, as the only mic I wanted to subject to those sound pressure levels was an inexpensive dynamic Audio Technica...
The large diaphragm condenser stays in its case.

To the topic.
It only pops when I engine brake hard above 2k rpm. The exhaust gaskets were brand new when I installed the pipe. I'll check the fasteners a 3rd time for looseness.
It got worse after I started screwing with the enleanment tables; I think it's fine so long as I go the other way with the values or - here's a novel idea - leave it alone.
At 107 decibels, it's not a quiet exhaust and the baffle is called "Track Tuned" for a reason, I suppose.

 

[Doc 1]

The Decel table is the exact opsite of the Accel table.....the Accel table and Decel tables ONLY work as the throttle is being moved. The Accel adds or takes away fuel as you throttle up and the Decel table adds or takes away fuel as you throttle down.....they DO NOT work if the throttle isn't moving.
The Accel table adds fuel if you make the numbers larger and since the Decel is the opsite you add fuel by making the numbers smaller.
If you have decel popping after the throttle is shut down add fuel to the rpm range the popping is happening at in the 15 or 20 kPa columns on the fuel table.
Doc 

[rheiner]

The Decel table is the exact opsite of the Accel table.....the Accel table and Decel tables ONLY work as the throttle is being moved. The Accel adds or takes away fuel as you throttle up and the Decel table adds or takes away fuel as you throttle down.....they DO NOT work if the throttle isn't moving.
The Accel table adds fuel if you make the numbers larger and since the Decel is the opsite you add fuel by making the numbers smaller.
If you have decel popping after the throttle is shut down add fuel to the rpm range the popping is happening at in the 15 or 20 kPa columns on the fuel table.
Doc 

Thank you for this explanation. I've wonderered how this works. So actual numbers wise in the tables, what are you talking about when you say to add fuel or take away fuel? I know it must be trial and error but can you give us some numbers to start with?

Also, on one of my bikes, at 1,500 rpm (in 1st gear) if I open up the throttle off the line, my motor hits a dead spot and boggs down bad, almost coughing. It only does this at 1500 rpm, if I was at 1,800 or higher and did the same throttle movement, no problems at all. I'm wondering if it could be a defective electronic throttle body or maybe I need to add some accel fuel? 

[Doc 1]

The Accent is nothing more but a electronic controlled accelerator pump. If you wanted to add fuel to the accelerator pump you would increase the numbers in the column. I usually start adding at 48C down to the bottom of the column and I add 5 or 10% at a time.....load that in the bike and see how it reacts to your bike.
Decel table works backwards....add fuel to cool the pipe down so there isn't popping between shifts or popping as the throttle is being shut down, to add fuel you decrease the numbers and again I use the 5 to 10% at a time. If you get popping 1 or 2 seconds after the throttle is shut down the Decel table will help in that situation also, however if your costing to a stop and the throttle has been closed for more than 2 seconds you have to richen the AFR values in the columns to the left of 30 kPa (the 15 or 20 kPa columns) in the Lambda or AFR table.
Doc

[Occam]

Thanks for the info Doc, you're awesome.
I understand what you're saying, and I must have misread the TTS manual.
I thought what I was doing with the Decel column (smaller numbers) was enrichening for two seconds after the throttle closed.

I'll follow what you said as it is outlined as one of the fixes for this and seems like the most sound solution to what's happening.
I must admit, it is a good attention getter on the highway though, just to be sure the cages adjacent to me know I'm there.
 

[rheiner]

The Accent is nothing more but a electronic controlled accelerator pump. If you wanted to add fuel to the accelerator pump you would increase the numbers in the column. I usually start adding at 48C down to the bottom of the column and I add 5 or 10% at a time.....load that in the bike and see how it reacts to your bike.
Decel table works backwards....add fuel to cool the pipe down so there isn't popping between shifts or popping as the throttle is being shut down, to add fuel you decrease the numbers and again I use the 5 to 10% at a time. If you get popping 1 or 2 seconds after the throttle is shut down the Decel table will help in that situation also, however if your costing to a stop and the throttle has been closed for more than 2 seconds you have to richen the AFR values in the columns to the left of 30 kPa (the 15 or 20 kPa columns) in the Lambda or AFR table.
Doc

Good info. Thanks again.

[Occam]

Yes, I agree with rheiner!
Upon re-reading my last posts I did not covey my gratitude sufficiently.
Thank You Doc for pointing out which way to play this.
I'm augmenting my AFR table now, Saturday's runs will prove it out.

Thanks again!
 

3/26
Dropped the 20 kPa column down 5% and no snapping at all, but barely warm on kickstand. Nice long ride today will yield definitive results.

[dlaws01]

I'm voting for Doc for President!  Some day I will make it down your way for some engine work.

[strokerjlk]

Dropped the 20 kPa column down 5% and no snapping at all, but barely warm on kickstand. Nice long ride today will yield definitive results.

wondering how it worked out.......you went the wrong way in the 20 kpa area.
to add fuel there you raise the ve numbers.
or decrease Lambda/ AFR number

[Doc 1]

wondering how it worked out.......you went the wrong way in the 20 kpa area.
to add fuel there you raise the ve numbers.
or decrease Lambda/ AFR number

Actually you correct decel popping with the fuel table .....not the VE tables.  If you do use the VE tables to correct popping it has an effect on the math of the map and that effects the Adaptive Fuel tables ability to average their findings to make correct changes in the closed loop area. However there are some high performance builds or bad pipes, cam combos that stopping the decel popping requires fudging the values in the VE tables.....but.....by all means start with the kPa columns to the left of 30kpa in the fuel/Lambda table....so he did do it correctly.
Doc     

[Occam]

I continued down the same road - no pun intended - because a nice warmed-up ride still produced some decreased popping.
I started over and dropped the same column by 10%, which added a bunch of torque off idle thus adding rideability and all but eliminated the pop.
I can only get it snapping now if I am over ~4k and drop the throttle, and even then it's decreased. In other words, I have to work for it.
That's fine by me.

[strokerjlk]

Actually you correct decel popping with the fuel table .....not the VE tables.  If you do use the VE tables to correct popping it has an effect on the math of the map and that effects the Adaptive Fuel tables ability to average their findings to make correct changes in the closed loop area. However there are some high performance builds or bad pipes, cam combos that stopping the decel popping requires fudging the values in the VE tables.....but.....by all means start with the kPa columns to the left of 30kpa in the fuel/Lambda table....so he did do it correctly.
Doc     

thats why I said
or decrease Lambda/ AFR number
both work. and it takes both sometimes.

I can only get it snapping now if I am over ~4k and drop the throttle, and even then it's decreased.

just work the RPM area you hear it in now. it might take the rpm area above and below as well so if it is at 4000 rpm work 3500,4000 and 4500 a little.

[Occam]

Going for 2 or 3 Vtune runs in the next day or so, then after the 575s are plugged in Vtune again until I save pennies for dyno work.
Hope to duplicate Herko's results or get close.