What should AFR be on decell to avoid popping?

[whetsel.m]

I have a wide band O2 sensor in front pipe. I had the bike dyno'd and the tuner said he couldn't get rid of the decell popping. O2 reads around 20 on decell. Is this too low? 08 FL 124" fatcat with cocentric baffle, woods 408-6

[CW#]

What ECM?

Pop can be treated with a combination of timing and AFR...

Of course there is always the possibility that a cam, engine, and pipes combo will never be tuneable for the street. I'm not familiar enough with your specs to say...

I got rid of mine by going one point (.1) lower on the AFR at each end of the RPM range of 1536 to 2304 and pulling the curve down a bit at a time until I was happy. Gas mileage suffered but it also keeps my engine cooler around town. I didn't change my timing but if I had been using a dyno service I'm willing to be I would have been happier with the gas mileage because they would have tweaked the timing.

My pipes were not meant for the street and that was my problem. No low end back pressure to speak of I think.

C#

[strokerjlk]

I have a wide band O2 sensor in front pipe. I had the bike dyno'd and the tuner said he couldn't get rid of the decell popping. O2 reads around 20 on decell. Is this too low? 08 FL 124" fatcat with cocentric baffle, woods 408-6

in your 20 kpa area of the AFR table take the afr to 13.0 from 1500 rpm to the bottom of the table 6200-or whatever max rpm is in your cal.
so the first row in the afr table take to 13.0 .if your idle is 35 kpa and better you can just do the whole row. if your idle hits 29 kpa at times . then only do 1500 rpm and higher.(idle of 29 kpa is polling off of the 20 kpa area up to 1500 rpms ) you can make slight decel tabel adjustments also ,adding fuel. to much fuel will make it feel like a on off switch ,so take a little at a time.
if that dosent work then you have to dial in the ve's better in decel. and work the timing . this gets build dependant . so just try adding fuel in the 20 kpa area. it might also take some tweaking of the 30 kpa area as well . but you have to make sure where decel is ,and not where your under light throttle. (or fuel mileage will suffer)

[HDMG]

Stroker, your reply about decreasing the AFR to 13 to eliminate decel pop confuses me.
I thought that the decel enleanment feature was to eliminate this problem.
You are suggesting going the other way.

can you explain further?

[WideWildGlide]

i think what means is going from let say 13.5 to 13 that mean a richer mixture HDMG

[strokerjlk]

i think what means is going from let say 13.5 to 13 that mean a richer mixture HDMG

Yes that's what I meant . Lower number , more fuel.
HDMG
The decel table isn't enough at times . Go to far and you have a on/ off feeling if you try to take it all out with just the decel table .
It's a balance of the tables .

[hrdtail78]

Can you see what your injectors are doing?

[HD/Wrench]

Another thought is to look at the area it is in decell KPA take the timing up to 42  and take the decell fuel and turn it off.  Some time the adding fuel method does not always work. I just did a V&H system that was being a bugger and had to add timing remove all decell fuel and it was super smooth not a burble at all .  Nothing wrong with either way some tunes may work with adding fuel other may work by removing. I find that removing works well and you will never get the shot ugh blast if the guy comes down a long down grade.   AZ had tons of long down grades ha ha love the mountains ..   Don't get fussy with it at first  make a large change one way or the other to see what it wants then work dial it in.  Good luck 

[1931jamesw]

Another thought is to look at the are it is in decell KPA take the timing up to 42  and take the decell fuel and turn it off.  Some time the adding fuel method does not always work. I just did a V&H system that was being a bugger and had to add timing remove all decell fuel and it was super smooth not a burble at all .  Nothing wrong with either way some tunes may work with adding fuel other may work by removing. I find that removing works well and you will never get the shot ugh blast if the guy comes down a long down grade.   AZ had tons of long down grades ha ha love the mountains ..   Don't get fussy with it at first  make a large change one way or the other to see what it wants then work dial it in.  Good luck 

[Ohio HD]

Another thought is to look at the area it is in decell KPA take the timing up to 42  and take the decell fuel and turn it off.  Some time the adding fuel method does not always work. I just did a V&H system that was being a bugger and had to add timing remove all decell fuel and it was super smooth not a burble at all .  Nothing wrong with either way some tunes may work with adding fuel other may work by removing. I find that removing works well and you will never get the shot ugh blast if the guy comes down a long down grade.   AZ had tons of long down grades ha ha love the mountains ..   Don't get fussy with it at first  make a large change one way or the other to see what it wants then work dial it in.  Good luck 

I wondered about adding timing to help loose popping Steve. Would you recommend adding timing in the 15 kPa only, or in the 15 and 20 kPa areas? This is an AFR MAP.

[strokerjlk]

Another thought is to look at the area it is in decell KPA take the timing up to 42  and take the decell fuel and turn it off.  Some time the adding fuel method does not always work. I just did a V&H system that was being a bugger and had to add timing remove all decell fuel and it was super smooth not a burble at all .  Nothing wrong with either way some tunes may work with adding fuel other may work by removing. I find that removing works well and you will never get the shot ugh blast if the guy comes down a long down grade.   AZ had tons of long down grades ha ha love the mountains ..   Don't get fussy with it at first  make a large change one way or the other to see what it wants then work dial it in.  Good luck 

I wondered about adding timing to help loose popping Steve. Would you recommend adding timing in the 15 kPa only, or in the 15 and 20 kPa areas? This is an AFR MAP.

do it in the closed throttle table 

[Ohio HD]

Another thought is to look at the area it is in decell KPA take the timing up to 42  and take the decell fuel and turn it off.  Some time the adding fuel method does not always work. I just did a V&H system that was being a bugger and had to add timing remove all decell fuel and it was super smooth not a burble at all .  Nothing wrong with either way some tunes may work with adding fuel other may work by removing. I find that removing works well and you will never get the shot ugh blast if the guy comes down a long down grade.   AZ had tons of long down grades ha ha love the mountains ..   Don't get fussy with it at first  make a large change one way or the other to see what it wants then work dial it in.  Good luck 

I wondered about adding timing to help loose popping Steve. Would you recommend adding timing in the 15 kPa only, or in the 15 and 20 kPa areas? This is an AFR MAP.

do it in the closed throttle table 

Gotcha, makes sense.   

[1931jamesw]

If you have a big difference in the closed throttle table from the main spark table it can get funky on idle during warmup.

[strokerjlk]

If you have a big difference in the closed throttle table from the main spark table it can get funky on idle during warmup.

who said anything about idle 
he understands the software 

[Ohio HD]

If you have a big difference in the closed throttle table from the main spark table it can get funky on idle during warmup.

who said anything about idle 
he understands the software 

Yes, I chased the "hunting idle" in the past. I understood what you meant, and where.

[1931jamesw]

If you have a big difference in the closed throttle table from the main spark table it can get funky on idle during warmup.

who said anything about idle 
he understands the software 

Yes, I chased the "hunting idle" in the past. I understood what you meant, and where.

I owed Jim something to groan about.

[joe_lyons]

What tuner is it?

I like adding timing to decell(15-20kpa) or closed throttle spark if avaiable.  Leaning out the afr table in the same kpa. Works for most.  Double check exhaust leaks also.  Decell enleanment is only effective when there is a delta change in throttle position from high to low= momentary effect only like with shift pop.

[Ohio HD]

Joe, It's TTS. I have no leaks at the exhaust, and the decel popping I have for the most part gotten rid of. But occasionally I get a "snap" "crackle" on decel.

[joe_lyons]

Joe, It's TTS. I have no leaks at the exhaust, and the decel popping I have for the most part gotten rid of. But occasionally I get a "snap" "crackle" on decel.

Sorry, I was directing to the OP/whetsel.m

[Ohio HD]

Joe, It's TTS. I have no leaks at the exhaust, and the decel popping I have for the most part gotten rid of. But occasionally I get a "snap" "crackle" on decel.

Sorry, I was directing to the OP/whetsel.m

[hrdtail78]

If timing is the answer, I like to address it in the main table.  It's really the only time that you are in that area. CTS table effect other things.i don't like chasing my tail or creating other problems.

I mention pw because some cals turn them
off on hard decel. 

[1931jamesw]

If timing is the answer, I like to address it in the main table.  It's really the only time that you are in that area. CTS table effect other things.i don't like chasing my tail or creating other problems.

+1 and was basically my point in my OP.

[joe_lyons]

What issues come about when altering the area changed to 30 here?

[7hogs]

Here is was I use for decel inleanment no popping issues did the same on my wife's bike and it the issue is gone

0.69
0.67
0.65
0.60
0.48
0.35
0.30
0.27
0.24
0.22
0.15
0.05

[strokerjlk]

What issues come about when altering the area changed to 30 here?

i give up. i cant think of one