I know this has been posted before, but the search couldn't find it. I have about 1300 miles on my TMAX/AT install, running map 392. The bike is an '07 Road Glide with K&N 3909 intake and S&S SPO slip-ons, the rest is stock. I am running with the v4.6 firmware and have the Decel Fuel cut turned on. I haven't modified the fuel cut off points at all (yet). When down shifting, or just quickly backing off the throttle, I'm still getting some fairly bad popping and an occasional backfire.

I spoke to Zipper's tech support a while back and they said that the popping was caused by air being sucked back into the exhaust by the rapid throttle drop, causing the O2 sensor to read artificially high and the TMAX compensating by dumping extra fuel to the engine. I remember a while back someone posted about changing the zore throttle position AFR to something down in the 12's to fix this. Maybe I'm wrong, but if Zipper's explanation is correct, wouldn't having a desired AFR even lower than the base map cause even more fuel to be dumped in?? If the extra fuel is already causing the popping, how could even more help??

Does anyone have any suggestions that might help eliminate some of the popping?? I'm open to trying just about anything at this point.

Sorry about the long post, just trying to clear up some confusion on my part and, hopefully, bet the popping eliminated.

TIA,

Mike

 

I have been working out the same issue. I first leaned out (13.99) the settings from 0 to 14% and the popping got worse. What I have done is fattened up the 0 to 14% to 13.542 AFR and am not using the decel fuel at all. It has taken away 95% of the popping, I now get a little gurgle upon decel.

Give it a try.

 

Thanks, I'll give that a shot.

Mike

 

Do what you are doing, but go more. Try 13, or less.
Ron

 

try putting a more restrictive baffle on the left side pipe, or completely block it off, this should help significantly.

 

I'll second and third the above recommendations. I had bad popping until I took 0-14% TPS down to a 13.137 AFR. Eliminated all but a very rare, occasional pop. I'm not using decel fuel feature at all, either.

 

2007fltr,

My decel pops were (IMHO) caused by map 393. I switched to one of the 400-series maps (403 to be exact) and have had no issues since. I don't have a lot of faith in the 390-series and have heard more than once "decel pop" complaint about those maps. Rbabos can give you a better technical explanation but I reccomend finding a 400-series map that is close to your configuration and reloading.

Rick

Look at this thread: https://www.hdforums.com/m_3238788/tm.htm

PS: I am not using the decel cut feature and I do not get pops anymore, bike runs friggin' great!

 

Rick,

Thanks for the link. That's the thread I was searching for and couldn't find it.

As for the 400 series maps, the only one that uses the stock FL head pipe (412) is also set for a Red Shift cam. Would this be too far off from the stock cam to use it??

I'm going to reload the edited fuel maps tonight and test ride after work, assuming the damn rain stops.


Mike

 

Mike: If you are happy with the map otherwise, lower the afrs to 13 from the 14% throttle to 0.&nbsp\\; If you are experiencing high rpm pops then the decel function may need to be set accordingly. These solutions are at opposite ends of the scale, as the decel cuts fuel,&nbsp\\; and the 13afr adds low end fuel. Popping is from a perfect mixture which ignites in the pipe. by adding more fuel, it is no longer prone to&nbsp\\;explode as easily. Since adding more fuel to higher rpms creates other problems, mainly mpgs, the decel shuts the fuel off at specified rpms. No fuel, no pop. The time you spend at 14% throttle and under won't have much impact on mpg with such low rpms. I can't take credit for this info as TO BE FRANK was the first to my knowledge to post this info on the forum. Many have found it successful as a popping fix.
Ron

 

Like Koppster said - I switched to map 403 and I love it on my Dyna!!!!&nbsp\\; It was like night and day compared to map 393.