(Solved) Excessive exhuast popping on decel all of a sudden.

[bmwfnatic]

Could have screwed up the injectors by cleaning them. New Bosch injectors cost less than one BMW injector. Great time to put in bigger ones. You have think, injectors operate in milliseconds. They could be a little slow by a few milliseconds which doesn't completely cause an issue but they aren't closing like they should. It's the one things that was touched in a way that will really damage them so I'd start there.

Bosch injectors are NLA though...

[AWE46M3]

I'm kinda "in for the learning" here, so pardon my ignorance. Is *any* amount of popping unacceptable? OP you say "excessive". I have a little popping I guess--SSV1 catted kit, 63.5mm dual pipe resonated S2 and race muffler, HTE tune. I get a little off throttle popping, but barely. I have to pay attention to it I guess. But, drives great!?

Are you tuned for light pops/burbles? Saw Hassan has that service listed (light pops all the way up to gun shot sounds) on his E46 Tune package.

[PSUEng]

Are you tuned for light pops/burbles? Saw Hassan has that service listed (light pops all the way up to gun shot sounds) on his E46 Tune package.

I don't believe so--I didn't ask for it and it never came up in discussion.

[Riley]

Could have screwed up the injectors by cleaning them. New Bosch injectors cost less than one BMW injector. Great time to put in bigger ones. You have think, injectors operate in milliseconds. They could be a little slow by a few milliseconds which doesn't completely cause an issue but they aren't closing like they should. It's the one things that was touched in a way that will really damage them so I'd start there.

I had the injectors cleaned, flowed, and synced by southbay fuel injectors at high recommendation from basically everyone in my area. The car ran the same with the injectors cleaned, the reason I was getting the rich code on bank 2 was due to a bad o2 sensor. And once i replaced the fouled o2 sensor that is when rich code wnet away and the burble began.

My main issue now is that the car will not set the o2 heaters ready no matter what. The heaters themselves on both o2 are confirmed good and so is the wiring in the harness. I just replaced the battery to see if maybe low voltage could be causing issues with the heaters. I am also going to be installing a afr gauge to see if the car is running rich still even with no codes present anymore. If the car ends up showing bad afr readings I am going to install a wideband sensor in each header so I can see it is is just one bank or not.

[jpiazzam3]

I noticed this once before as well. Shortly after one of my coils went bad.

[AWE46M3]

I had the injectors cleaned, flowed, and synced by southbay fuel injectors at high recommendation from basically everyone in my area. The car ran the same with the injectors cleaned, the reason I was getting the rich code on bank 2 was due to a bad o2 sensor. And once i replaced the fouled o2 sensor that is when rich code wnet away and the burble began.

My main issue now is that the car will not set the o2 heaters ready no matter what. The heaters themselves on both o2 are confirmed good and so is the wiring in the harness. I just replaced the battery to see if maybe low voltage could be causing issues with the heaters. I am also going to be installing a afr gauge to see if the car is running rich still even with no codes present anymore. If the car ends up showing bad afr readings I am going to install a wideband sensor in each header so I can see it is is just one bank or not.

You have to complete a drive cycle. 55mph for 15 minutes will turn the O2 monitors on and ready.

Do not go over 3k RPM’s getting onto the freeway. If you do, pull off and turn the car on/off before getting up to speed. Keep the OBD2 reader plugged in - you’ll see the O2 monitor light turn green between 10-15 minutes cruising at 55mph

save this graphic

[Riley]

I noticed this once before as well. Shortly after one of my coils went bad.

I put brand new coils & plugs in after this to make sure that wasn't the cause either.

[Riley]

You have to complete a drive cycle. 55mph for 15 minutes will turn the O2 monitors on and ready.

Do not go over 3k RPM’s getting onto the freeway. If you do, pull off and turn the car on/off before getting up to speed. Keep the OBD2 reader plugged in - you’ll see the O2 monitor light turn green between 10-15 minutes cruising at 55mph

save this graphic

This is exactly what I have tried numerous times now. O2 Heater monitors should set ready almost instantly but because the heaters refuse to set ready the o2 sensor will not either.

I have been able to confirm heaters are functional with mode 6 data but they refuse to go ready.

[Slideways]

Maybe reflash back to stock or try another ECU.

[AWE46M3]

Maybe reflash back to stock or try another ECU.

+1 , I’ve been thinking about this on and off all evening and it just occurred to me that reflashing the stock tune could do the trick. Logged on to drop the comment and you beat me to the punch 😄

My cruise control wasn’t working after installing the correct clutch switch and we reflashed the stock tune after verifying all the hardware and wiring was correct and it resolved the issue. Reasonable next step for OP to try

[Arith2]

Bosch injectors are NLA though...

Not stock size, bigger which always equals better.

https://polmaxracing.com/index.php/product/6-genuine-bosch-ev14-52lb-550cc-fuel-injectors-bmw-s54-3-2l-01-06-m3-01-02-z3m/

[Riley]

+1 , I’ve been thinking about this on and off all evening and it just occurred to me that reflashing the stock tune could do the trick. Logged on to drop the comment and you beat me to the punch 😄

My cruise control wasn’t working after installing the correct clutch switch and we reflashed the stock tune after verifying all the hardware and wiring was correct and it resolved the issue. Reasonable next step for OP to try

I will keep you guys posted.

PS just saw you earlier comment from a few days ago. The car isn't tuned for any burble at all. It only started to pop after changing the o2 and as of now I am chalking it up to being related to whatever is going on with preventing the o2 heaters from setting ready.

[Riley]

To those following...spoke with my turner this week the stock file he had given me wasn't actually the stock tune. I now have the car back on the original stock tune and the o2 heater & o2 sensors instantly set ready and all burble went away. So the issues I was having were definitely tune related and possiblly the cause of my o2 fouling out originally. Still waiting to hear back on when I can get the tune looked at on the dyno so we can data log and see what in the aftermarket tune was actually causing the issues

[EthanolTurbo]

To those following...spoke with my turner this week the stock file he had given me wasn't actually the stock tune. I now have the car back on the original stock tune and the o2 heater & o2 sensors instantly set ready and all burble went away. So the issues I was having were definitely tune related and possiblly the cause of my o2 fouling out originally. Still waiting to hear back on when I can get the tune looked at on the dyno so we can data log and see what in the aftermarket tune was actually causing the issues

What's the point? Just put a new good tune on it. There's no great scientific revelation to find out by wasting time and resources dynoing a bunk tune.

[Riley]

What's the point? Just put a new good tune on it. There's no great scientific revelation to find out by wasting time and resources dynoing a bunk tune.

I have access to a dyno so it cost me nothing 🤷.
Car was running fine for over a year and a half. Odds are the o2 was on it way out and somehow it caused a hiccup with the tune once it threw the rich code originally.

I just want to confirm it’s actually not running rich or lean when I flash back