Cylinder misfires after downpipe change

BMW DIY Guy · 03-15-2019, 07:54 PM

Wooohoooooo!!!

Success! So THANK you to everyone for all of the info, feedback and suggestions. A full reinstall, with O2s torqued down and the lower V band installed properly and everything is amazing!

So no cylinder misfires as per the false (historical) positive led me down the wrong path at first, but it was the lower v band causing the POOF sounds and stumbles. She pulled clean and strong in all of the test runs.

thanks again all, this forum rocks!

TEST DRYVER · 03-16-2019, 01:59 AM

Quote:

Originally Posted by BMW DIY Guy

Wooohoooooo!!!

Success! So THANK you to everyone for all of the info, feedback and suggestions. A full reinstall, with O2s torqued down and the lower V band installed properly and everything is amazing!

So no cylinder misfires as per the false (historical) positive led me down the wrong path at first, but it was the lower v band causing the POOF sounds and stumbles. She pulled clean and strong in all of the test runs.

thanks again all, this forum rocks!

Excellent! That's good news! No actual car enthusiast likes to hear problems with their cars or mods. It seems like it's ok to spend money on mods and maitinence, but definitely NOT ok to spend money to fix what we broke =) the irony...

GPM · 03-16-2019, 12:38 PM

Ya know Stefan, I've heard there are these things called YouTube videos that supposedly show you how to do this stuff right.

You might want to check them out, just sayin...

BMW DIY Guy · 03-16-2019, 01:04 PM

Quote:

Originally Posted by GPM

Ya know Stefan, I've heard there are these things called YouTube videos that supposedly show you how to do this stuff right.

You might want to check them out, just sayin...

Hahahaha.. I know right?! *laugh* The false positive really threw me for a loop but the moment I got back under the car and could see that rear v band, I knew (at least one thing) what was wrong. 8)

Just had the thing slightly cockeyed on the top where I couldn't see it, and I dont think anywhere near tight enough. My new uber digital torque wrench that arrived this week did the job there.

bqik · 03-16-2019, 03:48 PM

Quote:

Originally Posted by BMW DIY Guy

Hahahaha.. I know right?! *laugh* The false positive really threw me for a loop but the moment I got back under the car and could see that rear v band, I knew (at least one thing) what was wrong. 8)

Just had the thing slightly cockeyed on the top where I couldn't see it, and I dont think anywhere near tight enough. My new uber digital torque wrench that arrived this week did the job there.

subscribed!

you give all the bad and good info.

what are your next steps for the 435i?

BMW DIY Guy · 03-16-2019, 04:18 PM

Quote:

Originally Posted by bqik

Quote:

Originally Posted by BMW DIY Guy

Hahahaha.. I know right?! *laugh* The false positive really threw me for a loop but the moment I got back under the car and could see that rear v band, I knew (at least one thing) what was wrong. 8)

Just had the thing slightly cockeyed on the top where I couldn't see it, and I dont think anywhere near tight enough. My new uber digital torque wrench that arrived this week did the job there.

subscribed!

you give all the bad and good info.

what are your next steps for the 435i?

Next up is a TuningTechFS HPFP, really excited for that as also prep for a turbo upgrade. I also have an Awron gauge system in route which will be fun!

I also am working on suspension in the future, with very likely Bilstein B16s and a BBK on the radar.

ceedawg · 03-17-2019, 07:22 AM

Quote:

Originally Posted by BMW DIY Guy

Next up is a TuningTechFS HPFP, really excited for that as also prep for a turbo upgrade. I also have an Awron gauge system in route which will be fun!

I also am working on suspension in the future, with very likely Bilstein B16s and a BBK on the radar.

Glad you fixed this

Have you tried ethanol yet and which turbo upgrade are you going with?

I was also advised to gap my plugs 22 to 25 with the stock turbo and high boost.

BMW DIY Guy · 03-17-2019, 07:26 AM

Quote:

Originally Posted by ceedawg

Quote:

Originally Posted by BMW DIY Guy

Next up is a TuningTechFS HPFP, really excited for that as also prep for a turbo upgrade. I also have an Awron gauge system in route which will be fun!

I also am working on suspension in the future, with very likely Bilstein B16s and a BBK on the radar.

Glad you fixed this

Have you tried ethanol yet and which turbo upgrade are you going with?

I was also advised to gap my plugs 22 to 25 with the stock turbo and high boost.

No E85 yet.. really focus my build on pump gas. I may throw in some octane boost come "test and tune" days in a few months.

The turbo I am hoping for is an unannounced product as of yet.. really really hoping there is big news in the next 30 days on that. 8)

bqik · 03-17-2019, 02:47 PM

Quote:

Originally Posted by BMW DIY Guy

Next up is a TuningTechFS HPFP, really excited for that as also prep for a turbo upgrade. I also have an Awron gauge system in route which will be fun!

I also am working on suspension in the future, with very likely Bilstein B16s and a BBK on the radar.

B16 is the first thing I did.

After 100.000miles with them I can confirm that sway bars is a must to replace in a F32.

regards

XutvJet · 03-19-2019, 10:48 AM

Is the car still driving/performing as it should? It seems odd to me that a minor exhaust leak downstream of the oxygen sensors would create CELs and poor driveability. A motor, ECU, sensors, etc. tend not to care what's going beyond the last line of analysis (i.e., the O2 sensors), especially a minor exhaust leak. No exhaust v-band, gasket, etc. is ever air tight and they all leak to some extent.

I wonder if the problem is/was simply a matter of a minor issue with the Stage 2 tune, colder plugs, the downpipe and it's less effective cats (compared to the HJS cats used by Fabspeed and HJS), and oxygenated winter gas. It seems like most that have driveability issues with tunes are those running downpipes and sometimes pushing an aggressive map.

03-15-2019, 07:54 PM	#23
BMW DIY Guy Brigadier General 3074 Rep 3,022 Posts Drives: 2019 M2 Competition Join Date: Jan 2017 Location: Maple Valley WA iTrader: (1) Garage List 2024 BMW M2 [9.80] 2017 BMW X1 [10.00] 2001 BMW X5 [10.00]	Wooohoooooo!!! Success! So THANK you to everyone for all of the info, feedback and suggestions. A full reinstall, with O2s torqued down and the lower V band installed properly and everything is amazing! So no cylinder misfires as per the false (historical) positive led me down the wrong path at first, but it was the lower v band causing the POOF sounds and stumbles. She pulled clean and strong in all of the test runs. thanks again all, this forum rocks! __________________ Check out my BMW DIY Channel on YouTube! E, F and G series projects from Active Autowerke, Bimmertech, Kies Motorsports, AvinUSA, Karbonius Composites and more! YouTube BMW DIY Guy 'Nimona' G87 M2 Build Thread 'Lillith' F87 M2 Competition Build Thread
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03-16-2019, 12:38 PM	#25
GPM Second Lieutenant 175 Rep 211 Posts Drives: 2015 335i Join Date: Mar 2016 Location: Arizona iTrader: (0)	Ya know Stefan, I've heard there are these things called YouTube videos that supposedly show you how to do this stuff right. You might want to check them out, just sayin... __________________ Mineral Gray - Active Autowerke Stage 2 - MPerformance Suspension - VRSF CP - CTS Turbo IC - Catted Fabspeed - Akrapovic - HRE FF15
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03-19-2019, 10:48 AM	#32
XutvJet Major General 5552 Rep 5,369 Posts Drives: 2011 Cayman Base, 2016 M235 Join Date: Mar 2016 Location: Kansas City iTrader: (-1)	Is the car still driving/performing as it should? It seems odd to me that a minor exhaust leak downstream of the oxygen sensors would create CELs and poor driveability. A motor, ECU, sensors, etc. tend not to care what's going beyond the last line of analysis (i.e., the O2 sensors), especially a minor exhaust leak. No exhaust v-band, gasket, etc. is ever air tight and they all leak to some extent. I wonder if the problem is/was simply a matter of a minor issue with the Stage 2 tune, colder plugs, the downpipe and it's less effective cats (compared to the HJS cats used by Fabspeed and HJS), and oxygenated winter gas. It seems like most that have driveability issues with tunes are those running downpipes and sometimes pushing an aggressive map. __________________ The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
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