Installed Catless Downpipes

Dosturbos · 06-02-2012, 08:21 AM

I just had my mechanic install Catless Dp's on my 08' 135i AT with Burger DCI and JB4.
I am running map 2 on the JB4. Also, the DP's are made by VRSF.
Here is what is happening. When I start the car up, there is an extremely harsh idle for about 10 seconds, then then the car idles fine.
When I go to drive the car everything feels pretty good for about 15 minutes (good power, good throttle response) then the car starts to stutter and buck. The service engine soon light is on.
My mechanic ran a diagnostic, the car is definitely throwing codes for the O2 sensors, but this is normal if you just switched to Catless Dp's I presume?
I have tried resetting the ECU, driving on map 5 which is supposed to be the autotuning map for the JB4, but the car keeps stuttering and bucking after 15 minutes of driving.
Anyone have similar issues after installing catless DP's?
What should I be looking into to fix this problem?

Thanks in advance,

Ed

1speedbike · 06-02-2012, 09:32 AM

Do you have the code autoclear on?

Dosturbos · 06-02-2012, 10:03 AM

I don't have autoclear on, but I think I know what's up. I just talked to my tuner. I think the O2 sensors at the turbo Hotside need to be swapped.

06-02-2012, 08:21 AM	#1
Dosturbos Lieutenant 55 Rep 467 Posts Drives: 2017 F48 X1 MSport Join Date: Mar 2012 Location: Medford, MA iTrader: (1)	Installed Catless Downpipes - Need help. I just had my mechanic install Catless Dp's on my 08' 135i AT with Burger DCI and JB4. I am running map 2 on the JB4. Also, the DP's are made by VRSF. Here is what is happening. When I start the car up, there is an extremely harsh idle for about 10 seconds, then then the car idles fine. When I go to drive the car everything feels pretty good for about 15 minutes (good power, good throttle response) then the car starts to stutter and buck. The service engine soon light is on. My mechanic ran a diagnostic, the car is definitely throwing codes for the O2 sensors, but this is normal if you just switched to Catless Dp's I presume? I have tried resetting the ECU, driving on map 5 which is supposed to be the autotuning map for the JB4, but the car keeps stuttering and bucking after 15 minutes of driving. Anyone have similar issues after installing catless DP's? What should I be looking into to fix this problem? Thanks in advance, Ed
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06-02-2012, 09:32 AM	#2
1speedbike Brigadier General 732 Rep 3,274 Posts Drives: 2022 X4 M40i, 2008 135i Join Date: Jun 2008 Location: MKE iTrader: (15)	Do you have the code autoclear on? __________________ 2022 X4 M40i - 2008 135i - 2015 F700GS On Order - 2024 i4 M50 Scruffy's gonna die the way he lived... Mmhm.
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06-02-2012, 10:03 AM	#3
Dosturbos Lieutenant 55 Rep 467 Posts Drives: 2017 F48 X1 MSport Join Date: Mar 2012 Location: Medford, MA iTrader: (1)	I don't have autoclear on, but I think I know what's up. I just talked to my tuner. I think the O2 sensors at the turbo Hotside need to be swapped.
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