[mattmasody]

So, to start this off, I installed an air intake back in January, everything was fine. I then installed a JB4, again everything fine.

March 6th I got the Evolution Racewerks catted downpipe installed and the very next day, the M Performance Exhaust installed. That night I noticed in Comfort mode and ESPECIALLY in Eco pro mode, my car would shake violently when accelerating moderately (30-40% pressure on gas pedal). At first I put it off for two months, after this period I started taking it seriously.

I immediately took off my JB4, same thing.
I reverted back to stock chargepipe, same thing.
I changed my Spark plugs, which one of them had oil on them, same thing.
I cleaned my air filter, same thing.

I ordered the OEM catalytic converter pipe and am going to have that reverted in about two weeks.

It's weird because it happens especially when i'm accelerating on freeway ramps between 1000-2000 RPM.

It's very hard to describe the feeling that the car makes. I can only describe it as it puts out power, then the next millisecond it doesn't. The car rocks forward and backward. This happened after I got the downpipe installed, it may be that.

Idk I'm just panicking because I don't want it to be anything serious or something in the actual engine that's going bad

[g20_shub]

Originally Posted by mattmasody

So, to start this off, I installed an air intake back in January, everything was fine. I then installed a JB4, again everything fine.

March 6th I got the Evolution Racewerks catted downpipe installed and the very next day, the M Performance Exhaust installed. That night I noticed in Comfort mode and ESPECIALLY in Eco pro mode, my car would shake violently when accelerating moderately (30-40% pressure on gas pedal). At first I put it off for two months, after this period I started taking it seriously.

I immediately took off my JB4, same thing.
I reverted back to stock chargepipe, same thing.
I changed my Spark plugs, which one of them had oil on them, same thing.
I cleaned my air filter, same thing.

I ordered the OEM catalytic converter pipe and am going to have that reverted in about two weeks.

It's weird because it happens especially when i'm accelerating on freeway ramps between 1000-2000 RPM.

It's very hard to describe the feeling that the car makes. I can only describe it as it puts out power, then the next millisecond it doesn't. The car rocks forward and backward. This happened after I got the downpipe installed, it may be that.

Idk I'm just panicking because I don't want it to be anything serious or something in the actual engine that's going bad

I would say make sure your downpipe is fitted properly ( no air leaks )

[MidnightShadow330]

Originally Posted by mattmasody

So, to start this off, I installed an air intake back in January, everything was fine. I then installed a JB4, again everything fine.

March 6th I got the Evolution Racewerks catted downpipe installed and the very next day, the M Performance Exhaust installed. That night I noticed in Comfort mode and ESPECIALLY in Eco pro mode, my car would shake violently when accelerating moderately (30-40% pressure on gas pedal). At first I put it off for two months, after this period I started taking it seriously.

I immediately took off my JB4, same thing.
I reverted back to stock chargepipe, same thing.
I changed my Spark plugs, which one of them had oil on them, same thing.
I cleaned my air filter, same thing.

I ordered the OEM catalytic converter pipe and am going to have that reverted in about two weeks.

It's weird because it happens especially when i'm accelerating on freeway ramps between 1000-2000 RPM.

It's very hard to describe the feeling that the car makes. I can only describe it as it puts out power, then the next millisecond it doesn't. The car rocks forward and backward. This happened after I got the downpipe installed, it may be that.

Idk I'm just panicking because I don't want it to be anything serious or something in the actual engine that's going bad

I had the same problem after installing VRSF downpipe. I have made a post about it many times. I know exactly what you mean, my car would also shake back and forth until it went down a gear. As long as the RPMs are above 2k it will never happen. Alsoto add, it never happens in sports mode either since a light tap of the pedal downshifts the car and holds the RPMs around 3k. I finally found a fix, but it was basically putting back my OEM downpipe. To this day I still don't know whether it was the installation or some cars have ECU issues that only come forth when the downpipe is installed. I plan to have it installed again and see what the problem is. Your best bet is to take it to another place and have someone see if it was installed correctly. There is a high chance it wasn't. However, do know if you put the OEM downpipe on your problem will go away. LMK if you have other questions.

[Kevin910]

Originally Posted by mattmasody

So, to start this off, I installed an air intake back in January, everything was fine. I then installed a JB4, again everything fine.

March 6th I got the Evolution Racewerks catted downpipe installed and the very next day, the M Performance Exhaust installed. That night I noticed in Comfort mode and ESPECIALLY in Eco pro mode, my car would shake violently when accelerating moderately (30-40% pressure on gas pedal). At first I put it off for two months, after this period I started taking it seriously.

I immediately took off my JB4, same thing.
I reverted back to stock chargepipe, same thing.
I changed my Spark plugs, which one of them had oil on them, same thing.
I cleaned my air filter, same thing.

I ordered the OEM catalytic converter pipe and am going to have that reverted in about two weeks.

It's weird because it happens especially when i'm accelerating on freeway ramps between 1000-2000 RPM.

It's very hard to describe the feeling that the car makes. I can only describe it as it puts out power, then the next millisecond it doesn't. The car rocks forward and backward. This happened after I got the downpipe installed, it may be that.

Idk I'm just panicking because I don't want it to be anything serious or something in the actual engine that's going bad

I just installed the same ER catted downpipe 2 weeks ago and also noticed this jolting back and forth. I was driving on the freeway and every time I would accelerate, it would jolt back and forth as if it was struggling. Please let me know if you found a solution to fix this, I am also worried it could affect my actual engine.

[dvniellee]

God someone please find a fix for this without taking out the downpipe.

[Myfaulttt]

i have a 330e with downpipe + opf off.
I started having this problem as soon as I made the exhaust changes. Even with the tune and turning off the sensors electronically it was still the same.
one day the tuner disconnected the oxygen sensor cable (I think) and it never happened again. I've been driving the car like this for 5000km and no warning in indrive

[mattmasody]

Originally Posted by mattmasody

So, to start this off, I installed an air intake back in January, everything was fine. I then installed a JB4, again everything fine.

March 6th I got the Evolution Racewerks catted downpipe installed and the very next day, the M Performance Exhaust installed. That night I noticed in Comfort mode and ESPECIALLY in Eco pro mode, my car would shake violently when accelerating moderately (30-40% pressure on gas pedal). At first I put it off for two months, after this period I started taking it seriously.

I immediately took off my JB4, same thing.
I reverted back to stock chargepipe, same thing.
I changed my Spark plugs, which one of them had oil on them, same thing.
I cleaned my air filter, same thing.

I ordered the OEM catalytic converter pipe and am going to have that reverted in about two weeks.

It's weird because it happens especially when i'm accelerating on freeway ramps between 1000-2000 RPM.

It's very hard to describe the feeling that the car makes. I can only describe it as it puts out power, then the next millisecond it doesn't. The car rocks forward and backward. This happened after I got the downpipe installed, it may be that.

Idk I'm just panicking because I don't want it to be anything serious or something in the actual engine that's going bad

I fixed the issue. I reverted back to stock catalytic converters, car runs amazingly smooth now.

[bquatt]

This is why you don't mess with the cats. A BMW should be a BMW and by that I mean a refined vehicle. Let's not rice them out. Unless it's your track vehicle, I don't understand that desire :

[Luke_M330i]

I had the exact same issue while cruising on the highway in 8th gear. I tried everything—replaced the VANOS, injectors, coils, reset the adaptations, checked fitment. Nothing worked. Then one day, I unplugged the downstream O2 sensor just to see what would happen, and the jerking completely stopped.

[mayvando]

Originally Posted by Luke_M330i

I had the exact same issue while cruising on the highway in 8th gear. I tried everything—replaced the VANOS, injectors, coils, reset the adaptations, checked fitment. Nothing worked. Then one day, I unplugged the downstream O2 sensor just to see what would happen, and the jerking completely stopped.

so do you just drive with an unplugged o2 sensor?

[G20Fun]

To add onto this 3 years ago I got a jb4 and did catless. Had the same exact issue in that rpm range. I did switch to a flash tune with O2 monitoring disabled, and it doesn’t have the same reaction. The only thing that may work is possibly an O2 bung, but even then I don’t know why that would fix it. There were multiple people on jb4 forums at that time that had the same issue, and none of us were able to resolve it without going back to stock DP. I didn’t try the bung but maybe someone has some experience.

[sutag22]

Hi guys, 430i with catless.

I’ve been facing the same issue as well, the exact same one and it was relieving to know that I wasn’t the only one. 🤣

I tried playing around with my xHP tune, but I realised that it had nothing to do with it, I was just wondering if it’s a good idea for me to just unplug the O2 sensor?

[Luke_M330i]

Originally Posted by mayvando

so do you just drive with an unplugged o2 sensor?

Yes, I’ve been driving without the rear O2 sensor for months now and haven’t had any issues. I’ve heard some people mention that it could affect long-term fuel trims, but I personally haven’t noticed any differences. That said, the best long-term solution is to get a custom tune.

[sutag22]

Originally Posted by Luke_M330i

Yes, I’ve been driving without the rear O2 sensor for months now and haven’t had any issues. I’ve heard some people mention that it could affect long-term fuel trims, but I personally haven’t noticed any differences. That said, the best long-term solution is to get a custom tune.

I’m considering actually doing that — did you unplug the whole thing off or did you unplug the one that connects into the ECU?

[Luke_M330i]

Originally Posted by sutag22

I’m considering actually doing that — did you unplug the whole thing off or did you unplug the one that connects into the ECU?

I unplugged the side that connects to the ECU and zip tied it, just make sure it’s the downstream sensor (it’ll be closer to the exhaust). If you’re using MG flasher for your tune, I believe they should have a custom tune available that fixes it if you contact support.

[sutag22]

Originally Posted by Luke_M330i

I unplugged the side that connects to the ECU and zip tied it, just make sure it’s the downstream sensor (it’ll be closer to the exhaust). If you’re using MG flasher for your tune, I believe they should have a custom tune available that fixes it if you contact support.

Alright, have you tried it without a tune though?
I have no plans to unlock my ECU and flash it.

[Luke_M330i]

Originally Posted by sutag22

Alright, have you tried it without a tune though?
I have no plans to unlock my ECU and flash it.

Yes this still works even if you’re not tuned, but I only had this weird stutter issue after changing the downpipe. If you’re having this issue on stock downpipe it might be something else.

[sutag22]

Originally Posted by Luke_M330i

Yes this still works even if you’re not tuned, but I only had this weird stutter issue after changing the downpipe. If you’re having this issue on stock downpipe it might be something else.

Yep, I got the issue because of a catless DP.

[Luke_M330i]

Originally Posted by sutag22

Yep, I got the issue because of a catless DP.

So yes it will fix your issue, it’s really weird but I think it’s related to the ECU version. Some ECU calibrations for the G20 don’t have this issue. We just got unlucky lol

[sutag22]

Originally Posted by Luke_M330i

So yes it will fix your issue, it’s really weird but I think it’s related to the ECU version. Some ECU calibrations for the G20 don’t have this issue. We just got unlucky lol

For real broo, i’ll try what you suggested and i’ll get back to you
Appreciated

[sutag22]

Luke_M330i

Yo bro, I just unplugged the O2 sensor and ziptied it the way you did it, it works like a charm. The car runs smoothly again, and I see no CEL.
Only a fault code I identified in the picture, code 12B304.

The rest has just always been there honestly.
Once again, thanks a lot bro.