[Brucey335i]

Hey guys. Took my car on a road trip today about 220 miles. When i was about half way i noticed a shutter top end 1800-2200 rpm under VERY light acceleration.. soon as i pressed firmer it went away.... plugged my scanner up... (never got a CEL) cause I'm a nut when i hear any kind of noise... i noticed a active and a shadow fault for the o2 sensor post cat... is there a fuse for this! Or should i jump right into a o2 sensor 07 e90 335i

[mweisdorfer]

Originally Posted by Brucey335i

Hey guys. Took my car on a road trip today about 220 miles. When i was about half way i noticed a shutter top end 1800-2200 rpm under VERY light acceleration.. soon as i pressed firmer it went away.... plugged my scanner up... (never got a CEL) cause I'm a nut when i hear any kind of noise... i noticed a active and a shadow fault for the o2 sensor post cat... is there a fuse for this! Or should i jump right into a o2 sensor 07 e90 335i

That could be it. How old are your post cat O2 sensors?

What mods do you have?

When I think of a shudder in acceleration, I think of LPFP or the sensor associated with it.

[Brucey335i]

Originally Posted by mweisdorfer

That could be it. How old are your post cat O2 sensors?

What mods do you have?

When I think of a shudder in acceleration, I think of LPFP or the sensor associated with it.

Just did downpipes this month.. i have a charge pipe and forge diverter valves running Mhd stage 1 93 octane car drove absolutely fine until i drove today.. mind you. Car still pulls and there's no CEL i just noticed the shutter and went anal about it as usual.. just checked the fuse under the hood and it is showing good

[mweisdorfer]

Originally Posted by Brucey335i

Just did downpipes this month.. i have a charge pipe and forge diverter valves running Mhd stage 1 93 octane

Reset the adaptations for the for the O2 sensors both upstream & downstream.

Report back

[Brucey335i]

Originally Posted by mweisdorfer

Reset the adaptations for the for the O2 sensors both upstream & downstream.

Report back

Is there a way to reset them separate pretty sure Mhd just resets them both same time.

[Brucey335i]

Originally Posted by Brucey335i

Is there a way to reset them separate pretty sure Mhd just resets them both same time.

They are reset. Car drives normally isn't getting a boost cut or going into limp mode.. even during the initial diagnosis... the only reason i know the code is active is because i check it through the Mhd flasher. Car hasn't thrown a check engine, stalled or anything of the sort.. just feel the studder intermittently

[mweisdorfer]

Originally Posted by Brucey335i

Is there a way to reset them separate pretty sure Mhd just resets them both same time.

Not that I'm aware of. I wouldn't worry about that. You want all 4 O2 sensors to work on the same beat.

In my case, I reset all 4 and I don't have excessive smoke coming out of the tail pipes every once in a while.

[Brucey335i]

Originally Posted by mweisdorfer

Not that I'm aware of. I wouldn't worry about that. You want all 4 O2 sensors to work on the same beat.

In my case, I reset all 4 and I don't have excessive smoke coming out of the tail pipes every once in a while.

I haven't seen smoke smoke... at all.. no smell of gas either. I'm gonna be driving the car back the other 220 in a few days so I'll see how she acts then.. i reset the codes and the adaptations...

[mweisdorfer]

Originally Posted by Brucey335i

I haven't seen smoke smoke... at all.. no smell of gas either. I'm gonna be driving the car back the other 220 in a few days so I'll see how she acts then.. i reset the codes and the adaptations...

You might not since you still have your secondary cats. I don't though. Your O2's are acting up since you changed the parameters in which they work. You needed to reset them so the DME knows how to utilize them with the new hardware.

[Brucey335i]

Originally Posted by mweisdorfer

You might not since you still have your secondary cats. I don't though. Your O2's are acting up since you changed the parameters in which they work. You needed to reset them so the DME knows how to utilize them with the new hardware.

I did reset them. I haven't reset them since i did the downpipes.. they are reset now. I will know more when i drive it more. Haven't moved it a mile since i reset the adaptations

[type-dRew]

Owners manual states the o2 sensors are wear items and should be replaced every 100k.

Id stick to that especially when tuned. If they aren't brand new, id update them all.

[mweisdorfer]

Originally Posted by type-dRew

Owners manual states the o2 sensors are wear items and should be replaced every 100k.

Id stick to that especially when tuned. If they aren't brand new, id update them all.

I got 159,000 out of the post cat O2 sensors. I replaced my original pre-cat O2 sensors at 122,000 just to be proactive, and it was a "while I'm in there deal" when I did my oil pan gasket. They are extremely accessible when the subframe is out.

I did replace both pre-cat O2 sensors when I did my down pipes this spring and put MHD on the car.

I found that resetting the adaptations for all 4 sensors got rid of 90% of any smoke I was producing. I am completely catless. No secondary cats. I was producing a fair amount of smoke periodically with no real rhyme or reason at low RPM's (under 55mph, and my pre-cat O2 sensor on the rear was not liking the excess smoke. Sometimes, I got smoke & other times no smoke :

Not anymore. Reset the adaptations and no smoke to speak of really. This is true even in park sitting for a minute or two or at a stop light.

Yeeeee cousin!

OP if you're experiencing stuttering, etc. it isn't the post cat O2s....just because you got a shadow code for one doesn't mean that's the issue.

If it continues, you'd be better off looking at the normal wear items which usually cause similar symptoms: plugs, coils, injectors, etc.

[mweisdorfer]

Originally Posted by FCobra94

Yeeeee cousin!

OP if you're experiencing stuttering, etc. it isn't the post cat O2s....just because you got a shadow code for one doesn't mean that's the issue.

If it continues, you'd be better off looking at the normal wear items which usually cause similar symptoms: plugs, coils, injectors, etc.

I'd start looking at the LPFP sensor. Maybe the LFFP. 72psi is the magic number, and it should fluctuate. You can use MHD gauge to check and see.

[dpaul]

I don't believe you've said what the exact code number is.

Also, if you installed your stage 1 tune before you put the DPs on, is it possible that you did not select the MHD option for DPs?

Still, agree with other posters, a post-cat issue is unlikely to account for your part-throttle stutter. Logging with MHD is the best way to get useful information about engine operation.

[mweisdorfer]

All post cats do is monitor what the pre-cats are doing (making sure they are functioning properly)

It doesn't matter if you have downpipes and are only on stage 1 or 1+.