[135i]

I have a currently tuneless N54 with catback exhaust and catless downpipes. Upon full throttle my car hesitates and then runs really rough (afr at around 20 something) and I'm in limp mode. Restart car and I'm cool until I get on it again. My 02 sensors are bad because of the catless exhaust. Are these limp modes causing any damage to the engine?

Could reinstalling my V5 get rid of this issue or do I need new 02 sensors? Won't they just get fouled up again? My car is running like shit and it's getting really tiring.

Thanks for the help

[Brey335i]

What happened to your COBB tune?

I have run mine tuneless with catless downpipes before and the only problem was the check engine light.

Try installing the tune again and see if it goes away. I doubt it will though. Did you have the V5 in again lately?

Last time my car threw limp modes when I got on it was when I didn't install the V4 right and a pin was bent...

[135i]

Originally Posted by Brey335i

What happened to your COBB tune?

I have run mine tuneless with catless downpipes before and the only problem was the check engine light.

Try installing the tune again and see if it goes away. I doubt it will though. Did you have the V5 in again lately?

Last time my car threw limp modes when I got on it was when I didn't install the V4 right and a pin was bent...

I still have it. Just my car hasn't been running well since I put my catless downpipes on. I know my 02 sensors are bad (the dealership told me so). I'm just wondering how I can get my car back to running normally again.

[135i]

I'm getting all these limp modes and I'm not sure why.

PS I'll be in Austin tomorrow

[Brey335i]

Bad O2 sensors can cause limp modes so that seems to be your problem.

I would take out the downpipes and take it to the dealership to have the sensors replaced. If you were closer to me then I'd do the swap for you. It's not a good idea to go in for service with catless downpipes. Also make sure you remove any kind of tune

[Brey335i]

Originally Posted by 135i

I'm getting all these limp modes and I'm not sure why.

PS I'll be in Austin tomorrow

Just googled it. Several people have had limp modes when their O2 sensors go bad.


Cool, if you wanna bring the car by I can definitely put it back to stock for you so you can go in for service. Your catback exhaust shouldn't be an issue

[135i]

Originally Posted by Brey335i

Just googled it. Several people have had limp modes when their O2 sensors go bad.


Cool, if you wanna bring the car by I can definitely put it back to stock for you so you can go in for service. Your catback exhaust shouldn't be an issue

Awesome bro I'll drop you a line tomorrow!