N51/ n52 new cats or o2 spacers for emissions???

Joshgoble4 · 11-23-2022, 03:11 PM

Hi everyone I am posting about codes p0430 and p0420 on my 2010 328i (with n51 but I doubt it’ll differ from n52 with this problem). These codes started a few months ago when I was having issues with the car stalling. Eventually I found the culprit was the fuel ekp module, and from that point on it has driven normally. I have also had this car for about 5 years so any difference in driveability is usually obvious. Now I’m here several months later, car runs great but can’t get rid of these cat codes. Codes are for both banks (p0430 and p0420) and all the inpa data looks normal to me. I figured if it was pre cat o2 sensors, the fuel mixture would be off, making the car run different. I replaced one of the post cat o2 sensors and still the codes are present for both banks. At this point I’m considering either some used eBay cats or o2 sensor spacers.

Need to figure out for emissions next month!

Lemme know what y’all think and I appreciate it in advance

Joshgoble4 · 11-23-2022, 03:15 PM

The first photo are the codes present but ignore the fuel pump code cuz the photo is a few months old. The second photo you can see all the o2 sensor voltages at the bottom which all look normal to me and don’t jump around that much

MOD.Works · 11-26-2022, 07:00 AM

Your catalytic converters are broken?
I have the same codes but I have catless headers. I also get the engine light.

Brian86 · 11-26-2022, 10:31 AM

Spacers didn't work for me

https://www.e90post.com/forums/showp...ostcount=21491

https://www.e90post.com/forums/showp...ostcount=21543

It only triggers to O2 sensor malfunctions shortly after starting the car after a brief stop, perhaps one or two hours. When the engine is still a warm but the cats are cold.

My cat's still work oK once they are hot, but they do not light off quickly enough before the engine starts running diagnostics in those conditions.

Joshgoble4 · 11-27-2022, 12:37 AM

Yea these two fault codes are exactly what I would expect to get with deleting your cats.

Also thanks for the input on spacers. This car is my daily and I want to keep it relatively reliable and stock and i have heard that spacing the o2 sensors can give you intermittent CELs. At this point I’d rather just replace the converters to pass emissions and to rid me of my service engine light. At this point I’d ask:

Does anyone know if there’s exhaust differences between n51 vs n52?

Just to make sure there’s no secondary cats or something else that could be triggering these error codes.

And also if I replace my cats I’ve seen used on eBay for decent pricing (but for all I know they might be garbage just like mine

)

So would y’all look into buying used cats or new, which cost as much as 1 months mortgage.

Any feedback appreciated and thanks for the previous replies

Brian86 · 11-27-2022, 12:48 PM

Meh, you're probably oK with used ones from ebay but it's always a gamble. Choose a reputable seller.

e9x are scrapped LOOONGGGG before the cats fail. It's not a common problem except for the cat delete folks.

The nail in the coffin for mine was severe liquid oil contamination around 280k (like, oil dripping out the exhaust tips contamination) due to the CCV system failing catastrophically.

I think mine would still be good at 340k but for the oil problem. We have another member here with 400k and the cats are good.

If your car doesn't have very high mileage you should probably look into an oil burning or fuel trim problem that caused them to fail prematurely.

Joshgoble4 · 11-28-2022, 12:05 AM

Yea that’s true cuz I don’t want to replace them and then have the new ones fail after a few months. Pretty sure it’s down to my ccv system. I investigated a few weeks ago by taking off the intake manifold and it did have quite a bit of oil inside so that’s gotta be my answer. I’ll probably overhaul the ccv to resolve the oil burning and then go with used cats off eBay. This will all take me a couple days but it’ll be worth it and I’ll be able to pass emissions.

Thanks for the help and I’ll report back with results after I do the work!

Also for anyone working with ccv on n52s I found this thread with loads of good info: https://www.e90post.com/forums/showthread.php?t=1033361

Thanks again!

11-23-2022, 03:11 PM	#1
Joshgoble4 New Member 0 Rep 10 Posts Drives: E90 328i Join Date: May 2022 Location: Atlanta, GA iTrader: (0)	N51/ n52 new cats or o2 spacers for emissions??? Hi everyone I am posting about codes p0430 and p0420 on my 2010 328i (with n51 but I doubt it’ll differ from n52 with this problem). These codes started a few months ago when I was having issues with the car stalling. Eventually I found the culprit was the fuel ekp module, and from that point on it has driven normally. I have also had this car for about 5 years so any difference in driveability is usually obvious. Now I’m here several months later, car runs great but can’t get rid of these cat codes. Codes are for both banks (p0430 and p0420) and all the inpa data looks normal to me. I figured if it was pre cat o2 sensors, the fuel mixture would be off, making the car run different. I replaced one of the post cat o2 sensors and still the codes are present for both banks. At this point I’m considering either some used eBay cats or o2 sensor spacers. Need to figure out for emissions next month! Lemme know what y’all think and I appreciate it in advance Attached Images
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11-23-2022, 03:15 PM	#2
Joshgoble4 New Member 0 Rep 10 Posts Drives: E90 328i Join Date: May 2022 Location: Atlanta, GA iTrader: (0)	The first photo are the codes present but ignore the fuel pump code cuz the photo is a few months old. The second photo you can see all the o2 sensor voltages at the bottom which all look normal to me and don’t jump around that much
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11-26-2022, 07:00 AM	#3
MOD.Works Private First Class 43 Rep 109 Posts Drives: BMW 130 Join Date: Nov 2021 Location: Europe iTrader: (0)	Your catalytic converters are broken? I have the same codes but I have catless headers. I also get the engine light.
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11-26-2022, 10:31 AM	#4
Brian86 Captain 638 Rep 766 Posts Drives: e36 M3, e91 325xi, N50 Xterra Join Date: Dec 2020 Location: Pittsburgh iTrader: (0)	Spacers didn't work for me https://www.e90post.com/forums/showp...ostcount=21491 https://www.e90post.com/forums/showp...ostcount=21543 It only triggers to O2 sensor malfunctions shortly after starting the car after a brief stop, perhaps one or two hours. When the engine is still a warm but the cats are cold. My cat's still work oK once they are hot, but they do not light off quickly enough before the engine starts running diagnostics in those conditions. __________________ Sometimes a bolt is just a bolt.
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11-27-2022, 12:37 AM	#5
Joshgoble4 New Member 0 Rep 10 Posts Drives: E90 328i Join Date: May 2022 Location: Atlanta, GA iTrader: (0)	Yea these two fault codes are exactly what I would expect to get with deleting your cats. Also thanks for the input on spacers. This car is my daily and I want to keep it relatively reliable and stock and i have heard that spacing the o2 sensors can give you intermittent CELs. At this point I’d rather just replace the converters to pass emissions and to rid me of my service engine light. At this point I’d ask: Does anyone know if there’s exhaust differences between n51 vs n52? Just to make sure there’s no secondary cats or something else that could be triggering these error codes. And also if I replace my cats I’ve seen used on eBay for decent pricing (but for all I know they might be garbage just like mine ) So would y’all look into buying used cats or new, which cost as much as 1 months mortgage. Any feedback appreciated and thanks for the previous replies
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11-27-2022, 12:48 PM	#6
Brian86 Captain 638 Rep 766 Posts Drives: e36 M3, e91 325xi, N50 Xterra Join Date: Dec 2020 Location: Pittsburgh iTrader: (0)	Meh, you're probably oK with used ones from ebay but it's always a gamble. Choose a reputable seller. e9x are scrapped LOOONGGGG before the cats fail. It's not a common problem except for the cat delete folks. The nail in the coffin for mine was severe liquid oil contamination around 280k (like, oil dripping out the exhaust tips contamination) due to the CCV system failing catastrophically. I think mine would still be good at 340k but for the oil problem. We have another member here with 400k and the cats are good. If your car doesn't have very high mileage you should probably look into an oil burning or fuel trim problem that caused them to fail prematurely. __________________ Sometimes a bolt is just a bolt.
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11-28-2022, 12:05 AM	#7
Joshgoble4 New Member 0 Rep 10 Posts Drives: E90 328i Join Date: May 2022 Location: Atlanta, GA iTrader: (0)	Yea that’s true cuz I don’t want to replace them and then have the new ones fail after a few months. Pretty sure it’s down to my ccv system. I investigated a few weeks ago by taking off the intake manifold and it did have quite a bit of oil inside so that’s gotta be my answer. I’ll probably overhaul the ccv to resolve the oil burning and then go with used cats off eBay. This will all take me a couple days but it’ll be worth it and I’ll be able to pass emissions. Thanks for the help and I’ll report back with results after I do the work! Also for anyone working with ccv on n52s I found this thread with loads of good info: https://www.e90post.com/forums/showthread.php?t=1033361 Thanks again!
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