F30 330D N57 Pre Cat 02 sensor replacement

mrbensam · 03-22-2024, 11:58 AM

Thought I would make a quick post about replacing one of my 02 sensors

My power delivery was a bit rough and when idling the engine would rock almost like a misfire and the engine sounded rougher than my brothers does

After scanning my car with ISTA I had 2 codes for the pre cat 02 sensor - 287500 and 287100 both relating to the pre cat 02 sensor

After clearing the codes a few times they kept coming back. I used one of the functions in ISTA to test it and it revs your engine a bit and shows you a few fancy graphs and basically confirmed it was faulty

I replaced it quite easily after cutting my hands to bits haha. After replacing it I cleared all the adaptations using ISTA because it tells you to do so

Now the car doesn’t shake when idling and the power delivery is also 1000 times smoother. If you have the same issue maybe this post will help you. I couldn’t find anything about this so thought I would share my experience 🫡

TurboWeasel · 03-23-2024, 05:35 AM

Good stuff. I thought it would be covered in oil from your other thread, so maybe not the turbo then.

mrbensam · 03-23-2024, 09:45 AM

Quote:

Originally Posted by TurboWeasel

Good stuff. I thought it would be covered in oil from your other thread, so maybe not the turbo then.

So did I mate haha, I still have no idea where my oil is going. I'm just topping it up and hoping for the best at the moment! Indy garage did say they couldn't see any oil in the exhaust or downpipe so fuck knows whats going on

TurboWeasel · 03-25-2024, 11:02 AM

Quote:

Originally Posted by mrbensam

So did I mate haha, I still have no idea where my oil is going. I'm just topping it up and hoping for the best at the moment! Indy garage did say they couldn't see any oil in the exhaust or downpipe so fuck knows whats going on

Gotta be the valve guides/seals or piston rings then

Shame it's not easy to get a borescope into a diesel engine as you would soon see what's what!
N57s don't normally suffer from cylinder wall scoring though unless an injector has failed and bore washed it for 1000s of miles.

See if your indy can do a leakdown test for you.

03-22-2024, 11:58 AM	#1
mrbensam Enlisted Member 11 Rep 46 Posts Drives: F30 330D M Sport Join Date: Feb 2024 Location: Liverpool iTrader: (0)	Thought I would make a quick post about replacing one of my 02 sensors My power delivery was a bit rough and when idling the engine would rock almost like a misfire and the engine sounded rougher than my brothers does After scanning my car with ISTA I had 2 codes for the pre cat 02 sensor - 287500 and 287100 both relating to the pre cat 02 sensor After clearing the codes a few times they kept coming back. I used one of the functions in ISTA to test it and it revs your engine a bit and shows you a few fancy graphs and basically confirmed it was faulty I replaced it quite easily after cutting my hands to bits haha. After replacing it I cleared all the adaptations using ISTA because it tells you to do so Now the car doesn’t shake when idling and the power delivery is also 1000 times smoother. If you have the same issue maybe this post will help you. I couldn’t find anything about this so thought I would share my experience 🫡 Attached Images
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03-23-2024, 05:35 AM	#2
TurboWeasel Major 794 Rep 1,013 Posts Drives: BMW 330D Join Date: Nov 2022 Location: UK iTrader: (0)	Good stuff. I thought it would be covered in oil from your other thread, so maybe not the turbo then.
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