CEL following exhaust upgrade

[AMX2]

Hi guys.. just wondering if anyone has experienced this issue subsequent to an exhaust mod.... Ever since I upgraded the Xpipe (w/ deleted secondary cats) on my e90 m3 I kept getting CEL. I read the codes with the Carly code reader and the codes I got relate to Catalytic Converter Bank 1 and 2.

Is there a way to code this annoying CEL out so it doesnt keep popping up.. or is getting the car ECU tuned by a tuner is the only solution? Any ideas?

[roastbeef]

Probably screwed up the 02 sensors. Removing secondaries won't cause a CEL.

[Azurefire91]

Second the above, Check the O2 sensors on your primaries. Make sure when removing the xpipe the wiring wasn't damaged and clean the sensors if you possibly can to alleviate that as an issue. I recently deleted my secondaries as well on a seperate OEM xpipe I purchased and I have not had any CEL's after doing this mod.

[amrazM]

maybe post which xpipe you got? it probably doesnt have primary cats either.

[tdott]

What are the codes exactly?

Is your primary cat still in place?

[dpaul]

Originally Posted by AMX2

Hi guys.. just wondering if anyone has experienced this issue subsequent to an exhaust mod.... Ever since I upgraded the Xpipe (w/ deleted secondary cats) on my e90 m3 I kept getting CEL. I read the codes with the Carly code reader and the codes I got relate to Catalytic Converter Bank 1 and 2.

Is there a way to code this annoying CEL out so it doesnt keep popping up.. or is getting the car ECU tuned by a tuner is the only solution? Any ideas?

Assuming 1) the primary cats are in place
Assuming 2) you didn't damage post-cat O2 sensors or wiring

Then the most likely possibility is exhaust leak from damaged/reused/improperly installed gaskets between cats and your new X-pipe. If you've got cat insufficiency on both banks then both gaskets.

FWIW, when you are reporting a problem that involves an error code, always report the actual code, not just Carly's often incorrect interpretation. In any case there are a number codes relating the cats with quite different meanings and resolutions.

Finally, getting a tuner involved is the simplest solution to a cat related CEL. However, it is not really all that difficult to do it yourself with the proper tools, the most inexpensive being a Chinese clone of KessV2, about $75 or so on ebay, amazon or Alibaba. Basically, you read the DME via the OBDII port, obtain a binary file, make a couple of simple modifications with a hex editor and write it back. If you want to go that route, I'm happy to explain in more detail what you need to do. Obviously, it is simpler and safer to use a tuner, plus you get a tune! Just bust out another $600-$1000.

[pbonsalb]

Most tuners won’t do this. If you want to make simulators that plug into the 02, or a DIY 02 sim tune, you would have a market.

[dpaul]

Originally Posted by pbonsalb

Most tuners won’t do this. If you want to make simulators that plug into the 02, or a DIY 02 sim tune, you would have a market.

I'm not sure we are talking about the same thing but most tuners will disable the CEL that would normally occur when cats are removed, if you wish them to do so.

That does not mean that emission checking is disabled or that the car can pass inspection requiring either a cat ready flag or a tail pipe sniffer test. But most states allow one not-ready flag and don't specify which so you'll pass inspection with the CEL disabled. Doing this does require tools more sophisticated than WinKFP but it's not much of a problem.

By the way, I can make you a simulator that spoofs the signal from the post-cat O2 sensor in the S65 if you'd like. Or provide you a schematic diagram. It requires about $10 worth of simple electronic components. In the N54 world, they used to be popular but no one bothers any more (again, in most states) because 100% of the tuners will disable the cat CEL for you.

[NOUR1SHAWA]

can you provide me with simulator diagram

Originally Posted by dpaul

I'm not sure we are talking about the same thing but most tuners will disable the CEL that would normally occur when cats are removed, if you wish them to do so.

That does not mean that emission checking is disabled or that the car can pass inspection requiring either a cat ready flag or a tail pipe sniffer test. But most states allow one not-ready flag and don't specify which so you'll pass inspection with the CEL disabled. Doing this does require tools more sophisticated than WinKFP but it's not much of a problem.

By the way, I can make you a simulator that spoofs the signal from the post-cat O2 sensor in the S65 if you'd like. Or provide you a schematic diagram. It requires about $10 worth of simple electronic components. In the N54 world, they used to be popular but no one bothers any more (again, in most states) because 100% of the tuners will disable the cat CEL for you.

[dpaul]

Originally Posted by NOUR1SHAWA

can you provide me with simulator diagram

I've omitted C1, works fine. Start with pot set ~1K, make small changes to dial in.

But really this is unnecessary in any state (most) that allows one non-continuous ODBII monitor to be "not-ready". Very easy to disable O2 checking in software.