Misfire impairing exhaust emission on all 8 cylinders

[Black.m3]

Hi,

First is it normal to have misfires & a CEL after 2 months on all cylinders if we replace an OEM exhaust by an IPE F1 front pipe with sport cats + IPE F1 x pipe + valvetronic mufflers ?

I have a rough idle at cold ONLY, there is no more issue when i drive the car & when i start again also, it does at cold uniquely.
No loss of power or performance, the OEM exhaust is re installed and those codes which are hard to solve appears always.

Any help would be appreciated.

2B4E Misfire impairing exhaust emission at several cylinders
2B42, 2B43 etc to 2B49.

I had also just one time the 27B1 and it never reappeared.

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[Black.m3]

Nobody ?

[Redd]

Check the obvious stuff? Ground strap, exhaust ring gaskets. If you already have the stock exhaust back on the car, clear the codes and try driving around without the intake plenum. Simultaneous 8 cylinder misfire is normally an intake-side issue, maybe an air leak.

[Black.m3]

Originally Posted by Redd

Check the obvious stuff? Ground strap, exhaust ring gaskets. If you already have the stock exhaust back on the car, clear the codes and try driving around without the intake plenum. Simultaneous 8 cylinder misfire is normally an intake-side issue, maybe an air leak.

Thanks for your answer.
We made a smoke test in the intake, we haven’t seen an air leak somewhere..

[Redd]

Drive it without the plenum. If misfires stop at least you know its somewhere in the plenum/intake.

Smoke test are not accurate. When I had a plenum air leak, I smoke tested it 3x and water tested it 1x. Came out OK. Later found the leak happened only when it was under vacuum.

[Black.m3]

Originally Posted by Redd

Drive it without the plenum. If misfires stop at least you know its somewhere in the plenum/intake.

Smoke test are not accurate. When I had a plenum air leak, I smoke tested it 3x and water tested it 1x. Came out OK. Later found the leak happened only when it was under vacuum.

The replacement of the exhaust with x pipe & front pipe with sport cats can makes all this strange of issues like the misfires impairing exhaust emissions on all cylinders ?
Because i putted back the oem exhaust and i still have these issues..

[DrFerry]

Possibly a bad primary 02 sensor and/or weak battery. At rest the battery voltage should read 13.3V. IF it is low (~12.6V) then strange emissions codes may happen, the clock will also start to run slowly and other odd codes can appear.

[DrFerry]

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[Black.m3]

Originally Posted by DrFerry

Possibly a bad primary 02 sensor and/or weak battery. At rest the battery voltage should read 13.3V. IF it is low (~12.6V) then strange emissions codes may happen, the clock will also start to run slowly and other odd codes can appear.

Concerning the battery I have a bosch 100 ah but not a 95 ah AGM start and stop, do i need to replace mine with the AGM maybe ?

But the car starts with just a rough idle, and i can drive it normal after, and going faster there isn't a issue.

So the issue isn't from the exhaust system at first ?

Btw i changed the O2 sensor without a reset of adaptations, i still have the issue. I ll do it soon.

[DrFerry]

Originally Posted by Black.m3

Concerning the battery I have a bosch 100 ah but not a 95 ah AGM start and stop, do i need to replace mine with the AGM maybe ?

But the car starts with just a rough idle, and i can drive it normal after, and going faster there isn't a issue.

So the issue isn't from the exhaust system at first ?

If the new 100ah battery was not registered to the DME then the car "thinks" it's only a 95ah. Hence it may not be charging fully from the alternator. It's only a small difference but these cars are rolling cyborgs and need the correct steady state voltage at rest to operate correctly. Get your new battery registered to the DME using ISTA or at the Dealership as that might be all that's needed.

The exhaust system might have caused some codes to be retained in the DME/ECU memory. Charge the battery, then clear the codes, make sure all 4 O2 sensors are installed and connected securely.

[Black.m3]

Originally Posted by DrFerry

If the new 100ah battery was not registered to the DME then the car "thinks" it's only a 95ah. Hence it may not be charging fully from the alternator. It's only a small difference but these cars are rolling cyborgs and need the correct steady state voltage at rest to operate correctly. Get your new battery registered to the DME using ISTA or at the Dealership as that might be all that's needed.

The exhaust system might have caused some codes to be retained in the DME/ECU memory. Charge the battery, then clear the codes, make sure all 4 O2 sensors are installed and connected securely.

Okay so it's better to take an AGM, the oxygen sensors has been installed properly but i need to go at the Dealership to make a reset of adaptations for the O2..
Unfortunately the M3 E92 has a special repair system when we change some parts of it.. not like the E46.

[DrFerry]

AGM means "Advanced Glass Matt". It is a newer technology than traditional lead acid batteries. IF your car has start-stop that system puts stress and strain on the battery, alternator and starter motor. Consequently, I recommend you install and use the correct type of battery your came with from the factory and that is AGM. Your Dealership might be able to code (register) the specs for an non AGM battery BUT I'm uncertain of that since ISTA may not have non OEM choices for battery registration specs.

I believe Start-Stop can be turned off using the small switch which is part of the start-stop bezel.

[Black.m3]

Originally Posted by DrFerry

AGM means "Advanced Glass Matt". It is a newer technology than traditional lead acid batteries. IF your car has start-stop that system puts stress and strain on the battery, alternator and starter motor. Consequently, I recommend you install and use the correct type of battery your came with from the factory and that is AGM. Your Dealership might be able to code (register) the specs for an non AGM battery BUT I'm uncertain of that since ISTA may not have non OEM choices for battery registration specs.

I believe Start-Stop can be turned off using the small switch which is part of the start-stop bezel.

Yes my car has the start and stop, i always disable it when i drive the car.

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[Redd]

Many people have replaced the AGM batt with normal lead-acid with no issues. It should not be the cause for your problems. Forgetting to code a new batt also will not cause misfires

Removing your cats without a tune will cause emissions CEL but should not cause misfires.

Again, remove your plenum and drive it and see if the misfires still occur.

[DrFerry]

Originally Posted by Black.m3

I have a rough idle at cold ONLY, there is no more issue when i drive the car & when i start again also, it does at cold uniquely. No loss of power or performance, the OEM exhaust is re installed and those codes which are hard to solve appears always.

.

Originally Posted by Redd

Many people have replaced the AGM batt with normal lead-acid with no issues. It should not be the cause for your problems. Forgetting to code a new batt also will not cause misfires. Removing your cats without a tune will cause emissions CEL but should not cause misfires. Again, remove your plenum and drive it and see if the misfires still occur.

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Perhaps I misunderstood. I thought he wasn't actually getting any misfires. He mentioned he has no loss of power or performance but merely getting the codes thrown. Hence, I thought it might be a low voltage battery issue. Forgetting to code a new battery may cause the battery not to be charged properly and low battery voltage can cause all sorts of gremlins. Agreed a tune is needed to remove the CEL if or when the Cats are removed. Good idea to run it and drive it without the plenum and see if the codes go away.

[Black.m3]

Originally Posted by DrFerry

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Perhaps I misunderstood. I thought he wasn't actually getting any misfires. He mentioned he has no loss of power or performance but merely getting the codes thrown. Hence, I thought it might be a low voltage battery issue. Forgetting to code a new battery may cause the battery not to be charged properly and low battery voltage can cause all sorts of gremlins. Agreed a tune is needed to remove the CEL if or when the Cats are removed. Good idea to run it and drive it without the plenum and see if the codes go away.

My issue is only at cold, rough idle for 10-15 secs + misfires impairing exhaust emission on several cylinders (on all)

I never made a tune with the IPE F1, and i installed the front pipe with sport cats + x pipe which according to IPE it should not trigger the CEL, and doesn't need a tune only if you go cat-bypass (catless)
And i putted back oem exhaust with always the same issue.

So to go step by step, for IPE my issue isn't related to the installation of the exhaust and for them it's a fuel or engine verification..
But what it's strange is that i had these fault codes after 2 months from the moment i installed the exhaust.

I never had these codes before to install the exhaust system, but if I'm not mistaken I noticed a slight irregular idle sometimes at cold start without codes or CEL before the installation of the IPE.

[stefan_e36]

the same problem( - https://www.m3post.com/forums/showthread.php?t=800514
as I found at forum , there are 3 or 2 variants of solving this
1.

Originally Posted by RBB

My car starting doing that this fall as the temps got colder in the mornings. The idle would bounce around during the cold start sequence for a couple seconds.

As usual, Mike is correct. I had ESS send me another version of my tune with cold start removed and I haven't had any problems since.

2.

Originally Posted by Sean05

Ive been using Techron since day one and have not use any other gas station in my M3 and its been 4 years 76k miles and the only problem on idle i had within 76k miles was

1. fuel low pressure sensor (REPLACED) fixed the issue
2. bad gas recently (idle at 700 then drops to 400/500 and almost stall thens go back to normal) keep in mind that it does not go up more than 700 rpm... filled it full tank of Chevron 91 and a Techron bottle and it stopped.
so im guessing its working.

BMW 13539899007
3. Fuel Tank Vent Valve 13907838281
https://www.m3post.com/forums/showthread.php?t=1148243
BMW 13907838281

As for me, the most true for your situation is variant 2
I have the same problem, with my friend's car, and we will check all this variants

[OneSickM]

OP @Black.m3, were you able to find what is causing issue?

I am having the same issue and cannot find what is causing it.