335i smoke after full decat

[M3_e36]

Hey gents,

So my 1st mod to my car was decat the down pipe and removal of the secondary cats, car start smoking a bit bad after, white smoke no blue or oil smells, iv been monitoring the oil, not using any oil.

the smoke is normally when the car is medium temp and coming to a stop when driving the car does not smoke or when the car is at max temp(or not as bad) .

Is there anything I can do about it other than putting the cats back in the sound is intoxicating and love the response. It more like overfuel fumes.

Would hate to drive with the roof down and car is loaded with smoke.

Any help would be appreciated.

 

[akash]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

 

[M3_e36]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

 

[akash]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

Did you do any type of software to bypass the sensors that attach to the down pipe?

 

[M3_e36]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

Did you do any type of software to bypass the sensors that attach to the down pipe?

Not sure if they put foolers in as I have no check engine light, ran ipna codes and got code for catalytic conversation. Turbos was replaced under motor plan not too long ago, I'm thinking it might be the sensors reading wrong and overfulling, but want to be sure so then I'll get software.

 

[akash]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

Did you do any type of software to bypass the sensors that attach to the down pipe?

Not sure if they put foolers in as I have no check engine light, ran ipna codes and got code for catalytic conversation. Turbos was replaced under motor plan not too long ago, I'm thinking it might be the sensors reading wrong and overfulling, but want to be sure so then I'll get software.

Pm one of the forum sponsors assistance.

They will be able to sort you out.

Most guys that run the JB units first go the software route before the installing hardware.

 

[graan13]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

Did you do any type of software to bypass the sensors that attach to the down pipe?

Not sure if they put foolers in as I have no check engine light, ran ipna codes and got code for catalytic conversation. Turbos was replaced under motor plan not too long ago, I'm thinking it might be the sensors reading wrong and overfulling, but want to be sure so then I'll get software.

From what I've read/heard it sounds like something to do with sensor by-pass and the system incorrectly managing things.

 

[M3_e36]

I would like to see the responses to the above.

Im also curious to know if its just because the system is less restrictive allowing the exhaust gasses to escape more freely.

If I had to know I wouldn'tve removed it, I know most guys just do downpipe but I took away my secondary ones as well so I basically fully decatted. Maybe it's time for jb4

Did you do any type of software to bypass the sensors that attach to the down pipe?

Not sure if they put foolers in as I have no check engine light, ran ipna codes and got code for catalytic conversation. Turbos was replaced under motor plan not too long ago, I'm thinking it might be the sensors reading wrong and overfulling, but want to be sure so then I'll get software.

Pm one of the forum sponsors assistance.

They will be able to sort you out.

Most guys that run the JB units first go the software route before the installing hardware.

Shot bro will do, will see if there others that experienced the same or got so feedback for me

 

[KrS24]

I'm in the same boat.
Have a JB G5.
Where can I get Cat foolers from?

 

[Sleeper135i]

Could be your turbo seals or a problem with your PCV valve.
Get checked out by a tech.

I've got full de-cat and no smoke at all, ever.

 

[hoosain]

sounds like valve stem seals to me
smoke on deceleration

 

[George Smooth]

In most cases the cat masks the problem of faulty turbo seals. Once removed it becomes evident.
Sometimes the lambdas are either put back incorrectly or damaged in the process. There is a specific torque they need to be connected at and if over tightened the crystals inside them break.

 

[akash]

OP says he had turbos installed not too long ago under MP.

Could it still be turbo seals? causing the issue?

 

[M3_e36]

In most cases the cat masks the problem of faulty turbo seals. Once removed it becomes evident.
Sometimes the lambdas are either put back incorrectly or damaged in the process. There is a specific torque they need to be connected at and if over tightened the crystals inside them break.

Could it still be the seals even if no blue smoke oil fumes or oil lost.

Next on my list was a carbon clean and pcv.

As the car got 120ks on I wouldn't like to know how the build up looks

---

sounds like valve stem seals to me
smoke on deceleration

Yeah sounds about right, funny thing is after driving it hard and when she is nice and warm doesn't smoke that bad more like a normal decatted car.

 

[Kish2604]

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

 

[Ralf*]

I see this post was started today

in my experience, apart from the more serious issues other posters have mentioned above

after we fit a new system, there is usually a bit of smoke, mainly due to the protective coating applied to the various pipes, that starts to burn off, and this creates a bit of smoke for the first few hours

 

[akash]

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Hi Kish2604

Is it an easy component to replace?

 

[M3_e36]

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Thanks PCV is next on my list, ok so the foolers silumators or mini cats are not needed but wouldn't it be best to get one isn't the sensors reading out if it's picking up no cats at all?

 

[Kish2604]

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Hi Kish2604

Is it an easy component to replace?

which component?

---

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Thanks PCV is next on my list, ok so the foolers silumators or mini cats are not needed but wouldn't it be best to get one isn't the sensors reading out if it's picking up no cats at all?

only option on PCV is the Rob beck version as the dealer doesn't sell replacement ones, its apart of the new valve cover itself, PM Revo@rennzport for one as I remember him having stock,

the o2 sensors that read the fuel mixture are the pre cat sensors, whether you got catted pipes or catless pipes it makes no difference to the 02 sensors... they still read the same...

the post cat sensors are there to measure catalyst efficiency and they will create the code that you seeing...they however have no effect on fuel mixtures and trimmings,

edit... get a JB4 and turn on auto clear, it will sort all this out for you...

 

[M3_e36]

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Hi Kish2604

Is it an easy component to replace?

which component?

---

its 70% the pcv valve is cooked, 10% the valve cover gasket, 10% a cracked valve cover ( near the oil filler) or 10% the turbo's...

I would search in that order for your gremlim, the SA spec n54 will not throw an engine light for catless downpipes therefore a cat fooler is not needed. you will get codes stored in the dme which does not affect performance.

Thanks PCV is next on my list, ok so the foolers silumators or mini cats are not needed but wouldn't it be best to get one isn't the sensors reading out if it's picking up no cats at all?

only option on PCV is the Rob beck version as the dealer doesn't sell replacement ones, its apart of the new valve cover itself, PM Revo@rennzport for one as I remember him having stock,

the o2 sensors that read the fuel mixture are the pre cat sensors, whether you got catted pipes or catless pipes it makes no difference to the 02 sensors... they still read the same...

the post cat sensors are there to measure catalyst efficiency and they will create the code that you seeing...they however have no effect on fuel mixtures and trimmings,

edit... get a JB4 and turn on auto clear, it will sort all this out for you...

---

Ok this definitely narrowed it down for me, as the valve cover gasket I replaced 2 months ago, there not a drop of oil around there, either pcv or turbos.

Might just get OCC one time.

Jb4 is calling my name but just want to get this sorted.