[fiche335]

My 2009 335i has failed the MOT due to high CO levels. The limit is 0.2 and it was reading 0.3-0.4.

Car has CATless DP's, JB4, intercooler etc. Engine was fully warmed up immediately before the test. My tester is a good chap who I've used for years and he did everything to help me out but to no avail.

Before I get the original DP's refitted next week has anyone got any suggestions? It's being serviced on Saturday so I can get it on the diagnostic m/c if necessary I guess.

Thanks,

[windymissile]

Have a read of the thread here in the technical section. I have just had mine mot'd with no issues at all. Your emissions are 10x what mine were. The dp's should make little or no difference to an engine that is fully warmed up. I would look for other possible problems before looking at the dp's.

WM

[doughboy]

Hi fiche,

Much beer now it's warm than the 0.9% you mentioned yesterday .

Did he try both pipes like he should?

The fueling and lambda is controlled separately for cylinder bank1 and bank2, this means each exhaust can give different results.

Just get it checked on another machine, doesn't have to be an mot per say, a fiver should get it checked, just to make sure your man's machine is ok?.

[fiche335]

Cheers WM.

I've been in touch with the previous owner who was well known on here and he said it had previously passed without a problem. As I said it's being serviced on Saturday so I'll get them to run a diagnostic check to see if there's anything obvious. I don't want to put back on the original DP's if I can help it.

Anyone got any pointers on what might make the CO levels rocket like this?

[xenon]

You would think a dodgy MAF but that would show an engine warning light.

[windymissile]

There is no maf. Its a map controlled engine.

Wm

[fiche335]

Originally Posted by doughboy

Hi fiche,

Much beer now it's warm than the 0.9% you mentioned yesterday .

Did he try both pipes like he should?

The fueling and lambda is controlled separately for cylinder bank1 and bank2, this means each exhaust can give different results.

Just get it checked on another machine, doesn't have to be an mot per say, a fiver should get it checked, just to make sure your man's machine is ok?.

Yes, much better than yesterday, it was actually passing until about 10s before the end of the test.

Tried both banks like you suggested but they were about the same. I think you're right, I might try another machine

[doughboy]

Originally Posted by fiche335

, it was actually passing until about 10s before the end of the test.

Was it the idle or fast idle that it failed on?

The limit is still 0.2% for either, but it's strange that it changed like you said.

I take it the other things like Hydrocarbons and Lambda were ok?

[AlanYoro35i]

Originally Posted by fiche335

My 2009 335i has failed the MOT due to high CO levels. The limit is 0.2 and it was reading 0.3-0.4.

Car has CATless DP's, JB4, intercooler etc. Engine was fully warmed up immediately before the test. My tester is a good chap who I've used for years and he did everything to help me out but to no avail.

Before I get the original DP's refitted next week has anyone got any suggestions? It's being serviced on Saturday so I can get it on the diagnostic m/c if necessary I guess.

Thanks,

n55 or n54?

[zltm089]

Try another tester! I'm sure there are loads that will pass it for a fiver...

[doughboy]

Fiche,

I've done a lot of googling tonight, several PH users rate this stuff for helping pass MOTs with iffy CATs, cheaper than putting DPs back on...

http://www.amazon.co.uk/Cataclean-Ca.../dp/B002BVXM92

Also the "italian tune up" i.e. driving at 70mph in 3rd to get the CATs REALLY hot and burn soot off them.

[Zoki]

So does the 335i usually pass MOTs ok with the CATs removed?

[windymissile]

Originally Posted by Zoki

So does the 335i usually pass MOTs ok with the CATs removed?

Yep. Please see page 3 of this thread..

http://www.e90post.com/forums/showth...=950347&page=3

WM

[gangzoom]

Originally Posted by Zoki

So does the 335i usually pass MOTs ok with the CATs removed?

I think it depends a bit on the state of secondary cats, when I asked about fitting downpipes at Birds they informed me that removing the primary cats will shorten the life of the secondary cats...even Hi-Flow catted down pipes will at some point cause the secondary cats to fail prematurely. Though up until now I've not heard of a 335 failing emissions....but as these cars get older its bound to happen, but I'll be surprised that a 09 car would fail emissions due to falling cats

From memory the CO readings from my car was 0 (undetectable), thats on a 08 car with AR Hi-Flow cats, car driven less than 1 mile to the MOT station from a cold start.

[fiche335]

Thanks all for the input.

I've ordered a bottle of catclean just in case but I think it's perhaps pointing to something else. I'll post up after the service to see if anything was identified.

[Icekube]

it shouldn't pass with 0 cats, if it does, then the Map is fucked and the car is running lean as hell (or the tester just happened to have another car running near by...)

[fiche335]

It has got cats, its just got the Pre-cats removed

[doughboy]

Originally Posted by Icekube

it shouldn't pass with 0 cats, if it does, then the Map is fucked and the car is running lean as hell (or the tester just happened to have another car running near by...)

As said, 335i has 4 CATs, you only remove 2 up front for tuning purposes.

Anyhow, if you ran it lean enough to pass on CO it would fail on high lambda (too lean)..... that's the whole point of the test, to make sure CO emissions are correct at the same time as checking the air/fuel mix is also correct.

[Icekube]

Originally Posted by doughboy

As said, 335i has 4 CATs, you only remove 2 up front for tuning purposes.
.

i was thinking that was the case (not being completely cat-less) and makes sense as to how it should be passing with the main cats intact.

i had a set of 100cell sport cats on my S4 and that easily cleared emissions (it too left the factory with 4 cats) i would have thought the stock BMW main cats would be more than up to the job.

[fiche335]

Just a quick noob question. When coming back from being serviced the engine warning light came on. I was running in map 0 (JB4) which I rarely do. After hooking up my Bavtec I saw 29F4 & 29F5 codes. The way I read it is that in any other map I'm running autoclear which is why I don't see the error. In map 0 this is disabled so it's picking up the DP's. Can someone confirm I've got this right before I go down a blind alley thinking this might be the source of the emissions test fail?
Thanks.

[doughboy]

Yes googling says those are the emissions codes, and they will be popping up with the jb4 being turned off, takes a few miles sometimes.

What's the text description in bav tec?

Not sure what map others leave there's in for mot?

[windymissile]

I left mine in map 5. I think map 4 is standard tune but auto clear enabled.
I don't think it will make a difference to the emissions though..

WM