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Discussion Starter · #1 ·
Hi all.

Just wondering how your exhaust smells?

My S38B36 has done some 130K km, the exhaust smell like many modern cars...a bit like rotten eggs and the exhaust is quite light, not "thick" so to speak

Most other E34's 6 cyl's that i have smelled have a more thick smell, almost like you get a bit thick in your throat when smelling it.

Was out looking at a '93 S38B38T today (poor thing :sad2: ), with 211K km on the clock, this also had a very thick exhaust.

So the question is, is my B36 running lean or are the others running rich?
My B36 is very smooth running, very responsive, and has from my opinion a good solid drag in low rpm's and take of as it's supposed to above 3750'is rpm.
Have yet to meet a car that haven't gone away in my rear mirror.

I get it down to about 10-11L/100Km on a long trip cruising at about 130-140Kmh, but have no problem getting it to use 1.7-2L if i really want to :hihihi: (Measured on consumed liters).
I struggle to get the 525IA (M50) to get the same low L/km on long trips.
Normal mixed driving around town and out on the freeway (looking out for the :cop: ) normally puts me in the 13-15L/100Km range

Any thoughts? Am i running Lean? or is my engine just well tuned and good working cats?
 

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Hi BoSJo ......I have just woken up after passing out whilst smelling my exhaust for 10 minutes ........

As my brain began to engage again , it occurred to me that the best way to see whether my car is running lean or rich is to check the condition of the spark plugs !
 

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Discussion Starter · #3 ·
ha ha ha davidoli, don't suck it in as if you where a vacuum cleaner, just sniff at it :hihihi:

Plugs are dry, and have a mouse Grey color.
Exhaust is pipes are a bit more on the black'ish color
 

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Plugs are dry, and have a mouse Grey color.
Exhaust is pipes are a bit more on the black'ish color
Sounds ideal to me BoSJo .......were the plugs to be extreme white with aluminium specs then it would be considered to be running lean .

Wet or sooty would suggest running rich .

I have decided to give up my exhaust sniffing ways before it becomes an addiction !
 

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Hi recently changed plugs on my 3.6 and they looked fine very light brown/clear and no sooty but my car smells rich, maybe normal:dunno:
 

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Mine smells rich as well. To the point it annoys me. Its off to get checked out next week. The last fault code check showed nothing wrong, but I suspect I may have a dodgy O2 sensor,
 

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When you guys say that your car smells rich , what exactly are you experiencing i.e An overfuelling / petrol smell and from where .....the exhaust or the block ?

D
 

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Discussion Starter · #10 ·
When cats go bad they can give off the rotten egg smell. Might want to get your cat checked out.
Hmmm, almost every never car has this smell in my experience....he he and i don't go around smelling at exhaust on every car that i see :) just noticed it.

But i have never smelled this from any E34 or E36 except from my own E34 M5
 

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Discussion Starter · #11 ·
When you guys say that your car smells rich , what exactly are you experiencing i.e An overfuelling / petrol smell and from where .....the exhaust or the block ?
My 525 smells fuel from the exhaust, even though the plugs looks fine, but there is a soot layer in the exhaust that is quite black and a bit sticky.
I will replace the O2 sensor and plugs just to be sure, but it's the same smell from most other M50 engines.

I have in one occasion experienced fuel smell in the cabin of my M5.
Hit full throttle in 2 gear for 2-3 seconds and then released the throttle while engaging the clutch.
A heavy fuel smell entered the cabin, so i stopped and checked everything in the engine bay, but no leaks.
Guess it was just some sort of push back of air/fuel :dunno:
 

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When you guys say that your car smells rich , what exactly are you experiencing i.e An overfuelling / petrol smell and from where .....the exhaust or the block ?

D
Mine smells rich from the exhaust but no rotten egg smell as it has been decatted, however i understand that the rotten egg smell is poor grade petrol ie cheap supermarket stuff with more sulphur in than more refined gear and when this hits the very hot cat it gives off that smell
 

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give it an italian tune and then check it

i.e stay in 3rd on the highway and run at about 4000 rpm for about 10 minutes and get it all heated up and then check it.
 

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Cor, if Jen caught you suggesting that she would eat anything as unhealthy as hob nobs, she would cut you up into little bits - probably to put you in some kind of salad!!
 

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I used to love the smell of my M5's exhaust. It smelled like biscuits.

Mmmmm, biscuits.
Sorry Sir, who are you?

You can just barge in here and start making posts out of the blue :hihi:
 

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My 525 smells fuel from the exhaust, even though the plugs looks fine, but there is a soot layer in the exhaust that is quite black and a bit sticky.
I will replace the O2 sensor and plugs just to be sure, but it's the same smell from most other M50 engines.

I have in one occasion experienced fuel smell in the cabin of my M5.
Hit full throttle in 2 gear for 2-3 seconds and then released the throttle while engaging the clutch.
A heavy fuel smell entered the cabin, so i stopped and checked everything in the engine bay, but no leaks.
Guess it was just some sort of push back of air/fuel :dunno:
Since I got my E34 M5 back from a service (Non-BMW), ive been smelling a lot of exhaust gases in the cabin.
Where can check for leaks ?
I've put on a new exhaust system 2 weeks ago.
Will the microfilter help ?
Is the car running to rich ?
 
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