Rotten egg smell and lumpy idle

[Danny DeVito]

First, do these things ever run right ? Last three days after starting fine the idle is going up down for a bout five seconds then settles. Driving is normal. If i turn the engine off and restart immediately it still does it. After three days of this. Now a dirty scummy smell has started, comes in through air vents but i can smell it especially under the bonnet at the gearbox end of the engine. Could it be my injectors leaking again after only fitting new seals about three months ago ? The smell is much different though to when my injector was leaking. That smell was the carbon cut your throat smell. This is more rotten egg type, not that i ever smelled a rotten egg that i can remember, but i think it would smell like this if i had. My air-con doesn't work either never has since i got it. Any ideas ?? Thanks

 

[zenman63]

The smell is the cat, over rich mixture going through.
why, could be anything.

 

[Oily Rag]

+1 for cat.

 

[BlackC55]

On a diesel?

 

[whitenemesis]

Rotten eggs, the air con...

 

[abecketts]

rotten egg smell is H2S hydrogen sulphide which could be the battery cooking itself, is the battery warm/hot?

 

[Danny DeVito]

On a diesel?

Why do you say this ? Is the cat operation different on a diesel ?

I've read a few threads about bacteria and a thought occured to me.

This bit :- Turn your heater controls up to max for the last 5 mins of your journey -every journey.This will dry the system out and you should not have that smell the next morning. -:

With the warm weather lately i open the cold vents for fresh air. The tempmatic buttons goes down to 18oC then it says Lo. At 18oC warm air still comes through. At Lo just cold air comes though. These last weeks are so warm that i have it a Lo an awful lot. Mayyybe the bacteria has started growing. It really stinks at startup and then fades away. So i will try get cleaner and see how it goes , and before that i will run the heater on full for a while.

It's not the battery either thats under the paso seat. The smell is slightly sharper than battery gas too. Thanks for the input so far.

Will bacteria grow without having used air-con ? MB head office ireland told me before thats it's very common growth. But i didnt know what he was talking about then.

Last thing is what about the idle. Now sometimes when i put into drive the car is chugging a bit for a short time . Are the two related or just coincidence ..Cheers

 

[whitenemesis]

I have my air con on Auto all the time, summer and winter. Never had any smells. You can get anti-bacterial sprays (from MB) to zap the system

 

[Danny DeVito]

I don't have an Auto button, it all seems a bit crappy really. I never had smells in my other cars though, Hyundai Trajet or Nissan Patrol. Is it peculiar to MB's ?

 

[kwakdonut]

The sulphur/rotten egg smell from a cat really only happens on petrol engines - its the sulphur contained within the petrol itself. I believe the cats on a diesel do a different job and the sulphur content of diesel is much lower than of petrol.

 

[yachtman]

On a diesel?

I thought that too whenI had my first merc diesel, however bothmy previous c sport and the clk occasionly smell /ed sulfurous when putting the car in the garage, seems more noticeable when the engine is neither fully hot or completely cold

 

[Spin_bowler]

I never had smells in my other cars though, Hyundai Trajet or Nissan Patrol. Is it peculiar to MB's ?

No. We've had five Audi's and the aircon stunk in all of those too.
My Passat and Golf did as well.

Perhaps it's a German thing.

 

[Iben]

My bets the Aircon. For my sins I'm a smoker, and as of today I am still allowed to smoke in my car but I have been reilable informed by some people that smoking in the car with the Aircon on recirculate will cause awful smells to be blown out. Dont ask me why, I dont even know if it true, could just have been a member of Ash winding me up LOL

 

[esox]

idle is going up down for a bout five seconds then settles.

rotten egg smell is H2S hydrogen sulphide which could be the battery cooking itself, is the battery warm/hot?

+1 for battery.
Could be charging system related.
Check voltage across battery terminals when engine is running.
Uneven idle could be alternator-related: loading the engine enough to drop idle speeds.

 

[lxi]

air con bacteria - particularly common if it's not been used.

You can buy the spray to cure in just about any motoring store, eg Halfords

 

[Danny DeVito]

+1 for battery.
Could be charging system related.
Check voltage across battery terminals when engine is running.
Uneven idle could be alternator-related: loading the engine enough to drop idle speeds.

I'll try check bat voltage tomorrow

 

[Danny DeVito]

I thought that too whenI had my first merc diesel, however bothmy previous c sport and the clk occasionly smell /ed sulfurous when putting the car in the garage, seems more noticeable when the engine is neither fully hot or completely cold

I think sulfur leaves a bit of a taste like the carbon does, makes you cough a little or you feel it in your nose. This just smells bad.

So with ign on and blower at 1...no smell...
Start car. smell after 3-5 secs and then gradually fades almost completely.

I will try get a can o' stuff and blow it in there on monday. It smells a lot when first started but not later on

 

[Danny DeVito]

So all sorted i think. I sprayed half a bottle of Dettol Anti-bacterial surface cleaner into the intake and and took off the dash and sprayed inside the air ducts and hey presto...Smell GONE!!!

 

[DRBC43AMG]

I always use the air control on full auto and never had a smell. Have you checked if your car has an fresh air pollen filter? If not get it changed!

 

[Danny DeVito]

I always use the air control on full auto and never had a smell. Have you checked if your car has an fresh air pollen filter? If not get it changed!

Not sure if i have an 'auto' function or even a pollen filter. If i have a filter i bet it's never ever been changed, i will check it out thanks