Ok here is my dilemma... i have almost everything new on the car and it still stinks (like my clothes stink when the car is running in the garage and i am standing next to it)!!!. Anyways I have new spark plugs, wires, caps, rottors, coils, new MAF, blah blah blah. What else could be causing this stinker (beside the Cats, i know they need to be changed, but the smell is of HC more than the stench). Also, i think i have an exhaust leak at the junction where the cat meets the rear mufflers, is there anything i can do to wrap it there or close the leak?

Sincerely,
Khaled

 

Stinks after running how long? My car stinks like crazy when I fire it up in the morning to go to work, because of the cold start enrichment. I have to roll up my windows and turn the HVAC off as I back out of the garage and down the driveway. When I return from work it's hot, I pull into the garage and hop out, almost no smell at all.

 

I have to admit, it is probably at its worse when cold, but i think it still runs a bit stinkier than normal, at least than my Audi

 

Your Audi has a smaller engine with better management system and is 13 years newer..

 

The "sink" is more than likely the sulfur in your fuel. Not much you can do about it. I comes from the refining process of fuel. California is the only state that regulates the amount of sulfur in fuel. Every auto manufacturer has service buletins and info related to the sulfur content and smell not the fault of the automobile. I have delt with incresing complaints at the customer level about sulfur smells aka the " rotten egg " smell. In my opinion with barrell oil prices up at an all time high the refineries are
custting cost cornes and incresing levels. The only thing i could say would be the change brands for a few tank fulls and see if this helps.

 

....OOPPS......."stink " !!!! sorry

 

My car used to smell worse but it's mostly gone away. I have no idea why, except constant tweaking makes it run better...

 

Both my GTS and S4 smell when cold compared to newer cars. I'd say it was normal.

 

Sulphur in fuel can be the source of the odour as mentioned: if fuel is cleanly burned by the engine and both the O2 sensor and cat are up to spec, the more acrid odour of sulphur oxides (SOx) will be noted: if the cat is 'cooked', it is likely the redox reaction is further comprimised, leading to more hydrogen sulphide (H2S - aka 'rotten eggs') in the exhaust. Any of this is far worse in a cold engine for it is programmed to run rich - that's the underlying sweet smell of the exhaust ( well, it's sweet if you are addicted to high performance cars )

If the joint between the cats and center resonators ( or any other exhaust system joint) leaks, loosen the joint and apply a layer of the red RTV sealant made specifically for this -several brands available at any quality auto parts store at ~$7/tube - it works!

 

My car used to stink also and was very warm underneath. Dumped the cats in favour of the Motorsport X with a new o2 sensor and the smell and heat are gone.

 

A friend of mine left a plastic bag with fish under his seat after a fishing trip and forgot all about it.
Now..that was a stinker.
G