Quote:
Originally Posted by bishopts
Look at your fuel trims. Stft and ltft. Also your fuel ratio the tuner set it to.
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Yes.
I suspect you are rich.
I wrote my own explanation, then found this outstanding one on an Acura forum. I do not think is normal on your car, but I have hear this argument before, that brand new converters can be overly efficient.
Acura Knowledgebase Document
Acura Knowledgebase Document
Title/Subject: ROTTEN EGG SMELL (GOOD CATALYTIC CNVTR OPERATION)
KB Source: ATL-INFO
Code: 3810
Issue: 11/14/200
Application Matrix
MDX Start Yr 2001 End Yr 2002
Service Details
Problem: Unpleasant, rotten egg smell (catalytic converter operation)
Solution: None – this is a sign the catalytic converter is functioning optimally
Explanation:
The culprit ingredient responsible for the odor is hydrogen sulfide (H2S). H2S does not exist in fuel or oil, but it does come from gasoline during the combustion process. Nearly all gasoline contains organic sulfur compounds, with sulfer levels ranging from 30 – 2000 ppm (1000 ppm is the ‘legal’ maximum, and some areas are regulated to much lower levels – i.e. reformulated gasolines).
As combustion occurs, the organic sulfer compounds break down into simple compounds. If the engine is running lean, the sulfer compounds are likely to be expelled as a sulfer oxide (SO2). The catalytic converter changes the SO2 into sulfer trioxide (SO3). The SO3 reacts with the catalyst to form sulfates on the catalyst. If this occurs for a period of time (several minutes) and then the engine suddenly starts to run rich (slowing to a stop, hills, hard stopping, etc) the chemistry with the catalyst will change. The sulfates become unstable and form H2S, which is the unpleasant, rotten egg smell. The human nose can detect H2S in quantities much smaller than 1 ppm, so very little H2S expelled can create quite a detectable odor.
This effect is much more noticeable with the new vehicles due to the high efficiency of the catalytic converter. As the vehicle ages, the first reaction of the catalyst to be affected is the formation of H2S.
As Honda products do tend to run very clean/lean, this “smell” characteristic may be more common with our products than others. It is no cause for alarm, and in fact is indication the catalytic converter is working very efficiently. This smell, while unpleasant, does not contribute to atmospheric pollution.