by PhreakdOut » Fri Aug 24, 2007 12:15 pm
This is my theory on the cause of the smell:
>> High sulfur content in the fuel. Sulfur is commonly found with petrolium and is difficult to refine out in the process of making gasoline. Cheaper refiners will do the minimum required to pass EPA regulations. More on that later.
Since sulfur does not burn in the combustion process. It is expected to pass through to the tailpipe emissions. The problem is that sulfur is attracted to noble metals. (The platinum, palladium and rhodium in the catalyst substrate. ) So the sulfur will coat the substrate until it forms bonds with hydrogen mollecules and becomes "heavy" enough to break free of it's bond to the substrate. This forms Hydrogen Sulfide. (H2S) This is your "Rotten Egg Smell."
EPA regulates the sulfur in gas, not because of the smell but because of the formation of H2SO4. (Sulfuric Acid or "acid rain"). The cerium and zirconium wash coat on the converter substrate is intended to retain oxygen mollecules. ( Promoting the fomation for C02 and H20. ) So you can see how easy it is to form H2SO4.
>> In the past couple years, Toyota had a silent recall on the 2004+ vehicles for the sulfur smell. I don't know if it went all the way back to 2000 models. The silent recall simply was a different service part number than the production part number. The new service part number had a different converter welded into the assembly. The new converter had a different washcoat to reduce the formation of H2S. Toyota would recommend to the customers to change fuel stations. (Stop buying the cheap stuff. Not the octane rating, just the brand.)
Stop by your dealers part manager and ask if there are two part numbers for the converter on your Solara. (Or even better, send a pm to Reggie / NVDIS1 and ask him to look into it.) If there is a part in the recall campaign, then you might get it for free. (Installed) The dealer will not know directly about the silent recall. I believe there is nothing written on it and this is all voluntary on Toyota's part. Reggie will be able to find the details. Unfortunately, in the case of the recall, it wasn't on an older car. Customers complained about the smell right away. (So the washcoat was VERY prone to forming H2S even with small traces of sulfur found in fuel.)
Like I said above, it takes a lot to get the sulfur to release from the substrate. So it could be a couple thousand miles before it's all out. The first thing you should do is change who you get your fuel from before the substrate has any more deposits in it.
Good Luck,
-- The Phreak
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