rotten egg smell...help!!

[boxcartommie22]

i got a po430 code and found out the cat on the left bank was not working...so i had replaced all the cats (2 on each side) with one on each side high flow by car sound (magnaflow) put the sensor before and after the cats..these smell bad its been a week or more since i had this done..when i start it up when parked or over night the exhaust smells nice and sweet...this cars runs great and also that fixed the code....98 vic with 4.6...i replaced the following: new plugs motorcraft platinums,new maf, new fuel press. reg. new coils,and i use 87 conoco gas...are these new cats suppose to smell in this configuration with just one cat on each side?....advice on any other ideas would be helpful..

Post Extras:

 

[Mike_dup1]

The brand of fuel you are using can cause this (high sulpur content). Try anothe brand gasoline.

This is a common complaint with many vehicles.

Here is some info I found with a quich Google search.

quote:

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During normal combustion, the chemistry of the catalyst can change due to driving conditions. The ingredient responsible for the odor is hydrogen sulfide (H2S). The existence of H2S comes from gasoline during the combustion process. This process is considered normal, and is more noticeable with a CLEAN/LEAN running engine, like Hondas and Toyotas.
NOTHING can be done to prevent this, it is more likely to be noticable with a new vehicle due to the high efficiency of the cat converter.

So give it some time, put some use into your vehicle and your cat converter and when the cat converter is not running as efficiently as it was when it was brand new, the smell will subside.

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[JohnnyO]

Could be that somehow your air/fuel mixture isn't right or the new cats just need to break in.

 

[Jim Spahr]

It is generally the reaction of the sulfer in the gasoline and the cat. Change gas brands. The mechanic's theory is that Shell gas is the worst offender with higher sulfer content. Of course, it oculd be other things like the PCM dumping large amts of fuel or a plug not firing allowing raw gas to hit the cat, and so on. How is your gas mileage? Any MIL's indicated?

 

[c502cid]

Another thing to consider is a rich fuel mixture. If your car has a map sensor it's telling the ecu that it senses a high load and it is sending extra fuel into the motor to compensate for it. The smell is the give away your engine is running too rich and overloading the converters.

 

[RobWest]

It takes a while for new cats to wear in. If it does not, then you probably have a lean condition.

 

[boxcartommie22]

i get excellent gas milege and i have a brand new maf sensor....when i the car sits and then i start it the exhausts smells sweet so i fig its not dumping gas in the exhausts..

 

[boxcartommie22]

the rotten egg smell is gone..so it was the new cats breaking in..it smells nice and sweet..thanks to all for your suggestions