Smelly exhaust

[acree25]

Does anybody have a sugesstion or a guess?

I've got a 4.5L 1989 Coupe Deville that has 130 thousand miles on it. Ive had it for seven months now. Whenever I come to a stop and the windows are down there is horrible rotten egg smell. Since I've bought it, I have changed the fuel filter, the oxygen sensor, the cat conv, and the air filter. There are no apparent leaks around the fuel injectors.

There only trouble code that comes up is E24 (VSS open circuit). I don't know if this would have anything to do with my exhaust smelling or my engine running rich.

So I took the car to the Cadillac dealer to get it diagnosed, but they just called me at the end of the day and told me that they couldn't find anything wrong with the car and didn't charge me anything. They suggested that I try using a different brand of gas because of sulfur content in the brand that I am using. I usually use Shell gas, but I have a hard time believing that this is the problem.

Thanks in advance for any ideas!

[98Concours]

I was going to suggest the same thing. Try a different brand of gas for a couple of tanks and see if the smell goes away.

Jeff

[JasonA]

Indeed, some formulations of gasoline have a higher sulfer content in them...or at least a higher level of SOMETHING that reacts with your catalytic converter to produce a sulfer-like odor.

I think a common misconception is that if you smell rotten eggs, it means something's wrong. If your car is running rich, that might be the case, but I also understand that in some situations, a perfectly normal and functioning converter will give off a sulfer smell during periods of high product conversion (like periods of WOT operation). It seems that no matter what kind of car it is (brand new Mercedes Benz or beat up Chevy Celebrity), you can always tell when the driver is "flooring it" because of that distinctive sulferesque olfactory sensation.

['60buickrod]

I'm pretty sure that is your catalytic converter. I bet that if you replace it that smell will disappear. Unless you live in a state that does not require emissions testing. If that is the case it should go away in just alittle while, because they actually serve little to no purpose. Hope that helps. seth huggins

[KenD]

It's probably your gas. I had the same stinky problem and I changed stations and viola, the problem was gone.

[SteveJ]

You changed one oxygen sensor but are there two on your 4.5? I know the 4.9's had one in each exaust manifold, front and back. . . and yes a bad O2 sensor really makes and engine stink.

[CaddyJack]

Your Cat converter will make a rattling sound when it is dying. If it is the cat converter - go to Midas - cheaper than a dealer and they will give you a lifetime warranty. (dealer told me to go there). Dealer cat job will cost more $ and no warranty.

[acree25]

The exhaust line on my car only has one O2 sensor and it is before the cat. conv. I have been noticing a rattling sound coming from underneath the car. AI was thinking that it could be a wheel bearing, but is it likely that it could be my cat. conv. making this sound?

I tried banging on the converter a couple of times with a rubber mallet, but there was no ratling present.