Problems with '98 Accord EX... EGR maybe ??

Hi all. I'm actually posting on behalf of a friend who has had nothing
but problems with her '98 Accord EX V6 couple. I'll try to stay on
topic and ask about only one problem this post, with more to follow
later most likely

Anyway, this car has under 100,000 miles on it (98,000 I believe) but
recently it has started to emit an odor that can best be described as
raw eggs. The problem is that it's not constant. I've personally only
smelled it once and the car was still relatively cold. She has had it
smell other times when it hasn't started to smell until the engine was
warm for quite some time. I smelled around the hood to see if I could
find out where the smell was coming from and after smelling around the
hood and then under the car, I determined it was coming from under the
front seats (underneath the car). Now with the doors closed, this
smell cannot be detected but once you open either door, the smell is
awful.

I did some research and many mechanic websites said that it could be
the catalytic converter but she told me that this part was recently
replaced on her car. After doing some more research, I saw that these
accords have a problem with their EGR system and I found out that this
system is somehow related to the exhaust system.

Could a clogged EGR valve (it's a valve, right?) be the cause of this
horrible, irregular smell? Again, the most troublesome aspect of this
problem is that the smell is not consistent at all. For example, we
drove her car all last night and didn't smell anything once.

Either way she's going to be taking it to a mechanic but I want her to
be prepared and be able to request the free EGR cleaning that she is
entitled to, if that is the problem.

Thanks!

 

One other thing... we both went ahead and asked our dads what we
thought was wrong and my dad agreed with me and also thought it sounded
like the catalytic converter. However, her dad suggested that it was
the engine's timing belt ? Is this possible? Could a bad timing belt
be emitting a smell of raw eggs (inconsistently)? Her car is almost at
the 100,000 mile mark but as far as I can tell, it seems to be running
smooth as ever. What would be the signs of an engine belt that needs
replacing? Or maybe this is something she should have done regardless?

 

A rotten egg smell is typically caused by gasoline with high sulfur
content. In some cases, it wreaks (or should I say "reeks") havoc with
the catalytic converter. Switch to a higher quality gasoline brand
(regardless of octane) and maybe run a container of fuel injector cleaner
in it too. The catalytic converter itself should be OK.

If there was a problem with the EGR system or the catalytic converter,
performance could be very sluggish and the computer would trigger an error
code (causing the check engine light to come on).

 

its the catalyst doing its thing. does she buy gas at the same place
every time? some gas may be more prone to the sulphur burning smell.

 

in some locations, [the gulf states] there's been a relaxation in
gasoline sulfur content restrictions. sulfur = bad egg smell. it'll go
away again when the low sulfur content rules kick back in. don't let
any dealer talk you into spending money.