Gas...

[07TrailyLS]

I'll get right down to it guys. When I start traily up whether it's first morning start or randomly throughout the day my exhaust smells like gas pretty bad. Judging on how well the engines always ran and how good of mileage I get I chocked it up as being normal... what are your thoughts on this? Is this normal or do I have for example a injector putting too much gas into a certain cylinder?

 

[Mounce]

Or maybe a lazy cat

 

[07TrailyLS]

So you don't think it's something I should be threatened about mounce? Within the next couple weeks I actually planned on gutting my cat and putting a flow master or magnaflo muffler in while I was down there.

 

[Mounce]

Well i think it's a normal smell at cold start. It's running a little rich and the cat isn't up to temp so it's not working efficiently. Sounds normal

 

[Simon01]

Well i think it's a normal smell at cold start. It's running a little rich and the cat isn't up to temp so it's not working efficiently. Sounds normal

I'd agree with that, mine smells gassy on a cold startup too.

 

[shovenose]

Just got my 02 Envoy with the 4.2 as well and even though it runs perfect and the [extra expensive california certified] cat is fairly new [meow] it does smell pretty gassy at a start. My 2007 Colorado which has the 2.9 engine (same engine family as the TB/Envoy) also smells really bad like gas when starting cold in the morning. Worse than my 95 Suburban with 175K on the 350 V8 did when I had it... but nothing is wrong with it and since both vehicles pass California smog tests it must be normal.

 

[Sparky]

Cold start is a little smelly, yeah.

 

[psa55]

Sorry to revive this old thread. I read a lot of them tonight. I've got the same rich type gas smells on most starts, even when warm on my 2008 TB, with 226 000 kms. I did have a bad thermostat for a while a couple years ago. I was thinking about potential CAT issue. I'll have it tested hopefully tomorrow. Would a universal Magna or other 3" catalytic converter be okay? I've read lots about people not being happy with aftermarket parts mated to the 2.75" exhaust system. How much trouble would I create if I choose to gut it other than the CEL?

When I looked at the Catalytic Converter assembly, I noticed two circular shapes on the pipe. The service manuals on here indicated the rear such shape was the Cat. Is the forward shape closer to the exhaust manifold just a resonator similar to what is found at the rear?

I am due for a muffler. I see lots of Walkers around on the web,but am again worried about the performance. I'll price an OEM one out too.

Thanks!