mrk1957

When sitting in traffic in my c5 coup, I get a really strong exhaust smell. Dosen't appear to be any exhaust leaks. I've searched this and haven't really found a clue yet. Is there a common issue that's causing this?

dadaroo

Never heard of that with a C5 except when the catalytic converters have been removed and you can get a fuel/exhaust smell.

mrk1957

Not sure about the cats yet. Maybe there is a leak and I guess I won't know for sure until I get my '98 up in the air.
Really, the fumes are so bad, they about run you out of the car.

aaronc7

Has it always been this way or recent development?

3boystoys

Or you got fuel with a lot of sulfur in it.

mrk1957

I've had it about 2 months. Wish I could answer your question for sure, but I don't recall this during test drive or soon after I bought it.
As far as fuel goes. I've filled up several times at different stations and problem is consistent.

3boystoys

Bet previous owner most likely removed the cats.

mrk1957

Why would removing the cats cause noxious fumes in the cabin?

3boystoys

Bad welds or any of the other connection points that may have been loosened or moved when they were swapped.

dadaroo

No cats may give your exhaust an unburned fuel smell but not drive you out of the cabin. You have an exhaust leak and it should be easy to find.

BigGun

Plain and simple.

mrk1957

Looks like.... or smells like..... I have found the problem. I had been getting the P1416 code, so I retrofitted the passenger side check valve. Took care of the code and the exhaust fumes in the cabin as well. My guess is the check valve was stuck open allowing exhaust back through the valve and leaking out the hose connections for the AIR circuit.