Crazy Exhaust fumes... Need HELP NOW!!!

I have a stock 350 in my burban, and just got the suspension done...  The Muffler had to be shortened so it is under the cab...  With the windows open, even on the highway, I get alot of heavy fumes coming in!  I took the truck to a muffler shop and they said there are no leaks!  I know i will get fumes any way, but these smell really bad...  Im sure there are a number of reasons why it smells so heavy, but can I get a list of reasons to know what I am dealing with?  its starting to get scary  because I wanna do a lot of east coast shows and I dont wanna pass out while driving!!!

Do you have a turndown on it, or is it just cut straight back?

it has a turn down.

Does it have doors on back or a tailgate.  Mine had doors and I never had any probs.  If it has the gate and you have the back window down it will draw air ( and fumes) in through the back.  Most likely though I would bet you have a someplace in the floor its getting in.  Doesn't take much.  Good luck with that, Carbon monoxide is not something to play with.  It builds up in your system and take a while for your body to clear out.  Be safe.

---------------------------------------------Originally posted by STLowburbanDoes it have doors on back or a tailgate.  Mine had doors and I never had any probs.  If it has the gate and you have the back window down it will draw air ( and fumes) in through the back.  Most likely though I would bet you have a someplace in the floor its getting in.  Doesn't take much.  Good luck with that, Carbon monoxide is not something to play with.  It builds up in your system and take a while for your body to clear out.  Be safe. ---------------------------------------------Actually when the windows are up, absolutely no fumes at all, so I know it comes through the window...  Being that the exhaust was shortened to end under the rear seats, it bring the fumes closer to us...  But When I picked up my truck it didnt have fumes like that, it actually started when I hit a bump.  I took it to a muffler shop and they said the only prob I had was the hanger broke and there was a tiny hole... They welded the tiny hole and fixed the hanger...  The truck became very silent which was good, but fumes are still high... I wanna know what could have caused it to be so bad.  Could the Cat have gone bad?  I didnt think my truck would have 1 since it is 30 years old but it does...  Any advice????

you should describe this bump a little more.. did you bottom out was it just harsh?

---------------------------------------------Originally posted by SledNeck91604you should describe this bump a little more.. did you bottom out was it just harsh?---------------------------------------------I guess u can say i bottomed out... what happen was there was a wierd bum in the road...  The truck went over it, but basicalluy the only thing i believe hit was just the muffler.  It wasnt like a speed bump, it was more like a bump u get by hitting ur head... in the middle of the street...  I guess it hit hard enough to make the muffler hanger come loose

You probably knocked a hole in the muffler and now its just by passing the muffler and coming out straight exhaust.  My brothers 4Runner did that before, he had a hole rusted in the top of his muffler and the truck always stank.

No holes the muffler shop showed me everything was fine... And the muffler didn't sound like it had a leak... Maybe the stuff in the muffler was bad after the hit?

Edited: 7/5/2009 10:22:05 AM by Big Dee

Maybe you should try another exhaust shop. If it doesnt come inside the truck when the windows are up ...........its obviously an exhaust issue and not a leak in the floor.  I'd get a 2nd opinion.  Or get someone from that exhaust shop to take a ride w/ ya w/ the windows down to show them what its doing.....