Have By Passed The Cat. On My Lly And Added Aero Turbine 3 1/2" Muffler And Tipe Pipe. Ever Sence Have Had Exhaust Smell In Cab. Have Checked All My Joints On The System And Have Found No Leaks, Even Took It To Mufler Shop And Still Found No Leaks. It's Really Noticable With The Heater On.
Anyone Else Have Same Problem???
Really Wondering If It Has Somthing To Do With The Cat. Bypass Affecting The Egr Valve.
Any In Put Would Be Great.
Thanks Smelly Cab From Utah!!!

I removed my cat and had the strong smell of fuel all around the truck, inside and out. I put cat back on..runs perfectly, no smell.

the way it was explained to me by the mechanic was... with no cat the egr doesn't know how much pressure is there thus doesn't know what to tell the computer, etc, etc and what you get is raw fuel in the exhaust.

Was Going To Add The Edge With Attitiude And Afe Stage Ii Intake And Was Thinking I Would Have To Much Heat With The Cat. So I By Passed It When I Did The Muffler. Wounder What Would Happen If I Blocked Off The Egr???

i have the same problem.removed cat in leau of 4" down pipe.mbrp exhaust. the smell is raw fuel.had cat off for about 10 months.just put it back on to get inspected. it does run better with it off.its quicker.and about 200 degrees cooler exhaust temp.as soon as i get it inspected i will take the cat back off.if my wife lets me

In the back of your cab, there are 2 vents. You could either duct tape them or find another way to block them off. I placed some packing foam in mine, cut to size. Seems to have reduced the smell of fumes coming into the cab.