I back my truck in my garage every night. I start it in the morning and immediately pull it out. If I walk back into the garage my nose and eyes burn from the exhaust fumes. It smells like the engine is really running rich. I don't see any smoke coming out the tail pipe and there is no visible smoke in the garage. My engine doesn't burn any oil. It idles good and run great. I use fuel injection cleaner regularly. I pulled all the plugs and they look like new.
When I turn the ignition key the engine immediately starts. The engine is only running about 5 seconds until I drive out of the garage. The smell is worse when the weather is colder.
After idling in the driveway for a few minutes I put my nose near the tailpipe and running rich smell is gone.
When I come home with the engine warmed up and back into the garage I leave the engine running and sniff the tailpipe and can't smell anything except hot air. There is really no smell to the exhaust.
So, the really rich exhaust fumes only occur when the engine is started after sitting overnight and the smell only occurs for a few minutes then goes away.
Anyone else experience this? Is this normal or acceptable for 96k miles.

 

cold starts are open loop which is a little richer. when the engine warms up and hits closed loop the O2's help lean out the gas appropriately.

you might try turning the key over but not starting the truck to let the little heaters in the O2s heat them up a bit before you start up and see if that cuts it down a bit. Otherwise, it's a normal occurrence.

 

This is 100% normal. The PCM is programmed to give you an overly rich mixture for start-up and cold idle. That is what you are smelling.

+1 Squirrels. (did not refresh before posting).

 

I'm wondering if the exhaust fumes that burn my eyes and nose are concentrated because they are contained in my garage OR
something is not right causing the mixture to be richer than it should be?

 

FWIW, I've noticed the "fumes" after starting up ice cold in my driveway for several minutes until engine temp comes up. One sure sign of running rich is a black, sooty tailpipe. If you don't have that, then it's normal.

 

You should smell it when it's -20 out. Just like tonight is going to be. Hooray for Fargo!

 

LOL, it would have to be one powerful stink to smell it at -20.

 

You have to be quick, before the snot freezes in your nose lol