awful smell

[RV Wizard]

We rarely traveled with the windows open but would on occasion get the bad smell scenario. Found that I would loose the water in a trap. Wife would get up and run water in all the traps and the smell would go away.
Comes down to finding the actual problem and then you will know how to fix it.

[Ol'Joe]

Besides keeping the P traps full, I make sure there are a couple of inches of water in the toilet bowl too. I found that just the little water that's left after a flush was not enough of an odor barrier even on flat roads. The consant sloshiing around causes the seals to become exposed and the low pressure air caused by the open windows sucks the fumes out of the bowl. I also mounted one of those fancy dancy wingy looking vent covers on the roof and that seems to help a lot too.

[old man]

I think I found the problem with the awful smell in the coach when traveling. The gray water vent pipe was not connected to the tank. Had a hard time connecting it in the tight space but finally got it. Will be a few weeks before I can give it a test but I bet that will do the trick.
I really appreciate all of the replies and suggestions.

Enjoy lfe and safe traveling to all