So, I have started having an issue of a fuel smell coming from the vicinity of my charcoal canister/rear of the fuel tank. It has only happened twice to my knowledge, at least to a point where I smelled it from my cab. It lasts about 10 minutes or so then the smell goes away. I also noticed the DMTL pump appeared to be running. My understanding of the system is that the DMTL pump checks for leaks, while the truck is off. So it seems my problems are three fold, vapors not being purged to the engine, the DMTL pump running while the truck is running, and a leak on my fuel system and the DMTL system not detecting it.

Has anyone else had a similar situation?

 

Does this typically start when you fill up?

 

No, both time I was around half a tank, while I was off-roading, also while climbing in elevation. I know my tank pressure will rise with an increase in altitude, but I assumed that's what the evap system is for is to vent that into the engine. None of the other vehicles I was trailing with had any issues

 

I would be suspicious of the tank seal if it has not been done already. This has come up before a few of times. The tank would probably need to come out to access it right? There is a big tangle of hoses behind the tank fill, it is possible one also has rotted in two as well, probably worth a look.

Tom R did post some pictures up in his project thread if I remember correctly.