Evap Can Service Tube?
 

2000 E250 w/5.4, 285K miles currently

I'm chasing a Lean Bank #1 & #2 so I'm fingering every inch of any vacuum tube I can find. I will replace the PCV and both ends of that tube to the throttle body---the valve is OEM to the truck. :)

I notice the Evaporator Canister tubing running to the back of the van is crusty or crumbly to the touch. The test port is located on the transmission dipstick tube mount to the cowl panel. It doesn't seem to be connected by another other than spring clamps so obviously not under too much pressure or vacuum, no fluids flowing through it. I'm sure it's 20 feet or so long. Is it anything special or would any good grade of automotive hose similar diameter be okay for this use?

I don't think this is related to the Lean Bank issues but it might be a good idea to renew this part of the emissions system.

Any help or ideas or experience with this tube would be greatly appreciated.

TIA :-X22

I would recommend a rubber rated for fuel line if possible. Even though there should be no fuel in the line, it is always a possibility. It is low pressure, maybe just a few PSI from tank pressure, but nothing like the EFI fuel lines. I know that the PCV rubber hose ends are known to crack and leak vacuum as well as you may even have a dirty MAF sensor filament. If you haven't cleaned the MAF, they make a MAF spray cleaner, but I always just use brake parts cleaner, because it doesn't leave a film like some carb cleaners can. I just spray the thin filaments and let them air dry. They break easily, so I never touch them.
Good luck and I hope you find the cause soon.

I will indeed be using some sort of fuel handling rated tubing---need upwards of 13.5' according to Ford. I'll get 20' and need the Y fitting too because the original part from 2000 broke while removing the existing hose.

The PVC tube itself is in good shape as its a hard plastic formed line---the replaceable ends are okay but that entire assembly will be replaced with a new part from Ford. It was just $29 which included a new PCV too. Its so nice looking I hate to install it. :)

I tend to use MAF cleaner---not sure if that's snake oil but your point about leaving a film is good. I've not tested brake cleaner for leaving that same film so can't say if that'd work or not. In fact I'll test both products on a clear piece of glass to see if either leave a film when dried.

Poking around inside this particular engine bay most every other hose looks fine and in good shape. Plugs will be changed, the throttle body cleaned in place so if the DTC's come back I'll know there's more work to be done.