Changed entire evap system, but can't blow out line from engine bay

[Bama704]

I have an 05 Tahoe, and had the engine light on, P0455.

So I changed all things that went with the evap system. Charcoal vapor canister, vapor canister vent solenoid, & vapor canister purge valve.

I can not fully blow out the line going from the tank to the purge valve. With the lines fully open (disconnected on both ends) I blew compressed air from the tank side to the engine bay side and vice versa, however I can still hear the charcoal pellets in the line. Any tips on how to get them all out?

 

[TollKeeper]

If you are positive that the lines are fully disconnected, and no valves, or electrical connectors, are present in the line, I have seen people using water, then once cleared, compressed air to dry the line out.

Its likely not charcoal pellets, but dirt/mud/rocks.

Could also remove the line completely, lots of work, and hang it vertical, while blowing air thru it.

 

[OR VietVet]

I gotta ask, why did you replace all those components and not replace the lines. I did all that on my 05 and the two lines were $19.99 and $107.79 at RA.

 

[Joseph Garcia]

I don't know what the diameter of that hose is, but would it be possible to insert an electrical wire, say a 16 gauge insulated wire, into the hose and feed it through, as far as it will go, and 'push' the obstruction out?

 

[TollKeeper]

.. Or a coat hanger

 

[iamdub]

I have an 05 Tahoe, and had the engine light on, P0455.

So I changed all things that went with the evap system. Charcoal vapor canister, vapor canister vent solenoid, & vapor canister purge valve.

I can not fully blow out the line going from the tank to the purge valve. With the lines fully open (disconnected on both ends) I blew compressed air from the tank side to the engine bay side and vice versa, however I can still hear the charcoal pellets in the line. Any tips on how to get them all out?

When I did this on my '08, I messed up by trying to shotgun the pellets out of the line with 150+psi. That just made them compact together in the bends of the lines, forming clogs. There are loose pellets between these clogs and that's what you hear rattling. I had to beat, shake and flex the lines near the bends to work the compacted pellets loose, kinda like those glow sticks you bend to crack and make them glow. I then used light puffs of air to gently move them through and out of the lines. When I had the tank dropped, I removed the hard lines from that and whipped them all around while beating them against the concrete to knock the pellets loose. Afterward, I could go full throttle with my blow gun into the line.

I never thought about trying to dissolve them with water. I'd be interested to see if they'll dissolve. Can you get some that you've already gotten out, like from the EVAP canister, and soak them in a cup or something?

 

[Bama704]

Sometimes it's easy to make things difficult.
I just ordered a new line. Will be here on Friday and will change it out. Thanks.

 

[OR VietVet]

Did you order both or just the one?

 

[Fless]

Another thing to try is using stiff weed whacker line to push through. If I were to need to do this, I would start from the canister end, since that's probably where most of the charcoal is, and push it back up the line a little to see if I could loosen it up. Then the method that @iamdub mentioned, with short puffs of low pressure air from the engine end while vibrating the line.

 

[blueinkd]

Glad I didn't have this issue when I did mine. May I asked what you are using to blow these things out. A proper blow gun with the correct blow tip at the nozzle will ensure maximum air delivery. Your regular metal tipped nozzle won't deliver the same air volume/pressure. Considering the length of the lines I had to use a different tip on my blow gun.