vapor canister question
#1
11-05-2011, 03:53 PM
vapor canister question
Trying to figure out if my evap canister is bad. Unless I'm mistaken you should be able to blow through the canister, or are there check valves inside it?
It's been getting harder and harder to get gas in it, at this point I'm lucky to get a tenth gallon in before the gas pump shuts off. And now I'm getting P0466 code.
I tried blowing through the evap vent valve line with all other lines off and couldn't, canister seems clogged. I can blow through the line from the tank but it is hard to do and I can hear the gas bubbling in the tank, gas cap was off at the time.
Shouldn't I be able to blow through any of the ports through the canister??
It's been getting harder and harder to get gas in it, at this point I'm lucky to get a tenth gallon in before the gas pump shuts off. And now I'm getting P0466 code.
I tried blowing through the evap vent valve line with all other lines off and couldn't, canister seems clogged. I can blow through the line from the tank but it is hard to do and I can hear the gas bubbling in the tank, gas cap was off at the time.
Shouldn't I be able to blow through any of the ports through the canister??
#2
11-06-2011, 08:56 AM
I just went through the same issue a few months back with my 02'. It is not your vapor canister. If you have the 4-door model, it is the little box (cant figure on the name atm) mounted on the bed floor, right above the spare tire. If you follow the line from the mystery box to the vapor canister, and unhook it while fueling, you should be able to fuel up...no problem!
Replacing the box thingy was the easiest repair ever on that truck! It took all of 5 minutes, including dropping and raising the spare tire! And yes, on that specific part, you should be able to blow through it. If you cant, the internals are bad, not allowing the gas tank to properly vent, preventing you from filling up.
I will post if I remember the parts name...I just kinda ran into the Chevy dealer one day, went EHHHHHHH!, pointed to the part, and he knew what it was! LOL!
But yeah, it threw the Emissions code for me as well, for years...and it wasnt until my nursing scrubs were covered in fuel after a 30 minute fuel up that I investigated the issue...
GOOD LUCK!
Replacing the box thingy was the easiest repair ever on that truck! It took all of 5 minutes, including dropping and raising the spare tire! And yes, on that specific part, you should be able to blow through it. If you cant, the internals are bad, not allowing the gas tank to properly vent, preventing you from filling up.
I will post if I remember the parts name...I just kinda ran into the Chevy dealer one day, went EHHHHHHH!, pointed to the part, and he knew what it was! LOL!
But yeah, it threw the Emissions code for me as well, for years...and it wasnt until my nursing scrubs were covered in fuel after a 30 minute fuel up that I investigated the issue...
GOOD LUCK!
#3
11-06-2011, 08:39 PM
How did you know what part to get in order to replace this box above the spare tire? If not, does anyone know the name of it? I get some occasional trouble with the pump shutting off before the tank is anywhere near full.
Thank you.
Thank you.
#4
11-07-2011, 08:48 AM
Evap. Vent Valve Again, drop your spare tire, and look at the part. # should be on there! It takes all of 2-3 minutes, depending on the condition of your spare tire system. You are going to have to access the part anyhoo, to see if that is the culprit. (it is, but just to be sure). Blow into the connection, if you dont mind the subtle taste of fuel, and see if you are able to pass any air through the vent. If no, then its a bad part! Symptoms of a bad Evap. Vent Valve include, but are not limited to: Not being able to put gas in your tank, and the idiot light displaying P0446 for a trouble code.
My vent had a different connection than the OEM part that the chevy dealer gave me at first, so be careful when ordering. I would say just bite the bullet and pay the extra $10 at the dealer, and be done with it. For finicky parts like this, I don't trust online vendors. Too much hassle, and too much climbing under the car, in the dead of winter, after working a 12 hour shift
#6
11-08-2011, 07:28 AM
IDK which lines have check valves on the Charcoal Canister?! In theory, the fuel vapors should travel in a one-way fashion. To the vent for disposal or purge for recycling. The vent is the only one connecting to the charcoal canister for storage though, right? I think the purge is a direct link from the tank to the motor, but I could be wrong (it happens alot). For you though, after my doctors appt, I will venture out to the ~~lazy man~~ and test theorys. I have been bitten by curiosity! (and I know my charcoal canister is kosher 
)
The P0466 code is for the vent valve, or the purge valve (near the intake?!), either for faulty parts, or electrical faults to the parts. The fact that you are having issues pumping gas lead me to think mechanical failure of the vent valve (as in my case). The purge valve, to my understanding, allows you to recycle the vapors while you drive.
But in the meantime, if I cant get under my truck for any reason (im crippled ATM), do some trial and error. Unhook hoses until you can fill your truck without an issue. I would say check your fuel inlet pipe (filler neck) for its condition, but the ball inside the tube being clogged wouldn't throw a p0466.
And ANYBODY PLEASE step in and correct me if im wrong, but I would assume that the charcoal canister would have its own DTC # on the idiot light in the dash? Doesn't mean that the idiot light is always right. Stranger things have happened.
PCM's do have hissy fits! I guess you could flood out the charcoal canister with gas if you overfill your truck, but you would smell a large odor of gas...and idk if we can clean our charcoal filters at all?
)The P0466 code is for the vent valve, or the purge valve (near the intake?!), either for faulty parts, or electrical faults to the parts. The fact that you are having issues pumping gas lead me to think mechanical failure of the vent valve (as in my case). The purge valve, to my understanding, allows you to recycle the vapors while you drive.
But in the meantime, if I cant get under my truck for any reason (im crippled ATM), do some trial and error. Unhook hoses until you can fill your truck without an issue. I would say check your fuel inlet pipe (filler neck) for its condition, but the ball inside the tube being clogged wouldn't throw a p0466.
And ANYBODY PLEASE step in and correct me if im wrong, but I would assume that the charcoal canister would have its own DTC # on the idiot light in the dash? Doesn't mean that the idiot light is always right. Stranger things have happened.
PCM's do have hissy fits! I guess you could flood out the charcoal canister with gas if you overfill your truck, but you would smell a large odor of gas...and idk if we can clean our charcoal filters at all?
#7
11-08-2011, 08:37 AM
Update
Got ahold of a compressor and blew the lines out. Both big lines blew through one through the gas tank and the other through the vent valve. The small line to the vent on the manifold vent I believe did not, supposed to be closed perhaps. And all three ports on the canister blew through.
Was able to get in four gallons in at a time, much better than a tenth. And no ses light for 80 miles.
Hopefully 100psi didn't blow any check valves
Will try again in a week or so, and see if I can fill it in one pass again.
Got ahold of a compressor and blew the lines out. Both big lines blew through one through the gas tank and the other through the vent valve. The small line to the vent on the manifold vent I believe did not, supposed to be closed perhaps. And all three ports on the canister blew through.
Was able to get in four gallons in at a time, much better than a tenth. And no ses light for 80 miles.
Hopefully 100psi didn't blow any check valves
Will try again in a week or so, and see if I can fill it in one pass again.
#8
11-08-2011, 11:42 AM
Update
Got ahold of a compressor and blew the lines out. Both big lines blew through one through the gas tank and the other through the vent valve. The small line to the vent on the manifold vent I believe did not, supposed to be closed perhaps. And all three ports on the canister blew through.
Was able to get in four gallons in at a time, much better than a tenth. And no ses light for 80 miles.
Hopefully 100psi didn't blow any check valves
Will try again in a week or so, and see if I can fill it in one pass again.
Got ahold of a compressor and blew the lines out. Both big lines blew through one through the gas tank and the other through the vent valve. The small line to the vent on the manifold vent I believe did not, supposed to be closed perhaps. And all three ports on the canister blew through.
Was able to get in four gallons in at a time, much better than a tenth. And no ses light for 80 miles.
Hopefully 100psi didn't blow any check valves
Will try again in a week or so, and see if I can fill it in one pass again.
#10
12-04-2011, 08:33 AM
P0446 code keeps coming back
I've been throwing parts at a P0446 code on my 2001 Blazer ZR2 for a couple of months. Changed Gas cap, Vent Valve, Purge Valve and Vent Solenoid. I removed and blew out the Charcoal Canister and blew out all the lines attached to all the parts I replaced. The code just keep coming back a day after I clear it. I'm out of ideas. Can anyone help?