Hello out there!

I have been looking around to see if there are any guides or pictures that show how to replace the charcoal canister behind the drivers side rear wheel. I came up short on YouTube and Chiltons wasn't much help either. I took a peek under there and it does not seem to be too involved but i did not know if there any special tools that need to be used.

Any tips are appreciated.

I was going to tackle this on Sunday but too bad the Cubs let Cleveland win a game so I will have to reserve Sunday night to watch the game!!!

Thanks!

 

its been years since i did one, i too dont think theres anything special just 10mm bolts? biggest issue youre going to run into in the midwest is rusty bolts.

also i believe on some if not all blazers that plastic piece on the outside of the bumper comes off with a few screws to help you get at it easier

 

Good call in removing the rear bumper cap. I appreciate the tip! I'll document this process with pictures.

 

I tackled the job in about 2 hours. I documented the job with photos.

 

if mine ever comes off, it's getting relocated... wish there was an easy way to delete the dang thing...

 

Thanks for posting up the canister removal pics, out of interest were you getting a service light/code coming up ?

 

As much as I take from the forum here, I will try to give back

I did not actually have any lights or codes pop but I have not been unable to fill my fuel tank past 3/4 and the heavy smell of gas fumes when I do fill stink up the truck. I went to inspect the vent valve underneath and managed to inadvertently snap it while trying to remove it from the arm. I had to replace it and still no difference. I then figured I would try to diagnose the purge valve under the hood and when I pulled it, the rubber was worn, torn and it fit pretty lose once I removed the studs. I replaced that with an AC Delco valve that fits much more snug and that still did not fix my issue. Lastly I pulled the hose off the canister and noticed a few drips of fuel come out so I figured I would replace the entire canister and document it. While the canister went in with no problem.................... my problem still persists....

I am not a fan at just throwing parts at problems with out proper diagnosis but it just seemed that these parts were either broke or showed significant visible signs of wear so out they went. I still have to do further investigation as to what the problem is but I have a few more things I am going to check.

Fuel tank pressure sensor...

Kink in the fuel lines...

I also read somewhere in here about a filler neck ball getting lodged...

One good thing resulted, the fuel smell went away when I gas up!!!!

 

As it turns out I just did this on my 2001 Chevy Blazer. They must have changed at some point because mine is the style of the dirty looking one in the pic. I had to send the new one back and get the correct style.

I also was getting the fuel smell anytime I was near the tank. I replaced the valve a few times then replaced them both a once. I also had the EVAP code, large leak I believe it was.

Nice write up, thanks for sharing.

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Curious if you were able to isolate your problem with the pump shutting off? I too dont want to throw a bunch of parts at it for nothing but for 20 -30 bucks for a new purge valve or vent solenoid on a 20 year old car it cant hurt anything. My issue worse, have to fill up slow to get any fuel at all im leaning towards a stuck anti rollover valve "ball" to but dont see any or many breakdowns or talks about it. Considering shoving something into my filler neck to knock it loose. Any help or suggestions from you or the forum would be appreciated.

 

There are some misconception here so I will try to help clarify which may help some of you fix your trucks without the parts cannon. I am not familiar with every model and variation so I will give a generic description for GM that should apply to our trucks.

The purpose of the evap system is to prevent fuel vapors from escaping into the atmosphere and to improve fuel economy. This is accomplished by controlling fuel tank venting, capturing fuel vapors, sending the trapped vapors to the engine to be burned, and to routinely test this system to make sure that it is not leaking.

The gas cap is sealed and a vent tube goes from the gas tank to a charcoal cannister then the CC is vented to the atmosphere through a normally open vent solenoid. Another line goes from the cannister to a normally closed purge solenoid near the engine intake.

The vent solenoid is normally open so that the fuel tank can fill and be drained with pressure relief to the atmosphere. The charcoal cannister captures fuel vapors so that this venting does not release fuel vapors to the delicate outside world. So why would you have trouble filling your gas tank? Because there is no proper venting to the atmosphere. Why can this happen? The normally open vent solenoid valve is faulty and closed. One of the lines is blocked with insect crud or dust. The charcoal cannister is blocked. Some vehicles are equipped with a rollover valve where the vent hose leaves the gas tank on its way to the CC. This check valve is sometimes integrated into the tank pressure sensor. As a side note, there may be an antisiphon valve as part of the filler neck that can swell or otherwise fail and that can prevent filling because the filling process is blocked, not because the tank will not vent to allow room for the fuel. The filler neck is simply no fully open.

The lines to the purge valve and the purge valve have nothing to do with a no fill issue because the solenoid is normally closed. A failure would only help this situation but cause other problems. The purge valve is opened at set intervals to draw the stored fuel vapors from the CC to the engine intake to be burned. Again, the vent solenoid is open as it almost always is.

The routine testing involves closing the vent valve (the only time it is closed) and either pressurizing the system or temporarily opening the purge valve to create a vacuum, then close both valves and see if there is a leak. This test is done with the engine running and uses either engine vacuum or a separate pressure pump. Some vehicles also use the natural change in pressures after the vehicle is off and at rest. This is one reason why the VCM may stay on for a while on some vehicles.

What do the failure codes mean? When the test was conducted, the temporarily sealed system would not hold vacuum/pressure so something is leaking: hose, valve, cannister, tank, gas cap. The leak is usually described as either large or small to aid in the diagnostics.


George