Have I got a strange problem for you to solve ----

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I have a very strange problem with out 2001 Chevy Impala.

About a month ago the check engine light came an and I stopped at an Advance Auto Parts and borrowed their code reader. Code P0446 came up. The fellow at the counter said that the code is for the evap. vent solenoid. It is a part that is not easily accessed so I had a local independent shop replace it. The check engine light stayed out for a couple of days and it came back on. The same code came up, P0446. I've been pretty busy, but I stopped in the local independent shop again and he said he would have to smoke test the evaporation system. He said when I bring it to him to have the tank low in-case he had to drop the tank. A week ago I needed gas and only put 8 gallons in it which brought it up to 3/4 of a tank, because I knew that I would be driving enough to run it low before bringing it to the independent shop next week. I drove it about 150 miles and it was showing below 1/4, and the low fuel warning light came on just as I was driving it to the shop for the smoke test.

The independent shop smoke tested it last night and fixes a bad hose under the hood.

I got it back today, the gauge was reading below 1/4, and I immediately took it to a gas station to fill it up because I did not want to take any chance of running out of gas. I pumped 1.15 gallons of gas into it and the nozzle shut off. I squeezed the gas filling handle and the gasoline over-flowed from the tank.

For some reason with what I know is less than 1/4 tank of gas, the car will not accept gas at the fill neck. What a strange problem. I took it back to the independent mechanic and told him that I can't put gas in it because it is over-flowing when I do, and that it has less than 1/4 tank of gas in it. He said that all the work he did to it was under the hood. That he connected the smoke test system under the hood, and that the bad hose was under the hood.

What could be wrong? It does not make any sense. I never heard of a filler neck not accepting gas, and I know the gas gauge is correct because I drove it enough for the last week for it to have used up the 8 gallons I put in it last week that only filled it up to 3/4, and I know that with where the gauge was reading last week if I normally would of filled it up it would have taken between 12 to 13.5 gallons when I only put 8 gallons in it.

How can a gas tank not except gas when there is less than 1/4 of a tank of gas in it?
 
Bad evap vent solenoid again? Maybe the original was fine and the replacement is no good?
 
Does the filler tube have an anti-siphon feature built into it? It may have been jammed somehow during diagnostics. Shove a hose down and see if you can jiggle it loose. Just a wild guess.
 
The evap system allows the air in the tank to escape via the charcoal canister. This makes room for the gas to enter the tank. Something is messed up. You need a mechanic that understands how the evap system works.
There are many youtube videos dealing with this problem.
 
I do have a locking gas cap.

I drove it practically every day for the last month since the evap. solenoid was replaced and filled it about once every 5 to 7 days.
 
Originally Posted By: WobblyElvis
The evap system allows the air in the tank to escape via the charcoal canister. This makes room for the gas to enter the tank. Something is messed up. You need a mechanic that understands how the evap system works.
There are many youtube videos dealing with this problem.


+1 That is my thought.
 
Originally Posted By: StevieC
Originally Posted By: WobblyElvis
The evap system allows the air in the tank to escape via the charcoal canister. This makes room for the gas to enter the tank. Something is messed up. You need a mechanic that understands how the evap system works.
There are many youtube videos dealing with this problem.


+1 That is my thought.

Yes, sounds like the EVAP is not letting the tank vent.
 
Bum new part tank not venting as you fill it. Bad diagnosis as usual, codes should only be an indicator of the area that needs inspecting not throw a part at it.
 
Needs a charcoal canister or the valves attached to it if it is like a Toyota. See if you can find a junk yard one. I dug pretty deep into the evap system on a 99 camry. The solenoid they replaced wasn't the problem on mine either. There should be a vent valve also. On mine one valve went bad and let junk into the other making it stick. The The purge valve doesn't do anything when filling. You need to do some testing. The mechanic fixed the leak and now it is sealed like it is supposed to be and showing the real problem.
 
Originally Posted By: JimPghPA
It is only now after the leaking hose was fixed that it will not accept gas.


Yeah, probably because it was venting out that hose and now can't.
 
As mentioned, the tank is not venting. Kind of hard to put gas in a tank that's pressurized with air.

That mechanic should've smoke tested the car on the first trip to the shop. He's a hack.
 
Originally Posted By: Trav
Bum new part tank not venting as you fill it. Bad diagnosis as usual, codes should only be an indicator of the area that needs inspecting not throw a part at it.


Too late to edit. I should have said possible bum new part. The original should have been checked for proper operation before replacement and the new one checked before installation.
 
The problem is now solved.

I left the car with the independent mechanic after I found out that it would not except gas.

It turns out that one of his guys had pinched off one of the hoses when he did the smoke test, and he had forgot to remove the clamp.
 
Originally Posted By: Trav
I should have said possible bum new part. The original should have been checked for proper operation before replacement and the new one checked before installation.


+1....Especially if using aftermarket junk replacements!
 
Originally Posted By: JimPghPA
The problem is now solved.

I left the car with the independent mechanic after I found out that it would not except gas.

It turns out that one of his guys had pinched off one of the hoses when he did the smoke test, and he had forgot to remove the clamp.


Makes sense. If it can't vent, that's exactly what happens.
 
No kidding. I have never seen so much junk on the market, some of it will old once good brand names.
Some of the reman failure rates are beyond horrific more than 50% for some stuff.
 
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I can't believe you guys....
.
chasing Evap system parts when the tank won't fill?!?!?!!?

ALL AUTO FUEL FILL TUBES are independently vented
713ImAZ%2BSfL._SX355_.jpg


some have a "tube inside a tube" for venting

hqdefault.jpg
 
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