Filler Neck/EVAP Leak

J

joserw

New Member

Aug 12, 2009

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Aug 21, 2009

#1

• Aug 21, 2009

• #1

I am getting a code for a P455 LARGE EVAP LEAK. I had the car smoked and it was pouring out of the gas cap. I replaced the gas cap with a Motorcraft cap and had it pressure tested and it passed. My mechanic is telling me I need a new filler neck? I have never heard of this. It isn't cracked as far as I can see and it isn't leaking at the grommet either? Has anyone ever had this problem before?

 

nyuk98gt

15 Year Member

Oct 10, 2000

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Chesterfield, MO

Aug 21, 2009

#2

• Aug 21, 2009

• #2

joserw:

If the system passed a pressure test with the new cap, I suggest drviing it around for a few days to see if the problem (code) reappears. It is not uncommon to have the grommet in the neck fail but when it does it usually causes a dribble of gasoline so you really know it is in bad shape. (No, I have not had this problem but I have read a bunch of threads on various boards about it. Just relaying the general info.)

HTH,

Chris

 

J

joserw

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Aug 12, 2009

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Aug 22, 2009

#3

• Aug 22, 2009

• #3

Thanks, I have gotten this code every time I clear the ECU. I had a different mechanic look at it and he said he has never seen this before... there is like a black "bladder" almost in the trunk where the filler neck exits the vehicle. He thinks there is something wrong in there because smoke is coming out of the drain hose when only liquid gasoline should be coming out of there when car is over filled. If you peel away your trunk lining you'll see this "bladder" I am talking about. I guess I am going to have to deal with Ford?

 

nyuk98gt

15 Year Member

Oct 10, 2000

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Chesterfield, MO

Aug 22, 2009

#4

• Aug 22, 2009

• #4

joserw:

The Ford shop manual (I don't have access to my book) has a diagram of the gas tank and connections. It doesn't show the internals but you need to have a Ford tech take a look and offer his opnion. You can always go in for a diagnosis and then replace the parts yourself (if you don't mind working on the fuel system). I am somewhat of a chicken about the fuel tank so I would leave it to the pros. (Spouse would be a bit upset if I set the garange and house on fire while executing another "car project", lol).

Sorry that I can't offer much more info to assist.

Chris

 

J

joserw

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Aug 12, 2009

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Aug 24, 2009

#5

• Aug 24, 2009

• #5

Bear with me here: the EVAP system is a closed system. When we smoked the system, smoke was coming out of the overfill tube under the car (the tube that drains gasoline when the tank is over filled). Now, if I am correct, that tube should not be venting smoke (back to the closed system) so perhaps there is so sort of valve that is broken? Am I right in the mechanics of this?

 

nyuk98gt

15 Year Member

Oct 10, 2000

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Chesterfield, MO

Aug 25, 2009

#6

• Aug 25, 2009

• #6

joserw:

Yes, Sir, there should not be smoke coming out of the overflow tube. That seems to be the leak/opening to the atmosphere that is causing the evap system to generate a fault code.

I don't have access to my shop manual (on the road) but the Ford parts counter guy (or your technician) could pull up a schematic of the tank system. I just do not recall how that tube is connected into the tank.

Chris

 

J

joserw

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Aug 12, 2009

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Aug 25, 2009

#7

• Aug 25, 2009

• #7

Unfortunatley, I think the filler neck is all one piece so the entire thing will have to be replaced... it's a $200 part from Ford. Unless there is something inside of the filler neck assembly that I am missing?

 

J

joserw

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Aug 12, 2009

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Sep 4, 2009

#8

• Sep 4, 2009

• #8

Just to let everyone know, I took the car into Ford and according to them, only Ford can smoke their vehicles because there is a solenoid that needs to be closed in order to close the EVAP system. Only ford has the computer software to manually shut this solenoid. Turns out it was the filler neck grommet and my vapor managment valve (which I never heard of) was faulty. Car has since passed inspection. Hope this helps somebody in the future.

 

nyuk98gt

15 Year Member

Oct 10, 2000

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Chesterfield, MO

Sep 4, 2009

#9

• Sep 4, 2009

• #9

joserw:

Thanks for posting the update. For certain, it will help others (who use the 'search' feature).

Glad to hear your car is running well again.

Chris

 

ToplessStang

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Mar 7, 2004

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Montreal, Canada

Sep 7, 2009

#10

• Sep 7, 2009

• #10

Ya I've seen quite a few filler necks cause evap codes.

Most are 2000-2003 Taurus. I replaced the one on my Windstar because it was all rusted up and causing a leak.

As for closing the CV Solenoid, your right we can close it with software but it can also be done buy clamping the vent hose with needle nose vise grips because if it is not blocked off there is no doubt you will see smoke at the gas cap area during the smoke test.