Overfill check valve?

took my truck in for a smoke test for my pesky p0440 CEL. And they told me that I need to replace my overfill check valve? (pretty sure thats what its called) they said smoke was "pouring" out of that area... has anyone else had a similar problem to this? thanks for any info in advance!

 

I think they are talking about check valve in evap. Did you check your gas fill cap for bad gasket. Not sure but might be related to vps on firewall. Hopefully someone with more knowledge will chime in. Not sure of your configuration but the check valve has check balls that might be stuck. Think you can shoot low pressure air into tank to check operation.

 

(copy, pasted)
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Trouble Code: P0440


EVAP Control System Large Leak (0.080") Detected

Possible Causes:



Charcoal canister is clogged, loaded with fuel or with moisture
Fuel filler cap missing, loose (not tightened) or the wrong part
Fuel tank over-fill check valve cracked or damaged
Fuel tank seal leaking, fuel tank cracked or damaged/leaking
Fuel vapor hoses/tubes blocked or restricted, or fuel vapor control valve tube or fuel vapor vent valve assembly blocked
Vacuum hose or tubing cracked, damaged or disconnected
Vapor Pressure sensor incorrectly instAlled
PCM has failed

 

The valve they are referring to is the roll-over or over-fill valve. It allows purging but prevents fuel from spilling out in the event of an upset. It is pretty easy to change, though you do need to lower the fuel tank.

Easiest way, if you don't have access to a lift, is to place a jack (with a block of wood) under the fuel tank, remove the tank straps (2 straps held in by pins), then slowly lower the tank with the jack. Be sure not to cause strain on any fuel lines or electrical connections. Once the tank is low enough to reach above and feel the valve, you should be good to go to work. There is a metal cover that has 3 bolts that covers the valve. Once the cover is removed, disconnect the evap lines and hose clamps (I think there are 2) with pliers. Once the lines are removed, you simply/lightly pry on the valve to remove it, given it is popped in and held by a rubber seal.

Once removed, installation is just as easy. Be sure to clean the surface of the tank before installing the new one, and also prime the gasket on the new valve with some fuel or light grease to get it to pop back in easier.

As mentioned above, definitely check your fuel cap & gasket as that is a common failure and cause for CEL.

 

For the above posters I have gotten a new gas cap and a whole new Evap can ($$)

 

Can it be reached by removing the bed? I'd rather do it that way if able. I hate working in tight places..

 

Yes, it can definitely be accessed that way. I know some techs would actually prefer that method, but I always would just use the lift so bottom access was my preferred method.

 

just what i wanted to hear! looks like my weekend is planned out haha thanks for the information man I really appreciate it. anything else i should change while im under there? ive already done it once to replace the evap can. and i would like this to be my last time for a while

 

You should be good to go! I can't think of any other "hand-in-hand" parts that go with the valve, other than the fuel cap (which you already got). Have fun!

 

The tops of those tanks can be pretty scrungy. Not a fun job trying to be super careful and not contaminate shit from almost out of sight, but still get it all done once and right. C'mon fuel pump,,keep doing your thang.

Permatex Permashield is your fuel proofer for immersed or 1/2 immersed paper/cork/fiber gasket stuff. Haven't tried it on anything else but it works good with those.

 

Yeah those hinge pins get pretty seized up sometimes.taking the bed off would be my choice for sure. Is that part called a fuel cut off valve? Just curious so op can find lt easy.

 

Roll over valve/cut off valve

Funny they didn't put a fuel pump cut off on that roll over as well. The valve will close but the line pressure will still be up.



Edit: It's listed as a cut off valve.

 

Cool, just for my own knowledge. Thanks
Sometimes I don't know where I come up with this shit! lol
Thanks mod, lol

 

Same P0440 code here on the ladies 2002. Shop said its the overfill valve that requires lowering the fuel tank.

One shop quoted $400 total, another said $600... Sounds like an easy job once you actually get to the damn valve.. Any suggestions?

 

Good luck with this one. I replaced the EGR valve, a couple of vsv valves, filler kneck, gas cap, a few hoses and the damn thing whows up every now and then. The only thing left is to chech everything around the canister to see if all the valves open and close when they need to.

 

Well. The shop said they did a smoke test and it was only the overfill.. so who knows.

Plus she tops off her tank every fill, past the click off.. I told her to stop doing that.

 

Had to do it on my Sienna. Plastic just got old and cracked. Nothing else to do under there unless you want to put a fuel pump on.

 

",,,,only to find out it was a single wire getting wet". That's how it would go with me. Blessed with a behaved 1st gen.

 

May I ask which wire was that?

 

I have yet to find it. It hasn't presented itself just yet.