P0440, smoke test, now what?

[theirare]

I drive a 2001 SR5 with a nagging P0440 code. I'm being forced to fix it because I can't pass an emissions inspection this year without it. I have tried many of the common fixes and was told by my trusted local shop that I needed to have a smoke test done on it. As they don't have a smoke machine, I had to take it elsewhere.

The new shop ran the test and found a small leak near the gas cap, so they put in a new gas cap and it was still leaking. I didn't see them run the test but the next thing they suggested was replacing part #77291-35060. Pictured below:

I ordered that part, but there is another plastic part that I'd like to try and replace as well. Circled in green here:

It seems like this gray plastic piece and the black rubber piece that I already ordered create some sort of seal with the gas cap and fuel filler neck. Maybe I don't know what I'm talking about, but does anyone know the part number for this gray piece? I was unable to locate one online or find anyone else who has had a similar problem.

Although I didn't see the test being performed, the mechanic at the new shop said that the fuel filler neck looked fine. After feeling around there, I'm inclined to agree with him. It all seems very solid with zero rust.

Thanks in advance and any help is greatly appreciated. I'm also willing to try any other novel suggestions you guys might have to fix this problem.

 

[BlackCat914]

I drive a 2001 SR5 with a nagging P0440 code. I'm being forced to fix it because I can't pass an emissions inspection this year without it. I have tried many of the common fixes and was told by my trusted local shop that I needed to have a smoke test done on it. As they don't have a smoke machine, I had to take it elsewhere.

The new shop ran the test and found a small leak near the gas cap, so they put in a new gas cap and it was still leaking. I didn't see them run the test but the next thing they suggested was replacing part #77291-35060. Pictured below:

I ordered that part, but there is another plastic part that I'd like to try and replace as well. Circled in green here:

It seems like this gray plastic piece and the black rubber piece that I already ordered create some sort of seal with the gas cap and fuel filler neck. Maybe I don't know what I'm talking about, but does anyone know the part number for this gray piece? I was unable to locate one online or find anyone else who has had a similar problem.

Although I didn't see the test being performed, the mechanic at the new shop said that the fuel filler neck looked fine. After feeling around there, I'm inclined to agree with him. It all seems very solid with zero rust.

Thanks in advance and any help is greatly appreciated. I'm also willing to try any other novel suggestions you guys might have to fix this problem.

Try a light coating of silicone grease around the new gas cap seal and see if it stops leaking.

 

[theirare]

Thanks for the advice, BlackCat. I ran into a problem though.

I went to Autozone to pick up some silicone grease and all I could find was stuff that had the word "sealant" on it. Not wanting to permanently glue my gas cap in, I passed.

Amazon has this stuff. Is this what you meant?

 

[jgue467]

Probably, but it should not cost $22+! We're talking about silicone lube, s/b $3-4 at walmart or where ever they have auto parts in your area. Might just try some petroleum jelly instead. Luck!

 

[allwheeldrive]

Sil-glyde is a good lube if that's what you want. Have they tested the vsv's up front, like the purge or charcoal canister switching valve. Make sure all of those hoses are connected and not cut or dry rotted. Otherwise, the seal for the fuel pump sending unit could also cause an evap leak.

 

[theirare]

Thanks, jgue467. I was thinking something like petroleum jelly might work. I'm going to give that a try and will update here.

Allwheeldrive, all of that looks good. In fact, I replaced the charcoal canister within the last year due to this code, obviously with no luck. The mechanic told me the smoke test revealed a leak near the gas cap area, but I didn't see exactly where. Where is the seal for the fuel pump sending unit?

 

[allwheeldrive]

It would be on top of the gas tank. But if you have never had any work done in that area, I wouldn't bother. The chances of it being bad for no reason is extremely slim. I had the fuel pump out of mine a few months back, didn't change the gasket cause I forgot to order a new one. Still don't have any codes, so I know it's fine. Take a picture of the filler neck sealing surface. Is the gas cap oem?