2003 Boxster-S fuel Smell
 

Hello,

I am chasing a fuel smell on 2003-S with 55K miles, the smell is more pronounced when car is parked in the garage. Based on my reading; I took out battery and I don't see any visible crack on the fuel sending unit including both the nipples (pressure line and return line).

However, I found that there is some type of seal/Glue/Wax (see picture and thing 4 o'clock, yellow rubbery looking). I am not sure if PO had it same problem and had it repaired or this is how it comes from factory.

When I try to smell it around, I feel like that smell is coming from front right and left tire ( both) areas.

I would really appreciate any help.

Jay

trying to attach picture
 

First:
When you fill up with gas do you stop putting gas in when the handle clicks off?
Or do you try to squeeze in a few more ounces of fuel?

Second:
there is a purge valve behind the right front wheel liner it may be faulty.
There are also other hoses associated with the EVAP system.
If you click on the Boxster racing forum and view the thread about removing the charcoal canister there are pictures of what I am talking about.
Could be an issue with something there.

Third:
Do you ever have starting issues after a fill up or when the engine is warm?

If you look in the PET page 58 it shows a sealing ring around the fuel pump pn 321-919-133 I suspect this is rubber & yours is cracked/dried out which is causing the smell. This would be what I would look at. Other thing it could be is the fuel cap leaking out but if that was happening you would most likely throw a code for it.

This looks like it could be a generic VW part also from searching.

I stop filling when gas station pump aaiti shut, never try to get little more.

No starting trouble after filling the gas.

I looked at vent valve behind right wheel, blew little air through the pipes there.

Changed gas cap with OEM gas cap.

I think smoke test will tell the right reason rather than randomly throwing part at it.

Has anyone seen that wax/glue if you ever look at fuel sending unit how it was j stalled from the factory

It's pretty easy to see if that seal is the issue. The top black union just unscrews.

smoke test wouldn't hurt either but might not show a leak there unless it's under pressure which is what the tank will be and why you are smelling the gas.

If you have a Durametric I think you can go to activations and pressure test the EVAP system. I am not positive though. I think it will show percent of leak down or pressure loss.
You could also pull vacuum on the EVAP system to see if the charcoal canister holds vacuum.
Mini Vac would do it.

I actually have gas pudding on top of the fuel sending unit!

Jay, Slider, I had a similar fuel leak on my wife's S60 fuel tank cover that looks very similar to the one posted by Slider...

On the S60, the leak was caused by a crack on the hard plastic cover (at the base of the electric connector) and that round piece, is part of the fuel sending unit.

I believe that on the Boxter this round piece supports both, fuel float assy., And the fuel pump assy.,
however, on your picture it seems that the previous owner used sealant as this is not the way it came from the factory as someone already mentioned, there is a large O-ring that seals between the round plastic (yellowish color) cover to the fuel tank.

First you remove (unscrew) the black ring in order to be able to remove the round plastic cover, and then you will find the thick large O-ring.. If the leak comes from a worn O-ring, buy a new one and I would suggest to lubricate it with silicon grease before you install it.

Also, you may want to do this job with an almost empty fuel tank, don't ask me how I learn that.. :p

Note: I believe that the O-ring sits between the round plastic (yellowish) cover and the black locking ring on top. The the round plastic cover sits flush on top of the fuel tank with the O-ring on top (at least on the Volvo..