During my last track event, I noted two concerns, one was it was difficult to fill the tank on some pumps (worked fine on some) and there was a very strong smell of raw gas at the rear of the car. I NEVER overfill and have never overfilled so how likely is it the charcoal canister has failed or is this getting to be a common problem with these cars due to age?

 

Hard to fill is many times a stuck closed cannister close valve or blockage in the vent line, or failed vapor loss cap. But the fuel smell by the right rear tire where it vents would also be stuck open . You can have multiple issue like either the cannister valve or a bad vapor loss cap which is the plastic top of the fuel tank opening. But it takes diagnosis to verify the failure/s

 

 

You should have a check engine light if any of the emission components are malfunctioning. These might have been disabled when the tune was installed.
Many of the emissions testing features within the ECU can be turned off or on as the car is sold in many different international markets. Typically the destination country in the ECU is set to ROW or some country where emission / EVAP standards are not required to be monitored.

 

If ya have even a cheapo OBD2 reader you can check the EMISSIONS STATUS to see if the EVAP stuff is green, red or yellow. Could be a really quick troubleshooting step. It won't definitely pinpoint anything, but it COULD verify an EVAP problem.

 

yes to close the valve, then i use a hydrocarbon sniffer. Or you can smoke test the evap system at that point and check for fuel vapor or smoke escaping. And yes you should have like a p0442 small evap leak in any case

 

I should also mention that a fuel leak most times wont show as a evap leak and you could have a flange leaking on top of the tank and on your car the evap loss valve is a non servicable(iirc) valve on top in the center and would require a new tank if thats the issue. And scratch what i said before i tought you had a older xk. On the 08 you have a charcoal cannister center above the diff and a dtml leak detection pump that you can run a test on sdd to see if you have a tight system or not. You cars fuel tank sufers from cracked fuel tank plastic flanges or leaking gasket but without taking the tank down or using a bore scope youre not going to see it. The xj and xf has a access port under the back seat. The xk has a place to put a 12pack of beer or jacket for a back seat , SO NO ACCESS PORT

 

 

Different stations' pumps dispense fuel at different rates. If the amount of fuel in exceeds the amount of air out through Evap, that will trigger the pump's auto-shutoff.
This exact thing happened quite a lot on my old F250, and more often the longer it went on..... until I replaced the EVAP canister. After replacement everything was fine.

 

 

Well, my wife calls me the other day and says the gas pump keeps shutting off when filling. Today we went to 2 different stations (that I frequently use) and same issue. Got 7 gallons in 50 cents at a time.... No fuel smell, no codes being reported according to the Torque app

guess I'll look into it this weekend

 

Yeah, "Evap Canister".

 

Which, if so (and it seems evident) is pathetic. Although I am the 3rd owner, not sure if the POs overfilled or not, it's still pre-mature IMO, especially considering the location of the EVAP canister. Put it in the engine compartment or accessible via the fender well and who cares if it fails. But in top of the fuel tank? Pathetic.

I have two 16 yr old cars that don't have this issue...

 

Yeah I was just reading the manual on pulling the canister. "Remove the rear differential" - really? There's no other way to access?

 

I never did find a solution to this. SDD scan yielded no codes. Tank fills up fine every where I go for a fill up. The only time this is ever an issue is at the Shell station by the track AFTER every multi-lap session when the car is hot. And yes I still smell gas vapors at the right rear, but only at the track. Other vehicles fill okay at this station as well as many of the other track day participants who also use this Shell station.

 

Any way to push compressed air through there without dropping the rear end and pulling the canister Jeremy? I'm guessing no but the diagrams in the manual are a bit hard to make out. Did you run the test recommended by Brutal or given the infrequency and the service station, not worth the effort?

 

SDD yielded nothing, likely because I would only be able to recreate the scenario at the track. The only way to see anything is to drop the rear end, a lot of effort. Since it ONLY happens on track days, which are only a few times per year AND really the only annoyance is taking 20 minutes to fill the tank (plus my need for things to work as they were designed to).

I used the on track fuel pump once out of needing a fill mid session but it was $150 for one 4 minute fill up vs. $50 at Shell 😮. Another time some one broke down and didn’t want to haul their fuel back so I used their 5 gallon cans and had no issue filling that way. I reckon the solution is to buy a bunch of cans and do manual fills.

 

Sean, yes the canister & associated items are above the differential at least on my 2013 XK. I had to have it replaced shortly after buying my car due a persistent diagnostic code. Apparently, the code had been cleared by the previous owner. The whole rear suspension etc were on the shop floor! Cost about $900.

 

Digging up an old thread, but wanted to share that my 2010 XK has an access point underneath the rear passenger (US) seat
where the flange can be accessed.

 

Good to know - that might work for the 4.2 L