So my 97 xk8 has always had a pressurization issue in that when you removed the fuel cap you would need to do it very slowly as there was obviously a pressure difference (air would run into the tank) and if you removed it too quick it would splash fuel all over the side of the car. Never had a check engine light or code for it until today. Got a p0440 code which is for a large leak. Checked the gas cap and no pressure there. I'm guessing my lack of attention to the first issue lead to the second so where do I start. Any ideas?

 

There is a fuel tank pressure control valve that maybe stuck, see pic

 

But doesn't that just power up to run a test to see if it holds pressure? If it was stuck why would I always seem to maintain too a tank that doesn't seem to let air into it? Not real good at the EVAP syst

 

There isn't much more in the system that could cause a blockage. Do you have trouble filling the tank also? Lucky for you, it is a lot simpler to get at, than a convertible. I imagine with the warmer weather you are building some serious pressure. Since you already have a code, you could take a hose off of, or remove the valve completely for a bit, and see if the problem goes away. If it does, the valve is probably the problem. Good Luck....Mike

 

With regards to the fuel tank not taking any fuel inside and pressure developing in the tank while engine is running.

We have already replaced the fuel canister but emission control faults are still there.

One of the pressure relief valve was damaged inside and we removed the broken pieces.

It hasn’t cured the issues and still pressurizing.

Please let us know can we get new pressure relief valve or maybe a used rebuilt working replacement tank

Can I get the pressure relief valve inside

Jaguar XK8 2002

VIN: SAJDA42C42NA30576

Thank You

John….

 

Its a convertible in Dubai