Just noticed a major fuel leak resulting in a pool of gas under the car. Upon further investigation the fuel pressure regulator is leaking. I assume I just replace it instead of fooling around with seals or trying to recondition the part? Never thought I would have to worry about a fuel leak with the XK8 as I owned a XJ-S and that was a constant worry on those cars. Is there an easy way to relieve the pressure in the fuel system without the special tool referenced on the JTIS CD?

 

Fuel leaks on the cars are rather rare, but I guess we might see more as they age. Just replace the fuel pressure regulator.

There is a schrader valve (just like a tire valve) on the fuel rail. Remove the cap and depress the button to relieve the pressure. Have a rag over it so it does not squirt on you.

 

Just replace the Fuel Pressure Regulator and it's hose which is probably dried or cracked. It is an easy 10 minute, one screw fix. The FPR itself is a wear item and will give you starting problems when the diaphram becomes stretched.

Ethanol fuel will hasten the deterioration of all "rubber" fuel system components. If you can use non-ethanol fuel, sometimes called Recreational Gas. Here in WI it is the same price as 10% ethanol.

You don't need a special tool, really.

 

You could relieve the pressure by using a small tool to open the Shrader Valve at the rear of the right fuel rail. Hold a rag near the fitting to absorb the gas.

 

I did find my fuel pressure test gauge with the pressure relief valve and proper size fitting. But if the pressure falls over time and only a small amount will drain onto a cloth when I press the Schrader valve then I guess I will do that. Oddly enough I can’t find a lot of suppliers for the FPR.

 

Here is the part from Gaudin Jaguar...price looks better than some aftermarket sources. Jaguar Parts - Direct JPLV Porsche Parts.com

 

Did not know about FPR, if it's a wear item as mentioned could someone post a pic or diag of it and location? Thanks.

 

The 03 on Fuel System uses a Fuel Pressure SENSOR that sends a signal to the ECM which controls the Fuel Pump Speed. There is no Fuel Return Line.

The SENSOR is connected to the Fuel Rail in the Extreme Lower Right of this Pic:

 

The fuel system is different for the later models. There is indeed a small fuel pressure regulator on mine. I took it out. It still holds vacuum. It is leaking at that area. I also have two wet injectors adjacent to it. Sounds like I am getting way too much full pressure at the rail. Is that a symptom of a bad fuel pressure regulator or a bad full pump? The gas is leaking heavily even with the key in the “2” position without being started.

 

The Pump would not cause that. The Fuel Pressure Regulator would cause it. Of course, a leaking O-Ring or Injector itself could be the problem.

You should get a Fuel Pressure Gage and connect it to the Shrader Valve and check for the Correct Pressure.

 

I wanted to provide some feedback on this issue I had recently. I finally received a new fuel pressure regulator and installed it. Everything is fine and back to normal. Fuel pressure gauge shows it holding about 40 psi steadily with no leaks. I am curious though about how many people may have thought, as I did, that the fuel smell in my car was from the common P0455 Evap Gross Leak. Last year the evap valve was replaced. This year I replaced the gas cap. I just kept resetting the code with my code reader. I just assumed that the reason for my gas smell was this code. Is it a coincidence or can a bad fuel pressure regulator cause the P0455 code because of too much fuel pressure at the rail? Not until I pulled off the engine cover did I notice the fuel leaking at the regulator. Gas evaporates so quickly that unless you are looking for it you may miss it. There was no performance issue with my car or other codes.