So, I have been trying to track down the source of a raw fuel smell and I believe that I have isolated the purge valve as the culprit. What is the normal state of the purge valve? I would imagine that it is normally closed. I unplugged the connector that supplies voltage to the valve and started the engine. I then verified that the connector was supplying 13VDC as it should. Then when I put the connector back on the valve I could feel no actuation in the valve. Just in case I wasn't able to detect the valve movement over the vibration of the engine running, I turned the engine off, removed the connector again and applied 13VDC directly to the valve and again could detect no valve actuation.

To those of you that are far more experienced with this valve than I, could you please verify if I am on the right track? Thanks in advance.

 

The purge valve is operated by the ECU. It has 2 vapor lines that and one vacuum line. It is a normal open valve and the ecu closes. You should be able to remove the 2 vapor lines and with the electrical connector unplugged you can apply air to the vacuum line and you should have flow. If not the valve is stuck closed and the purge valve will need to be replaced.

 

I am trying to avoid removing those hoses unless I am certain that the valve is bad because those clamps look like they will be difficult to remove and replace. Shouldn't I be able to feel or hear the valve solenoid when it actuates? If the valve is normally open, is the ECU sending voltage when it wishes to close the valve? It seemed like the connector was getting constant voltage when the engine was running. Last, is there a way to open this valve up? It seems like there is a removable cap on the upwards facing cylinder portion of it. This cap on my valve is loose to where you can rotate it slightly both clockwise and counterclockwise but it does not want to come off.

 

Maybe this extract from the AJ26/AJ27 engine management course sheds light on the issue.
Unlike avern1 stated above, the manual indicates that the purge valve is normally closed and opens ECM controlled. In my view, this makes perfectly sense as only a closed valve will prevent fuel vapors from escaping from the evaporative canisters.
@avern1: Don't be mad at me

 

xjr2014_de, Thanks for the additional info. It is typical of Jaguar. The tech manual and real life are sometimes at odds with each other.

 

I replaced (swapped a known-good) a purge valve in a 2001 XJ8 the other day for fuel smell in engine compartment and P0172/P0175 (RICH Bank 1&2).

I am still test driving the car but the purge valve is Normally Closed on both the line to the canisters and the part-load breather pipe.

The small vacuum line operates the valve when electrically opened.

bob

 

My 99 XJR had a distinct fuel odor that I tracked to the passenger side one calm night. When I got under the cat the smell was coming from the purge valve which was closing but must have been slightly open. I got a new one from SNG and no more smells. It was a pretty easy job but there are a few parts involved that would be tough if they were given a chance to oxidize...

 

Yea, I didn't think that the purge valve was normally open as it just would not make sense. I really appreciate the clarification and I have a new purge valve on the way. I will let you all know how it works out.