My 1989 non-Hess V12 XJS Convertible developed a leaking fuel tank that has now been professionally repaired. A very loud whoosh when opening the fuel filler cap after shutdown, undoubtedly led to eventual fatigue failure of the tank. Unfortunately the whoosh concern continues so, I temporarily vented the filler cap to prevent a repeat tank failure. Now, to find and correct the cause of the problem without further excessive repair costs. The old related Recall had been done and the lines from the tank to the canister appear undamaged. It would seem likely that a purge or Rochester valve may not be functioning properly...perhaps one under the LHS wheel arch at the canister? Would appreciate any next-best-step guidance from someone experienced with this concern. (Hate to give-in by having local Jag dealer attempt repairs.)

Submitted by jcpim@cogeco.ca on Thu, 12/05/2013 - 22:42

Hey Sean:
Pardon my not advising you sooner but, the used purge valve that I purchased from you and installed, worked perfectly! No more whoosh from pressure/vacuum build-up in the fuel tank.
Many thanks to both you and Steve for your interest and assistance.
Joe

Submitted by SC98-63972 on Thu, 07/18/2013 - 00:02

Joe,
Try doing a search for ACDelco 214-552 Vapor Canister Purge Valve. Appears to be a good replacement. Valve was in just about every GM product from 1990-2001. One listing even had a picture of a Rochester valve. I couldn't find specifications on line but at least one Jag owner tried it and it worked. I would expect any auto parts store to have one or able to get it in a day.

Gives me another easter egg to look for in the junk yard. When I find one I'll report back with pressure responses.

Email sent if you want a bonafide Rochester Valve.

Submitted by jcpim@cogeco.ca on Wed, 07/17/2013 - 20:30

Steve: Thanks for the info on how to properly test the valve. I hesitate to try to do that at this time. From all that I have read on the fuel vapor whooshing issue, I suspect that the Rochester Valve (CBC7714) is indeed the culprit. I would like to obtain a working one (or equivalent NA vehicle part) for trial, before getting into the canister area. However, I have been unable to find a source....any suggestions? I realize that this is akin to throwing-parts-at-the-problem but, neither do I want to have my car down for a long time while I try to source this hard-to-find part.
Now Sean; it sounds like you may have an extra working Rochester valve on hand. Should you care to profitably part with same, please email me at jcpimatcogeco.ca. Thanks.
Joe

Submitted by SC98-63972 on Mon, 07/15/2013 - 18:30

Great timing on this post, thanks Steven. Sorting extras and found 2 valves, both check good. Also was changing steering gators and checked the one installed. All good, thanks again.
Sean

Submitted by stevejag@sbcgl… on Sun, 07/14/2013 - 23:54

You can test the Rochester Valve if you have a hand vacuum pump that has a vacuum gauge.

Take the valve off and connect the vacuum pump to the small vacuum nipple. Apply 15" vacuum and see how long it takes to trail off to zero.

If the vacuum takes five seconds or more to trail off to zero, the valve is considered good.
Less than two seconds is a failed Rochester Valve.
If between two and five seconds, cover the two large nipples with your fingers and retest to 15" vacuum. If the time for the vacuum to trail off increases, it's a failed Rochester Valve.

Evap systems are convoluted and complicated; lots of valves & hoses. You may well be better off to let a dealer help you out. Just try and find someone who's been around a while, and has a bit of detective in his nature.

Good luck!