AFTER DEP LAX; AN A321 EXPERIENCES A FUEL IMBALANCE WARNING ON THE ECAM SYS. CREW DIVERTS FOR EMER LNDG AT ZZZ.

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DURING CLB AFTER DEPARTING LAX; ECAM-INDICATING 'FUEL AUTO-FEEDING FAULT' ANNUNCIATED. FOLLOWED BY 'FUEL IMBALANCE' FROM MALFUNCTION FUEL FEED SYS. DIVERTED TO NEAREST SUITABLE FIELD AFTER DECLARING INFLT EMER. UNEVENTFUL OVERWT LNDG ACCOMPLISHED. CAUSE UNKNOWN AT THIS TIME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FO SAID THAT THE CTL VALVE INVOLVED IN THE METERING OF THE FUEL WAS OF A FAULTY MATERIAL. WHEN THE MATERIAL DETERIORATES THE VALVE DOES NOT ASSUME THE CORRECT POS FOR A BALANCED FUEL FEED. IN THIS CASE; ALL OF THE FUEL FOR BOTH ENGS WAS COMING FROM THE L MAIN TANK. IN THIS CASE THE CREW WENT TO MANUAL XFEED. THE XFEED DID NOT WORK; SO THE CREW TURNED OFF THE L BOOST PUMPS; LEAVING THE R ONES ON. THAT DID NOT CHANGE THE FEED FROM THE L MAIN TANK. FLT DIVERTED TO ZZZ. ON FINAL APCH AT 500 FT AGL THE CREW RECEIVED A 'R WING TANK VENTING OVERBOARD' WARNING. ONCE ON THE RWY THEY TURNED OFF ALL BOOST PUMPS WITH THE CFR VEHICLES WATCHING THE ACFT. ON LNDG THEY HAD 4000 LBS IN THE L TANK AND 15000 LBS IN THE R TANK WITH APPROX 26000 LBS IN THE CTR TANK. THE ACR SAFETY DEPT SAID THAT THERE WAS NO DANGER OF THE ENGS FAILING FROM FUEL STARVATION WHEN THE L TANK RAN DRY AS THE OTHER TANKS WOULD HAVE TAKEN OVER. AIRBUS KNOWS OF THIS PROB AND ANY DAY NOW IS COMING OUT WITH TEMPORARY PROC FOR AN INFLT FIX WHILE LOOKING FOR A NEW MANUFACTURER FOR THE VALVE.