Just had reconditioned diesel fuel pump fitted for audi a6 2.5, now they tell us it keeps cutting out, and that it could be the immobilizer, is this true?

it indicates that there is a fuel shortage problem
check the supply pump for fuel supply to the pump elements
if the fuel supply pump is part of the injector pump , there could be a blockage in the fuel line or air still in the system
of there is a good supply of fuel to the pump then contact the shop that reconditioned the pump
if you just fitted another pump without reconditioning it , then talk to an accredited diesel pump specialist shop

is this car fitted with an immobilizer?
if yes the operators guide tells you ever step here.
the PCM decides to run the pump. not you.
immo happy
spark good
crank engine, do you have full fuel pressure cranking, yes, no.?
if no pressure cranking any scan tool will tell you WHY its cutting fuel.
called DTC errors.

Grant, you need to check if the pump is ok with your model engine, not just the car model number, these cars were fitted with at least four
different engine variants that i am aware of.
i don't think you should attempt to fit it if you don't know at least that much, sometimes the cambelt has to be removed first, thats a whole
different kind of level of experise required.
good luck

First check whether you have fuel. Second check whether fuel comes to the engine,Third check whether you have spark if is a petrol engine or if is diesel is another matter-does the solenoid on the diesel fuel pump work to release fuel goes through,four check whether your car is fitted with immobilizer or the ignition key dropped and lost the immobilizer chip,or the ignition switch does not send signal to spark.

sounds like the immobilizer is kicking in.you may have to go to vw to get it progamed.

FIND THE CAUSE BEFORE YOU JUST REPLACE THE PISTON AND RINGS. MOST LIKELY TOO MUCH HEAT FROM CLOGGED FUEL INJECTOR. COULD HAVE INGESTED SOMETHING THAT DAMAGED THE TOP OF PISTON TO START THE PROBLEM. COULD HAVE OVERHEATED ALL OVER, BUT ONLY #1 WENT FIRST.
I WOULD FIND THE CAUSE BEFORE FIXING WHAT HAPPENED.
TAKE THE INJECTORS TO LOCAL INJECTOR SHOP BEING SURE YOU KEEP #1 SEPERATE AND TELL THEM WHAT HAPPENED.
THE DIESEL FUEL INJECTION REPAIR SHOP CAN USUALL TEST THESE TOO.
GO TO THE SHOP THAT REPAIRS INJECTOR AND PUMPS, NOT THE PLACE THAT WORKS ON BIG RIGS.
HOPE THIS HELPS, ROBERT

have you tried replacing the Fuel filter, your pump wont cut back in if there is pressure at the pump, the filter on my A8 is just under the rear Right hand sill in front of wheel arch, it has a plastic/fibre cover hiding it, otherwise just follow the fuel line from the pump ,otherwise it may be the fuel pump relay heating up and breaking contact, try to have a diagnostic done,my relays are under the passengers feet , if you intend keeping the car get yourself a workshop manual from bentley publishers, its worth gold in the long run , what does the A6 have normal coil ignition or a ignition coil for each plug, if so that may be your answer,a diagnostics check will tell you

HI,HANNAH,I SUSPECT YOU HAVE AN IMMOBILIZER PROBLEM.IF THERE IS A ORANGE LIGHT FLASHING ON THE CLUSTER WITH AKEY IN IT THEN IT IS THE IMMOBILIZER.THE PROBLEM WOULD MORE LIKELY BE THE DATA FROM THE KEY IS NOT GETTING TO THE IMMOBILIZER CONTROL UNIT,USUALLY A BAD CONNECTION AT THE READER COIL ON THE IGNITION.YOU MUST CLOSE THE TERMINALS SLIGHTLY AND INSULATE THE WIRING SEPERATELY.ANDY

HI,COULD BE ONE OF FOUR THINGS,1-PUMPS DO BURN OUT TRY A 12V DIRECT FEED TO TEST 2-FUSE? 3-FUEL PUMP CUT OFF SWITCH ,IF FITTED NEEDS RESETTING .4-FUEL PUMP RELAY GONE (COMMOM) THANKS.