Как переделать перекачивающий насос в подкачивающий. Audi A6C5 2.5TDI V6

Hi, my name is Oleg, I am an amateur mechanic, I always maintain and repair my car on my own, than I share with you. The 2.5 TDI V6 engine is quite technically complex, but the HP-VP-44 high-pressure pump is a general thing, of course it was put on many brands of car, but in essence it is a hybrid pump — something between a purely mechanical and fully electronic like HDI. VP-44 has a lot of weak points; the mechanical part is the wear of the plunger pairs and the wear of the slide (vane) pump, which sucks the fuel out of the tank. But worst of all - this is the control unit, which is located on top of the injection pump. The control unit controls two valves - the dispenser valve and the advance valve. Control takes place with the use of rather large currents up to 20A through a field effect transistor. The transistor is cooled by fuel. If the fuel system becomes airborne - the transistor overheats and fails - the car does not start. How to eliminate airing - replacing the fuel filter and valve on the filter (mandatory), cleaning the mesh in the tank, hermetic fuel hoses and connections. But there is another simple option - it is just to redo the transfer pump in the tank to the boost pump for option 2. At the same time, when the ignition is switched on, the fuel pump will be supplied with fuel at a pressure of about 0.6 atm. But there is one thing - this alteration is valid only for the front-wheel drive. On a full drive, the tank is double, there are needed hoses from the tank from the engines BAU, BDH, since 2003, the same principle of fuel supply began to be done at AUDI plants. Pros: there is no airing (I have been driving for more than a year already); we facilitate the work of the slide pump and increase its resource; no problems with aeration. Minuses: if the pump in the tank fails - the engine stalls; if there is a low level of fuel in the tank and at the same time drive on steep mountains - the pump in the tank can suck in air.