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.
On cars Audi, FV with an engine 2.5 TDI V6 installed fuel injection pump (high pressure pump) VP-44.
At one time it was a technological breakthrough in terms of efficiency and environmental friendliness. At its core, this hybrid pump is something between purely mechanical and fully electronic as 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.
And the electrical part is the control unit, located on top of the injection pump and two valves, which the control unit controls the injection pump. It is a metering valve and a valve advance. Control of the metering valve takes place with the use of rather large currents up to 25A through the 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 check the timing valve and the metering valve is a video.
The main causes of failure of the field-effect transistor:
- airing of the fuel system and as a result of the transistor overheating
- shorting between the lead valve wires (the isolation of the lead valve wires just crumbles over time)
- seizure of the injection advance piston inside the injection pump
- interturn closure of the metering valve.
ali.pub/2prz0o - here you can buy an R-L-C tester.