I have a thread in another forum, but I thought I would see if anyone here has some insights into my issue. I have a 2010 TDI Sportwagen in the NSC without DTC codes. I replaced the engine wiring harness and crank sensor due to the car going into limp mode with a crank sensor error code. The car has 378k on it so my mechanic consultant recommended I change both. After completing the installation, I needed an extra power wire to get power to the fuel metering and fuel pressure valves. Once that was complete, I changed the fuel filter, ran the fuel system activation protocol in VCDS and cleared all codes. I then started the car and it ran for 15-20sec then died as if its fuel supply was cut and has not started since. I have double and triple checked the wiring installation as well as all the things I removed to get the wiring installed. No blown fuses, no pinched wires, I get fuel to the rail however the fuel pressure is only reading 8bar (actual) on VCDS and calling for 400bar (specified). Low pressure side of the fuel supply is fine, checked both by listening and collecting fuel out of the hoses. I have checked the fuel filter and the fuel metering valve for metal fragments and there are none present. Given all of the above, my thoughts are the following (not in any order): 1) a failed HPFP that has not catastrophically failed and sent metal through the system, 2) ECU failing, 3) fuel pressure sensor and/or pressure regulator valve failure, 4) something else I'm missing. ECU is reading engine RPMs and other data appropriately as far as I can tell. I would like to measure actual rail pressure manually incase the sensor has failed, but do not have the high pressure measuring tool. Has anyone seen this behavior before or have suggestions on the next steps to get this car running?