Thanks for your answer. Unfortunately I don't have an oscilloscope. I've already tested the pressure sensor in terms of voltage and I get those voltages you mentioned. But testing the pressure regulator is harder, especially because it's hard to reach. Is there any other way to test the pressure regulator, without an oscilloscope? I have a multimeter and a diagnostic tool Icarsoft LRII , thats it. No graphs unfortunately. At most I can connect the multimeter to the regulator, but then...The issue occurs only under load (rarely if I just rev the engine stationary). So how can I test the regulator while driving?:D
The only two things left before blaming the HP pump are the pressure regulator and the throttle sensor. The engine knock/limp and rattle happens not only when I accelerate but also when I release the pedal (sometimes abruptly) and never happens on idle. Also the pedal live readings are very random and don't always show a value based on input. Same goes for the regulator. Sometimes it goes to 4. Sometimes just to 2, under relatively same load. At idle is 0.71. (Is it ampers or volts for pressure regulator current btw?)
Of course I cant exclude the pressure sensor itself.
But basically with pressure sensor disconnected: I understand why the P code/MIL doesnt come up....because the sensor generates it. What I don't understand is why the engine doesn't rattle or knock under load when it's unplugged. So far it seems the sensor generates that knock. It's either by sending mixed signals to regulator...orrr the regulator can't cope. Any other option?
I still believe this is a very valuable clue. The fact that car doesn't choke if it doesn't know the value of the pressure means something is working at least. Can I know 100% something is not broken (HP Pump) just because car works without high pressure sensor?
Also I see the high fuel pressure values oscillate alot. Even at idle....the pressure is never stable...they go up and down. 25-28k Kpa. And under load, it's all over the place. But maybe that's not relevant.
I will try to disconnect the regulator itself and check the O rings as I've heard they go bad sometimes. Can I determine if it's faulty just by looking at it? I suspect the O rings will look normal. Obviously if they are broken I will see, however I doubt car would start if that's the case. If they look normal, I'll just put it back :))