Hello to the comunity,
The only place in the network to find some information about what the rail pressure should be after engine off, was this site - In the article about high pressure sensor testing in common rail diesels.
My car is BMW petrol direct injеction and Im trying to diagnose intermittent long cranking.
I have stable 5 bar low and 150bar high pressure at idle and under load high pressure goes to 200 and low stays at 5, which is within the specs.
After I turn off the engine, the low pressure goes slightly up to 5,4 and the high pressure starts to drop(reverse flow through the HPFP i guess, but is it normal?) For 30 secs it drops from 150 to 100 bar and continues until it equalls the low pressure, then both fall to about 4 bar.
I am going to remove and test my injectors for leaks and spray pattern , but I wonder if it's normal this high pressure drop after engine off.