Hello, have there a Scirocco 2.0tsi CAWB , came with non upgradable HP pump, so we manage to get new hitachi one from later model and fit VIS upgrade internals. Fitted onto engine with new vacuum pump housing. But now at idle is there almost 200bar of pressure and high pitch noise. No mater of regulator on the pump connected or reversed polarity.
Ecu has only modified the VHDP and RQUAHDPK to better match the VIS piston.
Did someone met this problem?
I faced to this problem than I made CCZB engine from CAWA. If you will read VW SSP from Bosch and Hitachi HPFP you will see that they have different control signal logic. When one gives plus another one gives neutral (ground).
Also CCZB ecu have another internals (it has wide band lambda control controller instead narrow band one in CAWA/CAWB/CCTA/CCTB ecu). Also CCZB engine has another exhaust camshaft with another lobe lift profile and you need to change it too for proper work of CCZB HPFP.
You can read it here with google translate
https://www.drive2.ru/l/527973115225965414/