12mm plunger problem

Hello to everybody Im new in the club, wish everybody good health n luck.
I got a MK4 with 11mm pump from Renault and 0.380 nozzles. Few dayz ago i decided to install 12mm plunger from VW LT 2.8 4cyl. When i put it to the pump with camplate DE015 (from 90hp pump), it cannot make advances. The case pressure valve is set down to 6.8mm (it makes 11bars case presure). Also i have tryed with different springs for the mechanical advance valve. The best I did is 13 degrees for second and it drops to 7-8. The car is with stock fuel pipes from the tank to the filter ( filter is with 2 pipes, in and out, no valve on it). I'll be very thankfull if somebody help me to solve this.

Does the advance go away at high fueling, high rpm/no load, or is it just low all the time?

You may need better fuel supply (if case pressure drops when injecting a lot of fuel) you'll definitely need it if you're planning on using all of the capability of the HP fuel system

there also may be a different initial advance built in to DE015 camplate, I'm only familiar with 110 and 143, meaning you may have to advance the pump at the pulley if you're running out of advance piston travel.

The advance is controlled 100% by the cold start valve, there isn't a built in RPM dependant timing curve like there is on a mechanical governed VE pump. Piston sees case pressure on one side, and fuel inlet pressure on the other. Sometimes with that large of injector you will see no pintle lift sensor activity at idle, so it'll set a base 44% cold start valve, this is normal.

Yes, it goes away at high rpm... Im asking for 18 degrees it does 13 for a second and drops. At idle I have advance, it keeps 7 degrees and 2.8 cold start valve.

Still didn't answer about the engine load but hey...

Slap a lift pump on it. I'm running carter p4600hp