Golf 3 1Z Fuel Injector Pump

Today, I cleaned the metering device on a machine with a 1-inch diameter. I should mention that it was also having trouble starting up before.
I then adjusted the settings to be the same as for the ones before it. The MWB 1/3 reading was 0.72V. Before I disassembled it, it was reading 1.36V.
I have set the injection amount to 4 mg/H.

The problem is that it doesn't start without giving it gas, just like before, except that before it was running unevenly. But even when I give it gas, it doesn't start properly; it starts, the RPM drops, and then it goes up again.

I've tried several settings, but the engine only starts if I adjust the mixture screw all the way towards the high-pressure side, at which point it idles.
Approximately 1200 RPM. I also tried adjusting the control voltage on the main control board to 1/3.
Setting it to 0.4 volts doesn't help either, I thought, because then he would just adjust the control slider further to increase the boost.

Furthermore, I increased the initial fuel quantity to the maximum using VCDS, but there was no change, just like when I disconnected the temperature sensor.
In the MWB 5, the injection amount during startup is between 18 and 22 mg/H.
Should the default throttle setting not be set to full load at startup, similar to how it works with mechanical injection pumps using a starting spring?
Is it now the fuel injection pump that's causing the problem, or could it also be the control unit (ECU)?

I'm going back to the workshop now to continue troubleshooting (unfortunately, there's no internet access there).