Vanagon CV Engine Fluctuation in Idle/ Stall when Acceleration

[Jannik333]

Hey guys!
I've recently bought a 80' Vanagon with a CV Engine, 2000ccm and L-jettronic here in Germany and did a complete build up with new cylinders, pistons and overhauled heads.
Right now I'm having 3 major problems at once.
When I start the engine cold, I have a fluctation in Idle, which continues even if the engine is warm.
Also when I try to accelerate the RPM the engine stalls, probably because of unmetered air?
When I shut off the engine and its in warm condition, it won't start but just blowing black smoke out of the exhaust while cranking. For me that means the mixture is way too rich, but why?

All standard things are checked up:
Compression OK, Ignition is set and sparks are present, fuel is flowing right to the engine, all grounding connections are new and good, temperature switch is working properly, temp switch II resistance measurement was good as well. Cold start valve is closing to the right time. Fuel pressure regulator is brand new and original Bosch. All vacuum hoses are new and leak-free!


Hope you can help me figure out the problem soon,
Thanks in advance and greetings from Germany!

Jannik

[Jannik333]

Little update: I fixed the stall and Fluctuation Problem, now it's just the black smoke.
What I've did now was a new fuel filter, checked ground cables again, installed a new fuel return hose and some clamps to ensure there is no unmetered air in the engine.
Now I have black smoke again, engine is running but very poor and no power, although I have compression on every cylinder.
Someone thinks it can be the fuel injectors or the ECU?