Could mixture be too rich because of bad injection valve? Options

[velum]

Hi!

I am at lost with my '73 914-4 2.0L FI system... (IMG:style_emoticons/default/wacko.gif) I changed the MPS and calibrated the new one based on the old one (because it was from a 1.7L engine. The old one leaked a bit too much), I changed the wire harness, and I changed injection valve seals, but my engine is not running properly... it sounds irregular a bit like a 2 stoke engine... maybe my engine is running only on 3 cylinders... But my four spark plugs are completely black, so I conclude that the mixture is too rich. I was gonna check my injection valve, but then I started wondering whether a bad injection valve could cause the 4 spark plugs to be black... I don't think so, but I am asking. I played with my MPS inner adjustment screw, and I could get the engine to run a bit better (ie to sound less like it is gonna stall), but then I measured the number of Henrys the coil is giving me, and it way off what I assumed it should be.

My main question here is whether the injection valves could be at fault. And I would like to know if you have any suggestion about what to test next.

Cheers!

JF