I have a fully rebuilt 1.6 TD, (except for the pump being non turbo). I have the fuel screw turned up a bit and it drives great at 50-90 mph, but at lower speeds it is over fueling and causing it to chug as the turbo is pulling but fuel is perhaps not regulated correctly.
The only thing I am concerned about is damaging anything. I can regulate it for the most part with my foot on the pedal. Out of curiosity will the turbo pump stop the problem or is it simply because I have the pump turned up?
How is your timing? When our pump timing was off, we'd get some lugging at low speeds.