If you're getting white smoke on start up, have you checked you air filter?
Like everyone says, the 12HT always puffs smoke on start up. It's how they get the direct injection motor to start so fast, by dumping a heap of fuel in there and away it goes.
If you are still getting black smoke when you stab the pedal from idle, or take off from the lights, then your OFF boost fuel setting is too high.
This is a similar setup to the main fuel screw you have already been playing with.
It is on the back of the aneroid where the pressure line comes into the governor setup at the back of the pump. I think it is a 10mm, same as the front, but uses a flat blade screwdriver to adjust the fuel screw. OUT is LESS fuel = less black smoke. If your pickup from idle to when the turbo picks up is sluggish, then screw this IN a little bit at a time.
This is a much finer adjustment than the front screw where you can go quarter turn each time. The back screw makes a difference at one eighth turn and then test. You're adjusting screws that control a rack, or a rod. Move it left for less fuel, move it right for more fuel. Simple.
Black smoke is not just unsocialable, like others have said, it is highly likely to have been creating FAR too much EGT. Fit an EGT gauge to do these adjustments properly, or find an air fuel ratio probe to stick up the exhaust pipe and get the settings right.
You can increase the air supply, i.e. boost pressure, to burn up excess black smoke. A standard CT 26 can run safely at 15-18psi. Too much boost will cause the compressor wheel to break. This is bad, very bad..... Before it breaks, it will also lose efficiency as the blades cannot maintain grip on the air and it just creates more heat. Many people run them happily at just shy of 15psi, which coincidentally is the pressure the orange light turns on on the dash - those green and orange lights. The green one comes on at 2psi, the orange is an over boost light and comes on at 15psi. To avoid panic, setting your boost pressure to just less than 15psi seems a sensible balance.
A GTurbo will allow you to remove the main fuel screw completely as they are designed to maintain efficient operation at 22 -25 psi without engine harm. The capacity of the injection pump to deliver more fuel is what will limit your power output at this stage, not the turbo. Niffa sent you a link to my website. People seem to find it helpful.
But you're not (yet) chasing performance improvements are you. Your smile will come from no black smoke at the moment. My smile comes from no black smoke either, but I'm just 400 yards/metres ahead of you with four wheel rooster tails in the sand
Injector problems will result in hard starting, smoking at idle and less power. If you know the PO fiddled with the fuel screw, then the simplest and obvious thing, without overcomplicating matters, is to adjust it back again.
Spudman
