[QUOTE= As for black smoke, your fuel pump may have been turned up, and the AFC housing may have been adjusted. The afc housing is on top of the fuel pump, there is a alen head screw with a 12 or 13mm jamb nut on it. Loosen the jamb nut, and back the screw all the way out. I would bet you'll find that its burried all the way in and not sticking up through the nut at all. After that, I would buy a boost gauge to see what the turbo is doing when you getting the black smoke, if boost is staying consistant, how much your running etc... It should be no more than a haze at wide open throttle at full boost if the fueling hasn't been adjusted. Stock boost is around 8 to 10 psi. If your getting that much boost and still have smoke, then you either need to turn the boost up, or back the fueling off by turning the main fuel screw out. Take a look in the performance section, there is a write up on pump adjustments, if your trying to get less smoke and closer to stock, just do the opposite of what the write up suggests!
Hope this is helpful.
Jason[/QUOTE]
If there is black smoke before the turbo spools up, this can be reduced by raising the Allen screw as mentioned as it controls the amount of fuel before the diaphragm is moved. If however the smoke occurs on acceleration, one of the ways this can be controlled is by rotating the pin that is attached to the diaphragm underneath that top cover to a position with a shallower taper. The pin is attached to the diaphragm so by rotating the diaphragm one rotates the pin.
I do not believe you can reduce the amount of smoke produced during acceleration by raising the allen screw on the top...unless the turbo is not working...because as soon as the diaphragm is deflected by the boost pressure, this screw touches nothing.
Much more effective in reducing smoke during acceleration with boost pressure is to rotate the diaphragm. I would suggest rotating it anti clockwise 30 degrees at a time to see how it reacts, after marking the diaphragm position before you start.
Basic bottom line expressed slightly differently is that the black smoke is a product of too much fuel for the amount of intake air present. The excess smoke is just fuel being wasted.
To make the smoke go away either the amount of air needs to be increased or the amount of fuel decreased. Having components in dubious condition will complicate and confuse the tuning process however so all disclaimers apply ;-)
Steve
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