Back on 11/30, bowedup2003 posted this:
The screw I'm reffering to is on the backside of the injector pump, just above the cone where all the injector lines connect to the pump. Mine has an allen head screw with a set nut, my buddies 91 had a small headed bolt with a set nut. Depending on which way you turn it adjusts where in the rpm range the fuel comes in at (as close as I can tell).
I adjusted mine out 3/4 of a turn, it took away some of the torque at idle (had to give her alittle gas to take off w/clutch), but it made the truck accelerate through the gears like a 350 chevy. It was a very noticeable difference. I ran it this way for about two weeks and was averaging about 14mpg. I pull a trailer alot so I kinda missed the torque at idle (take off w/o giving it gas). So I turned the screw the 3/4 turn back to stock, then 1/2 a turn more in to see what happens. It didn't give my truck any more/less power, but it put it down lower in the powerband. For example, I can take off from a dead stop with my 24' gooseneck in tow loaded with our 60 hp tractor w/o having to give it any gas. It also makes for pulling loads much better, I can hold speed going up hills better now. But to make a long story short, it helped my fuel mileage because I have the 5 speed, I can make all my shifts early w/o any lugging, I normally hit OD at about 45mph. I am now averaging 18-20, depending on where I get fuel, running empty.
Just try playing with it, if you don't like how it runs you can always set it back.
Bowedup
Flyzlo, I've tried this on my 85 6.9. I cranked the screw OUT 1/4 turn. Same performance (for the way I drive), a LOT less smoke during acceleration. My mpg may have increased slightly, but it's kinda hard to tell. Before the adjustment, I was getting around 16.5. Now, it looks like I'm averaging just over 17. For that small an increment, it could be the weather, or just the way I'm filling the truck. We'll see. What I know for sure is, there's a lot less smoke back there, and the truck still drives and pulls the same. Now, how this is gonna work with your turbo motor, I don't know. I would suggest quarter turn increments, and you'll want to turn the screw IN. I'll also pass on what the pump guys that build my pumps told me:
"Don't go more than one turn in either direction. At that point, you're starting to affect other internal adjustments."
. 
OkieG
