| Answer: | **DISCLAIMER**
YOU are responsible for any consequences of injector pump tampering or failure!
The injection pressure of the VE injector pump is not as high as the P7100 pump used on 94-98 models. For additional power with the VE, larger injectors can be installed. Some engines do not respond to pump adjustments. In cases like where the pump is maxxed out with no improvement, increasing the injector size will flow additional fuel. Non intercooled trucks built before January 1, 1991 have larger injectors(9mm) and will get more boost with pump tweaking alone than the later model intercooled trucks with the 7mm injectors. I reccomend that you get a Boost and Pyro gauge before attempting any of these adjustments. Not only will these give you a baseline to start at, it will also tell you if you have set your pump too high.
There are 4 main adjustments on the VE pump:
Low manifold pressure (boost) fuel delivery adjustment,
This adjustment is fairly simple and will help considerably around town at low engine speeds and low boost conditions.
There is a small cap in the center of the 'fuel-control device' atop the pump (the 'appendage' that is plumbed to the intake manifold and restricts the amount of fuel injected until the manifold pressure is above atmospheric). This cap can be readily removed with two small screwdrivers and a gentle rocking motion. Beneath the cap is a torx T-25 screw and a lock nut that holds it. The locknut is 13 mm and has a 'break-away torque' of around 100 in-lbs. Turn the T-25 screw 2 turns clockwise and tighten the locknut to 125 in-lbs. For additional fuel (and smoke) the screw may be turned farther (CW). Back it off (CCW) to reduce smoke. NOTE: this will increase the exhaust temperature by about 75 degrees F on long grades. Clean the plug with CRC Brake cleaner and seal it with LocTite pipe thread sealant with teflon. Externally, it will appear stock.
Full load fuel delivery rate adjustment.
The main adjustment is found under the AFC diaphragm that is held on with a 4-screw cover. MARK THE POSITION OF THE DIAPHRAGM, then remove the diaphragm -- there is a stamped tick mark on it, so use a magic marker or scribe to note the position of the diaphragm vs. housing. Remove the diaphragm and shaft, and note the shaft is both tapered and on an eccentric. Usually, rotating the shaft 120 degrees clockwise will cause the wear to go to the richest (smallest diameter, effectively) part of the shaft. You may want to start at 90 degrees and then go farther if that does not produce the power you want. The farther you go, the higher and faster EGT will climb. The fuel stop part rubs up and down along this shaft, and note the way to install the shaft that allows maximum travel of the fuel stop part that hits this shaft and is perpendicular to it.
Just pay attention and mark stuff so you can put it back the way it was, and you should be able to figure it out just fine. After adjusting the diaphragm eccentric, the low boost fuel rate may need to be adjusted slightly to reduce low speed smoke.
AFC Star Wheel Adjustment
Under the AFC diaphraghm and spring is a star wheel adjustment which sets the spring tension on the fuel load delivery rate diaphragm. If your star wheel (under the AFC spring) is set too high, the delivery rate pin won't move downward as it should with increasing boost levels. Turning the star wheel up (counterclockwise) increases the spring pressure, and slows the delivery rate. I'd suggest turning the star wheel down (clockwise) in 1/4 turn increments until you smoke, then back off (counterclockwise) till smoke is gone to your satisfaction, or smoke on under power, a black haze, not a black soot cloud. The retaining lock spring doesn't have to be removed, the star wheel will rotate with a small screwdriver gently placed and pried between the wheel and it. Note the location of the wheel, mark it, and count any turns for reference. Remember: Star wheel down=less spring resistance=increased fuel delivery rate.
Full Power Adjustment
Unless your AFC or Diapraghm is way out of its proper setting. This is all you should have to adjust.
On the rear of the pump, partially concealed by the fuel lines, and under a plastic cap is an other adjustment screw. Remove the plastic cap, remove the metal collar tack-welded to the screw, loosen the jam-nut, and turn the power adjustment screw clockwise about 1 to 2 turns. After turning the Full Power Adjustment, you may need to re-adjust the Smoke Adjustment Screw to reduce low speed smoke, and the idle screw or throttle linkage to correct the idle speed.
If your smoke is only at full throttle load - back off the full load screw.
If your smoke is at low end thru pull-up - Back off the smoke adjust screw on the top of the diaphragm housing. If you have dramatically adjusted the "star wheel" (the cogged adjusting wheel under the diaphragm) it can have the same effect, as even very slight boost will cause it to move to "full fuel", instead of waiting for the turbo to spool up a bit. Adjust the star wheel back a bit to reduce the smoke level.
If smoke is heavy at immediate start-up - fine adjust the smoke setscrew.
By: Monty
Click on "Download Attachment" below, to view the illustration of the VE pump and the location of the adjustable settings. Other photos of the VE pump can be found here http://www.dieseltruckresource.com/yabbse/gallery/thumbnails.php?album=161[/b]
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