"How to" for 1st Gen Cummins...... - PerformanceTrucks.net Forums

"How to" for 1st Gen Cummins......

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Old 07-05-2005, 07:26 PM   #1
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Default "How to" for 1st Gen Cummins......

Here is some info for the other first gen guys out there with the 89'-93' Cummins.

1.How to turn up the VE pump....

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.
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Old 07-05-2005, 07:29 PM   #2
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Default Installing 3200rpm spring.

2.How to install a 3200rpm spring.....
Installation of Governor Spring: Bosch #1-464-650-366
in the Bosch VE Injection pump.

There is some dissasembly of the VE pump required to complete this modification. Keeping the internals of the VE pump free from dirt/dust/debris is extremely important.
The following instructions may not be 100% complete since most of us, including me, are not pump tech's.
This mod can be done with the pump on the truck.

1) Mark current pump timing locations on pump and gear cover, then loosen pump and let drop towards the drivers fender.
2) Disconnect the throttle linkage at the throttle arm/lever on the pump.
3) Remove the TPS, AFC cover and diaphram/cone from inside.
4) Mark/note position of all the screws such as idle, full fuel, high idle etc.
5) Remove the idle screw, full fuel screw, this is needed to access the 4 main allen screws that hold the pump top on. You may get away with leaving one or two in.
6) The allen screws on the back (engine side) of the pump top can be hard to reach but you MUST have a good grip on them even if you need to tap/hammer the allen key down into the allen heads.
7) Remove the 4 allen screws.
The allen screw on the fender/front side of the pump serves more than one purpose. It holds the throttle shaft in place, the spring(s) underneath such as the "breakover spring" and the head of this allen screw is were the TPS shaft rides, on the auto tranny equiped trucks. Once the screw is removed look down into the hole... you'll see a tiny slender black stem with a slot in it. This slot position is very important since it is the "index mark" for the throttle lever.
The allen screw noted comes off in the following order; allen screw, throttle lever arm, breakover spring, washer,
(at this point you should see a flat plate with tick marks like a clock on it. Note the position of the slender black stem in relation to the tick marks. In most cases the slot in the stem will align with the second from bottom and second from top tick marks... kinda like 4:00 and 10:00 so to speak.)
Try to leave the lower spring, cup, mount in place. Once you progress to removing the pump top, you will loose some fuel from inside the pump so have a drip pan below to catch the dribbles.
9) VERY CAREFULLY lift the pump top upward about 1 1/2" while looking at the back (firewall end)engine corner inside. You should see a slotted piece of metal with a what looks like a tophat w/tiny spring IN the slot (careful this puppy can jump out on you and an extra pair of hands makes this part easier). On the inside END of the tophat is the one end of the gov. spring. Using forceps or tiny needle nose pliers, carefully unhook the spring from the end of the tophat.
10) Turn pump top over and remove the other end of the gov. spring from under the pump top.
11) Attach one end of the new gov spring to the underside of the pump top, and very carefully attach the other end to the same spot on the tophat. (don't worry, you can put the spring in the wrong place, just be slow and careful.)
12) Lower the pump top back down in place, shifting it slightly to seat it in place.
13) Check your index marks as you begin the reverse process of assembly. (Most mistakes are done here so take your time)
14) Tighten the allen screws to "just right ft/lbs torque" (sorry I don't have torque specs for this but you should be able to tighten by feel.)
15) Reverse the proccess of dissasembly and tighten as you go.
16) Once all the screws, AFC, housing,TPS, etc are in place, return pump to timing marks you made on the pump body/gear case and tighten it down. Here you'll have to get as close as possible to original screw positions for your idle, high idle, full fuel etc.
When you've gone over everything 3 or 4 times to make sure you've done everything, you're ready to try a start up and idle.
**NOTE** Remove the air inlet tube from the turbo inlet and move to the side. Have an emergency board or whatever to cover the turbo inlet in case of runaway condition. BTW, using your hand could qualify you for the handicap award and being named 3 finger Dave or Stumpy.
A second set of hands helps here too, while you activate the manual shutdown lever (in case of runaway) your help can cover the front of the turbo to starve the engine of air)

17) Start the truck..... hope it keeps running. It may need a couple tries due to fuel loss from removing the pump top.
It should pretty much start right up.. it may stumble and clear up OR, you'll have to re-prime using the lift pump handle or plugging the filler spout with a rag and shooting compressed air in with a nozzle/air hose to force fuel thru to the pump. (If you do it this way, make sure someone is watching the low pressure bleed screw on the side of the block and tighten it when you get a steady stream of fuel from it.)

At this point it should be running. Try 'burping' the throttle a few times. Make sure that the engine returns to idle promptly as it did before the spring change. If it lingers at higher RPM and slowly drops down, take that as a sign of being close to runaway condition. Back out the full fuel screw 1/4 ~ 1/2 turn, restart and try again. I also recommend running your high idle screw in a fair bit to make sure you can "work up to" you intended high idle setting and avoid RPM flare.
You should be able to reset your low idle, full fuel, etc without too much trouble.
Take a test drive at this point and watch your EGT's, idle, etc.
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Old 07-06-2005, 01:08 AM   #3
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gezss i wish i had a 12V
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