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Turning up the pre 94 Ram diesel injector pump
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02/04/2007 05:23 PM
Turning up the pre 94 Ram diesel injector pump
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http://dodgeram.org/tech/dsl/more_power/Power_ve.htm
DodgeRam.org > Main > Diesel Index > More 12V 1st Generation Power
1st Generation Ram Diesel Power
Increase
1989 through 1993 Models with the Bosch VE injector pump
My disclaimer:
The torque capacity of the Getrag five speed, a well known weak link, will
be exceeded by an increase in the engine output. Additional exhaust smoke
will exceed pollution standards. Also remember, you can't make more
power without adding more fuel.
YOU are responsible for any consequences of injector pump tampering!
Figure 1
All Adjustments can be made without removing the pump from the engine.
Low manifold pressure (boost) fuel delivery
adjustment.
See: Smoke Adjustment Screw in diagram
This adjustment is fairly simple and will help considerably around town at low
engine speeds and low boost conditions.
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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.
This adjustment will TURN UP THE POWER and smoke. (NOTE: this will raise the
EGT very quickly at full throttle):
The main adjustment (effects are similar to swapping the torque plate on the
P7100 pumps) 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.
Clarification of how the full load diaphragm eccentric works - posted to the
TDR forum by old school:
The eccentric tapered pin that's attached to the diaphragm is the FUEL
DELIVERY RATE pin. Now from above, looking down at the pump, almost to the
bottom of the bore that the delivery rate pin came out of, is the bore that the
trigger or action pin rides in. The linear axis or centerline of the action pin is
parallel to the axis of the pump drive shaft, or the engine crank shaft. The
movement of the delivery rate pin (down with increasing boost levels) allows the
action pin (which by internal spring pressure is contacting it) to contact the
increasingly smaller diameter. This allows the action pin to move rearward, which
increases the fuel delivery rate. As a note: according to my books, and Bosch
injection manual, the "stock" or base line for the diaphragm position is 12:00 as
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you look at the pump. In other words, the tick mark is toward the valve cover, for
the normal setting. I have seen this not to be true on at least two trucks, one of
which was on my own. If you look at the underside of the diaphragm, and can see
where the eccentric would push the pin in deepest toward the front of the pump,
that is the LEAST delivery rate setting. Consider that 12:00. I've found that
rotating the diaphragm clockwise from that point to 3:00 is a good place to go.
Depending on the injectors that are in, and your turbo boost, you may want to
turn a little more.
More From the TDR forum
BushWakr provided this
excellent drawing for those who
are confused by the eccentric
configuration.
Shrimpy provided this
description:
Here is something that will set
you straight every time when
dealing with the AFC diaphragm.
When you remove the cap, go
ahead and put a reference mark
on the rubber piece and part of
the metal housing it is sitting in.
Then very CAREFULLY, pull up
on the rubber diaphragm and it
will slide up. Look at how the
shaft that the diaphragm is connected to is tapered towards the bottom. I refer
to it as being cylindrical, but slightly off center. It has a "deep side" and a
"shallow side". You want to position it so that the deep side (the one that will
allow the pin that rides on the shaft, to move the most) to be oriented toward
the front of the engine (radiator). Mine was set just the opposite, it had the
shallow side toward the engine allowing the pin to move the least. Now that
everyone is thoroughly confused grab your tools and get to Work!!!!
This assembly note comes from WestTN: "DON'T OVERTIGHTEN THE BANJO BOLT
ON THE AIR LINE!!!!" This bolt is very thin walled. Take careful notice how loose
the bolt actually is after breaking the paint loose.
While you have the diaphragm removed, here is another modification From
hdm48:
After doing some serious testing and checking I've found a way to improve the
around town power that doesn't require flooring it. Under the diaphragm there is a
nylon stop. It looks like a thick washer. This stops the eccentric from traveling
down too far. I noticed my fuel pin wasn't traveling all the way up the taper so I
wanted to see what would happen if it did. So I shaved .090" off it. WOW!!! part
throttle power went way up. I checked with Northland diesel and they said it
would not effect my max power settings so it should be safe and no, the pin will
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not travel too far. It can't by design. I'm very happy with this little adjustment.
AFC Star Wheel Adjustment
posted to the TDR forum by old school:
Under the AFC diaphragm 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. This diagram of the
location was posted to the TDR forum by joesoot.
Hey Guys!!! What the heck am I turning, I see a lock nut and a stud that looks
like a torx bit, is this what I am supposed to be turning??? This thing I was
turning is under a gray metal cap, I didn't see any star wheel???Is the smoke
screw and star wheel two different things???
Yeah! Your turnin' the wrong screw too! That's what I was doing! You must
remove that whole cap there with the 4 straight head screws. Under this cap,
there is the "starwheel". It looks like a gear. It clicks when you turn it. It adjusts
the tension on that colorful spring under there. Turn that clockwise and always
make sure to mark the original position so you can put it back if needed!
Full Power Adjustment
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.
--
Does anyone have any tips on removing the "welded" on collar on the boost
screw? I was able to turn mine in about 3/4 of a turn before the collar hit the
locknut. Just that small turn made an incredible difference in performance and now
I "NEED MORE "
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From Dave Ellingson <d.ellingson@worldnet.att.net>
The easiest way to remove the collar is to back the whole unit out of the pump,
put it in a vise and remove it (the collar). Be careful not to turn the screw in the
lock nut as you are doing this or you will lose the "known" setting of the pump.
After removing the collar simply reinstall the unit and adjust accordingly.
According to the TST webpage, a few engines can't be turned up with these
adjustments and they must have larger injectors installed to increase engine
power.
Idle Adjustment:
Any tricks to get at the idle adjustment?
R #1: The trick that I use was a hole punch and tapped the locknut a little to
loosen it up. Then a small pair of pliers to turn the screw up or down. This seemed
to work the best for me without pulling everything apart. Good luck, it is
frustrating.
R #2: I took a 10mm box end wrench and bent the box end portion at 90
degrees to the rest of it and put it on the lock nut with the handle coming out
toward the front of the pump. Then clamped a small pair of vise grips on and that
allows enough of a turn on it to loosen and tighten the nut. Adjust idle with a
small screwdriver.
R #3: I took the dremel grinder to the end of the idle screw after I got so
aggravated at trying to fit the dern wrench in there to adjust my idle. Oops! It
worked though, and I have plenty of adjustment if I ever need to turn it back up.
R #4: A "tubing" wrench will work on the nut, but turning the screw is
another matter. You might try a rubber hose slipped over the screw if it isn't too
tight.
R #5: I bought the special Cummins wrench for this job and it is still a pain!
Once I get the locknut loose the screw will loosen itself (reduce idle) with the
engine idling! I use a small jeweler's screw driver to turn the idle UP (engine off to
allow progress).
R#6: Tap the edge of the idle lock nut with a small flat chisel to break it free.
Once the idle is turned down tap the nut back the other direction to lock it back
down.
To loosen and tighten the adjustment locknut
Cornwell Tool wrench P/N 7268 used on a mid 80's ford escort timing belt
adjuster works great.
A chainsaw bar wrench works well too.
Injectors:
Many people with 1993 trucks like the Bosch part # 0432133875 injectors.
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Additional Notes:
Found on the Land Rover Forums - A long discussion about VE pump adjustments
and a link to a Land Rover VE pump adjustment page (in French) with good
illustrations and photos. You can punch the French URL
http://philippe.trinquet.free.fr/ into the Altivista Babelfish translator and view
most of the information in English.
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 and will get more boost with pump tweaking alone than the later model
trucks.
From PowerWagon: Some of you may have noticed a little rubber "boot" on the
upper part of the pump near the diaphragm. If you take that off and remove the
little "nut" under it, you can use a WD40 can with the little red tube to squirt
some lubricant and rust prevention in there. Do it annually. It may save you quite
a bit of money on pump repairs on a rarely-driven truck. Make sure you put the
boot back on and point it downward to keep dirt and moisture out.
From PowerWagon and OldSchool: If you have excessive smoke after making
pump adjustments:
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.
89 to 93 Rams used 18 cm2 and 21 cm2 turbine housings on the turbocharger.
These large housings do not produce enough boost at low RPM if you increase the
fuel significantly. Consider replacing the turbo housing (available from TST) with a
16 cm2 turbine housing (Holset P/N 3521927) to improve boost and keep the EGT
in the safe range. Some have been happier with a 14 cm2 wastgated housing
because it provides more boost at low engine speeds.
The exhaust pipe leading down from the turbocharger is a known bottleneck.
Exhaust improvements will reduce EGT significantly above 2000 RPM, and improve
turbocharger spool-up at low RPM. Several companies offer a free flowing exhaust
system.
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Have fun. Dave
Posted to the Cummins List by Walt K.
I am sending these to the list and in public because I -strongly- doubt there is an
early truck (pre-'94) left that is still under any warranty. I make absolutely no
claims and accept absolutely no responsibility for anything that may happen if an
owner of an older truck decides to make use of this information.
In order to increase the horsepower of the early trucks, one must carefully locate
two adjustments, one is in the smoke-limiter and will be adjusted to allow greater
fuel with low manifold pressure (initially, this is adjusted to minimize black smoke
at low rpm/low manifold pressure conditions... but, we cannot build manifold
pressure without fuel). You must remove the circular seal-plug from the center of
the aneroid device. This reveals the first adjustment. This adjustment will
markedly affect the feel of the truck's launch, making it pull from a stop more
strongly. Adjust this in 1/4-turn increments until you 'like' the feel at launch and
record the adjustment so you can return it to 'normal' in preparation for a smoke
opacity test, if you reside in such a state.
The second adjustment is where the *real* gain comes from... There is a
concealed adjustment on the 'back side' of the pump... essentially behind the fuel
lines. [See the power adjustment screw on fig 1 above] You must uncover the
adjustment screw and turn it 135-degrees clockwise. You may have to reduce idle
speed back to 750 rpm after this adjustment. The 135-degrees will give you of the
order of 230hp...
Remember two things -- this will void any remaining warranty and that I make no
claims beyond assurance I *have* performed these two adjustments on my truck
over 45,000miles ago. In short, if you chose to follow my example, you are on
your own in event of breakage.
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