| In 1994, Ford employed the "HEUI" fuel
injection system for their Powerstroke engines. The HEUI, (short for
Hydraulic Electronic Unit Injection), system used hydraulics to actuate
the fuel injectors. Powerstroke engines come with two oil pumps, a "low"
oil pressure, and a "high" oil pressure pump. The high pressure oil pump (HPOP)
serves to provide high motor oil pressure (up to 3500 psi) to the
injectors. In the search for higher horsepower, it was discovered that the
HPOP couldn't keep up in instances when a chip or tuner demanded high oil
pressure. When the pump lagged, pressure to the injectors lagged, and a
complete fuel shot was not provided. This was happening on my truck. On
the last dyno run I had, when my HPOP reached 1400 psi, it began to
falter, leading to low HP and TQ numbers. I got in touch with Gary Stecher,
of Stecher Performance.
Gary, along with his associates Jerry and Wes, developed the
Stealth Pump. This was the original inline
pump. There have been some knock-offs from this, but rest assured this is
the real thing. The Stealth Pump is dual hpop, inline design system, made
to lay in the valley of the engine. The installation takes a bit more to
accomplish than other dual hpop systems, but by laying in the valley, the
engine compartment retains its "stock" appearance, thus the "Stealth"
name. This writeup will detail the installation, first impressions, and
lastly, proven dyno increases due to the pump alone. |
|
Installation is pretty straight forward.
First, disconnect the battery cables. This is a safety measure to
prevent you from shorting out something you really shouldn't. Plus, you
are going to be removing the fuel bowl, exposing diesel fuel to the air,
and any spark could create some "tense" moments. Then you need to remove
the CAC tubes, fuel filter bowl, the cross over "Y" pipes and anything
else that looks like its in the way.
 One thing to remember when you
take off the "Y" intake pipe...put a rag down in the hole. This prevents
something from falling into the intake while you are working on the
truck. Once you have gained some room, its now time to drain the HPOP.
This usually holds around 24oz of oil. A small tube and syringe will do
fine. Once empty, you can then remove exhaust back pressure sensor. It
might be easier to remove the timing cover that the ebp is mounted on.
Its only two bolts and it comes right off.
 You can then remove the top
of the reservoir, exposing the pump drive gear.
 Below the reservoir in the
pump bolt cover. Remove this cover, then using an 18mm socket, you can
remove the pump drive gear. 
With the drive gear removed, remove all hoses and electrical connections
from the HPOP. Using a 10mm six point socket
remove the HPOP retaining bolts, and slide the HPOP out of
the truck. 
Ok...time to take a break and admire the carnage you've done to your
truck. LOL It's now time to do some bench work. First and
foremost...clean up the factory HPOP you just removed. It doesn't need
to be showroom shiny, but any oil globs, oil runs or dirt need to be
cleaned off. Be sure to organize what you removed from the truck and
have it set safely aside so no loss of parts occurs.
 Remove the Injection Pressure
Regulator (IPR) from the rear of the factory HPOP using a 1 1/8" 6 point
socket. Next remove the #6 hex plug on the rear of the factory pump with
an 11/16" wrench. Now remove the rear most high pressure fitting and
check spring on the driver side of the factory HPOP. Now...the hex plug
you just removed prior, re-install this plug into the high pressure port
you just opened up. With the kit, a black IPR plug was supplied that
needs to be inserted into the IPR port on the factory HPOP.
Lightly oil the rings first. Place
the shaft coupler supplied with the kit onto the front of the factory
HPOP.
 New orings were
supplied with the kit to re-ring the factory IPR you removed. Once done,
re-install the IPR into the back of the modified pump that came with the
kit. Don't forget to install the magnet, spacer and retaining nut on the
IPR valve, along with lightly oiling the orings at the same time. On the
supplied modified HPOP, ensure that the supplied O-ring is installed in
the rear, along with the #6 low profile hollow hex plug. The plug should
be installed in the third port at the back of the modified HPOP.
 Retrieve the aluminum pump
coupler and make sure its clean and free of debris. Place flat side down
on a towel, rag, or something soft and apply a bit of sealant to the
mounting surface that is facing up. Slide the modified HPOP down into
the billet pump coupler, making sure that everything is still aligned.
Tap (RUBBER MALLET ONLY!!!!!)
the nose of the pump to seat the pump, making sure that there is no
misalignment.  (a
bit tough to see in the previous picture, but the small white line is
the sealant) 
Once seated and aligned...this is what the assembly should look like.
Using the supplied studs 
ensure that the bolt holes on the modified HPOP are aligned with the
bolt holes of the pump coupler. Once done, take your factory pump and
lay it face up on your workbench. Place the supplied hpop gasket on the
face of the factory hpop, ensuring proper location. Place the billet
coupler the the modified hpop on the face of the factory hpop. Make sure
that all ports and bolt holes line up. You might need to do some slight
twisting to get everything seated.
*CAUTION...Before doing the next step, you need to ensure that the
gasket is still properly aligned. Damage to the gasket is possible if
not aligned...which will lead to oil leaks. Place the
supplied lock washers and and 13mm barrel nuts on the supplied studs,
and slide them into the pump assembly from the rear. Bench assembly is
now done and should look something like this.
 It's now time to put this bad
boy back on the truck. Make sure that the engine valley is clear of
obstructions, such as debris, wiring harnesses, fuel lines, small
Toyotas, such like that. Place the pump assembly in the valley, tail
first. Remember that the studs are not attached at this time, so they
may slide back on you. Depending upon your truck, you may have to
reposition the fuel filter bowl drain line to gain clearance.
 In my case, we had to trim
back the fuel drain line. This is not an issue as a short piece of fuel
line will replace the removed section. Place the second supplied hpop
gasket on the surface of the front pump...being very careful not to
damage any rubber. The rubber is soft and tears easily. Slide the entire
assembly forward into the hpop mounting location located on the timing
cover. *THIS NEXT PART IS EXTREMELY
IMPORTANT!!! Screw the studs into the pump bolt holes using a
4mm allen hex key until the bolt bottoms out. Stop there. The bolt holes
are aluminum and will strip easily if over tightened. Use a 13mm six
point deep socket to tighten the 13mm barrel nuts down to secure the
pump. You need to make sure that you tighten evenly. If the studs are
not tightened down the same, the pump will become cocked to one side,
putting added stress on the shaft, leading to premature wear or complete
failure. Tighten each nuts a couple of turns alternating back and forth
until they become snug. Then torque down to 20-25 lbs./ft. Once this is
done, take measurements from the pump mounting surface on the timing
cover to the billet coupler making sure the pumps are tightened evenly.
 Once the pump is tightened in
place, reinstall the pump gear. Be sure that the gear is completely
seated on the front shaft. Tighten the bolt to 95 lbs./ft with a 18mm 6
point socket. Put the pump bolt cover back on using a good sealant.
Now's going to be the time you wish you had small hands if you don't.
Install the 90 degree O-ring to the #6 JIC fitting and one 90 degree #6
JIC fitting into the back of the pump.
 Now install the straight
O-ring to #6 JIC fitting followed by a 90 degree #6 JIC fitting into the
rear pressure port of the front pump.
 Install the Z shaped tube
between the fittings with the black mark on the tube facing toward the
front of the truck. Tighten down, being careful not to over torque the
fittings. Install the driver's side hpop pressure line into the front
port of the front hpop, and the passenger side hpop pressure line into
the front port of the rear hpop.
 Take the brass "T" fitting
that was supplied and install into the oil temperature sensor mounting
hole. Be sure to rotate the fitting so the unused outlet is facing in a
direction that will have have no interference when the oil temperature
sensor is installed. There is a supplied 6 3/4" hose that goes between
the barbed fittings. Make sure that the clamps get put on the hose
before putting on the hose itself. And...make sure there are NO
KINKS in the hose at all.  In
the picture to the left, in the circle, you can see the "T" fitting that
the oil temp sensor is plugged into, and the end of the hose. A 45
degree fitting is installed into the empty drivers side port of the
billet pump couple, making sure the fitting is at the correct angle. You
now need to drill and tap the lid of the reservoir using an 11/32 drill
bit and an 1/8 npt pipe tap. Thankfully, a template was supplied with
the kit. Once the hole is drilled and tapped, make sure that the lid is
free of any metal shavings. Install the 1/8 npt to #6 JIC 90 degree
fitting into the threaded port. Make sure that the fitting has a layer
of yellow pipe tape placed on the threads of the npt only. And be sure
to use tape that is diesel fuel acceptable...which is the yellow type.
 Install the reservoir lid
back on. 
Make sure that the blue push lock hose supplied is a length of 12
inches. Install the two push lock hose ends onto each end of the hose.
Install one end of the hose into the passenger side barbed fitting on
the billet coupler, and the other end on the fitting you just installed
on the reservoir lid.  In
the previous picture...the white dash line represents what the normal
path of the hose would be. But because I installed a regulated return
kit at the same time, I had to re-route the hose. This resulted in
dremelling out the fiberglass holder that the fuel cover is mounted to.
 Re-attach the wiring harness
making sure that the IPR and ICP are secured correctly. Re-install all
the necessary components that you removed in the beginning, (CAC tubes,
crossover pipe, fuel filter bowl, fuel lines, etc). Double check all
connections, both hose and wiring. Prime the reservoir with clean engine
oil through one of the fittings on the lid to aid in starting the truck.
Its now time to wake the beast up. It may take a few cranks longer as
oil fills all the necessary lines. TaDa...You're done. Button everything
up, and take your vehicle for a test drive and see how it feels. |
|
At the last dyno event, my truck in stock form made
288hp/605 tq. These are pure uncorrected numbers. The dyno belonged to
Dave Dunbar. In a few weeks, I will be making the trek back down to
Tennesse and getting the truck back on the same dyno with the same dyno
operator. The only change made to the truck from the spring to now is
the addition of a regulated fuel system and the Stealth pump. Any hp/tq
increases from the fuel system will be negligible, so any and all
increases will be due to the pump. I will show differences in hp/tq
curves as well. Then you can decide for yourself if this is the real
deal or not. But I am fairly certain that the pump alone will have
pushed me into the 300+hp range. Now we just need to figure out how far
into that range I am.
*edit*
In September 2006, on my way down to
Smokin in the Smokies, I stopped in St. Louis and had Gary wire up the
second IPR. I then dyno'd the truck down in Tennessee. Jody Tipton of
DP-Tuner sat in the cab of the truck custom programming the truck to
take full advantage of the pump, while dyno operator Dave Dunbar flogged
the daylights out of my truck on his dyno. I'm guessing that we made at
least a dozen runs on the dyno trying to get every last pony out of the
truck. What you see below is a graph comparing the best dyno runs from
the Fall with the pump, to the runs in the Spring 2006 without the pump.
This is with corrections
added. The red HP line is from the spring, the blue HP line is
from the fall. You can see that my hp numbers with the pump kept
climbing and climbing...peaking out at 333.2 corrected HP. This is a
gain of 45.1HP simply due to the pump. Looking at the torque curves, its
the same. The red TQ line is from the spring, the blue TQ line is
from the fall. My torque increased 78.2 foot pounds with the pump. That
makes a huge difference pulling the camper. Hills weren't as big of
struggle...the camper towed so much easier...and my mileage increased
about 1/2 gallon per mile with the camper in tow. |
