I replaced my stock injectors with some Diesel-Central.com custom injectors. I think they are comparable to Hypermax Stage II but may flow slightly more. Here is a brief how-to on injector replacement.
Removal:
I have added an intercooler on my truck so I have a few more pieces than most 94-97's to remove. But the obvious first step is to remove any intercooler pipes, manifold can stay, that are in the way of the valve covers. Remove the valve covers. A 13mm socket is needed, with the rear bolts the hardest to get to. Drivers side is a little easier, and is accessible with a universal socket. The passenger side is a pain, but if I had to do it again, I would remove the vacuum canister on the A/C - HVAC system. It may be covered by the insulation wrap. Regardless of when you do this, it must be done to remove the rear passenger side injector. I did this later, but now I realize the bolt would come out easier if it is removed first. Once all bolts are removed, remove the valve cover. Disconnect the four wire harnesses that plug into the valve cover gasket. The harness inside gasket also is plugged into the gasket and needs to be unplugged. Remove the gasket when all 8 connectors are removed. Fold back the metal retaining clips that hold the connector to the injector. Next, pull on the connector that plugs into the glow plug. Once all connectors are removed, remove the wire harness.
Now you want to drain the oil passages to remove as much oil as possible. I did not do this, and let me say I wish I did. Remove the 2 brass bolts that require a torx bit. They are located at the top of head and can be found on almost any of these photos. Once drain, you can move on. Remove the small alluminum oil deflectors located on each injector with a metric allen wrench, forgot the size. Next, with an 8mm wrench, remove the bottom injector retaining bolt. The top retaining bolt does not need to be removed. With a small pry bar or a screw driver reach underneath the injector retaining color and pry up the injector. It shouldn't take too much pressure, but be careful not to pop the injector out too quickly and damage it on the fall. Try to soak up as much oil in each injector opening as possible with some rags.
The glows plugs need to be removed so later you can clean the cylinders of any oil that leaked in. The require a 10mm deep socket. A 3/8 drive kept rubbing on the push rods, so try a 1/4 drive.
Install:
Make sure each injector o-ring is oiled plenty before install. You shouldn't use the old o-rings either. The install procedure is basically the opposite of the removal. Place the injector in the head and gently tap with a rubber mallet. Torque the bottom retaining bolt to required amount (9ft-lbs I think). Replace the oil deflector tubes.
At this point you will need to blow the oil out of the cylinders. Place a lot of rags on top of the cylinders to soak up any oil that will blow out of each glow plug opening. BE CAREFUL, this oil will shoot out at very high speeds! Once you have rags to soak up the oil in place, use a metal object to BRIEFLY crank the engine slightly. Do several small cranks until you see the oil amount to lessen then give it a good few cranks. Fuel will continually spit out as you crank, do not confuse this with oil.
Once all the oil is out, replace the glow plugs. Attach the wire harnesses. Attach the valve cover gasket. Replace the valve cover. Replace the vacuum canister. Reattach any other items you removed.
Restarting the motor requires a LOT of cranking. Crank for about 10-15 seconds then let the starter motor cool. It took me about a dozen of these attempts. It will smoke quite a bit until everything is burned up and the oil pressure stabilized. It will also take a fair amount of miles until the system is fully recovered.
I'm not a novelist, so if I brisked over some topic, send me an email.
Misc pictures:
Engine apart
