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TDG Mafia Member #21
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Discussion Starter #1
VP44 replacement
Read these directions completely before you start. Look at your engine and read it again. Step 11 under installation requires some advance planning.

Tool list
3/8 ratchet
1/2 ratchet
8" 3/8 extension (wobble is best)
3/8" drive 10mm socket
11mm deep socket
15mm socket
13mm socket
19mm (or 3/4) wrench (angle is best)
17mm wrench
8mm wrench or 1/4" drive socket)
T-50 torx
Small "T" puller or gear puller
Oil filter wrench (looks like a pair of pliers) or strap wrench
1/2" drive 24mm socket (alternator nut)
1/2" drive 27mm socket (vp44 axle nut)
3# retrieval magnet
Inspection mirror
Catch pan

1. Either disconnect the batteries, or cover the drivers side battery with a fender cover
2. Loosen the top intercooler boot clamp on the intake hat.
3. Remove the 5 10mm bolts on the intake hat (4 hold down and one for the oil dipstick). Remove the intake hat and place on the work bench. Lift the grid heater and lay it over on the PDC (next to the battery)
4. Using a piece of bailing wire or the like, pull the intercooler tube over to the drivers battery and secure it out of your way (wire to the battery hold down clamp).
5. Remove the 3 13mm bolts on the TPS housing. Lift up and disconnect the wire harness. If your unit has the harness holder on it, use a flat blade screwdriver to open it and lay the TPS housing by the gird heater.
6. Remove the first three 10mm bolts that hold the injector lines down to the engine, starting from the front of the engine.
7. Disconnect the two wire harness connectors on the fire wall to give you more work room to cyl. 5 and 6.
8. Disconnect the VP44 wire harness
9. Now I like to get the fuel filter out of the way for more room, so I remove the rear 17mm banjo from the fuel filter (line from the LP). You can skip these (***) fuel filter steps if you wish) You are going to want to place a catch pan ender the engine.
10. Drain the fuel filter into a catch pan – water drain, make sure you close it when it is drained (***)
11. Remove the two 10mm mounting bolts holding the fuel filter. (***)
12. Remove the 8mm bolt, cap, and blue bushings on the injector line clamp just in front of the lifting eye by cylinder #5.
13. Release the clamp on the crank case breather hose and remove the hose.
14. Using the oil filter pliers, unscrew the crank case breather on the timing cover and remove.
15. Remove the 27mm nut on the VP44 axle. Using a 3# magnet or better, grab the lock washer on the axle and remove ***DO NOT DROP IT DOWN THE TIMING COVER***
16. Emergency brake on, vehicle in neutral or park, use the 24mm socket on the alternator pulley and rotate the engine CCW until the notch on the VP44 timing gear is at 12 o’clock. Inspection mirror and a flashlight is handy.
17. Use the T-puller to separate the timing gear from the VP44 axle. Two threaded holes in the gear. It will “pop” and move back and forth when free. Remove the puller. More detailed info as posted by MACHINEST - The gear stays in the housing, make sure the key is at 12:00, there is 2 ea drilled and taped holes in the gear, back the nut off about 3/16 of an inch,put a puller on the gear and pop it losse,then take the nut and washer off,have a screw driver at the end of the pump shaft when doing this,because you don't want to drop the nut and washer in the gear very carefull when putting the pump back into the gear,woodriff key,and if not lined up perfict you will roll the key out of the pump and if will fall you know where...A good lite and a small mirrow should help.....
18. Remove the 17mm banjo from the VP44 fuel supply from the filter. Catch the washer on the inside.
19. Lay the fuel filter down in the bottom of the engine compartment out of the way. (***)
20. Remove the 19mm banjo return valve from the VP44. Catch the washer on the inside.
21. Use the 19mm wrench to unscrew the injector lines at the valve cover.
22. Looking at the back of the injection pump, top is 12 o’clock, battery is 9, unscrew the 6, 7:30, and 9:45 injector lines and remove (should be cylinders 1,2, and 4).
23. Unscrew the 12, 4:30 and 2:15 (in this order is easiest) and remove.
24. Using the 15mm socket and extension, remove the four nuts on the VP44. Two outside (battery side) and two inside (block side).
25. Using the 13mm socket remove the two lower bolts on the rear support bracket (block side next two the PS pump). Now I have seen 10mm, and 15mm bolts down there, depending on year. Sometimes only one.
26. Remove the VP44.
27. Now on the 98.5 – 2000, there was a rear support bracket that was a real poor design and broke. If you encounter this (yours is broke), you will need to replace it and there is some work involved. YOU MUST HAVE THE REAR SUPPORT!!! If yours is broken, and you do not replace it, you will trash your pump.
28. Set the old pump upside down on your bench next to the new one. Make sure they are oriented the same. Transfer the support plate from the old pump to the new.
29. Stand both injection pumps on end and clock the two axles the same. The top of the injection pump (circuit board) being 12 o’clock, and if you rotated the engine, your old pump key way should be at about 10:45. DO NOT TURN THE OLD PUMP SHAFT!!!
30. Using a paint marker, or some sort of bright color paint, color the front edge of the key, and a straight line down the shaft threads to the tip of the axle on the new pump. This will help you make sure it is aligned correctly when you install.
31. Make sure the new pump has the o-ring installed on the mounting flange.
1. Set the new pump into position and insert into timing gear. Start 1 or 2 of the 15mm nuts on the studs to hold the pump in position.
2. Using the inspection mirror and light, look at the gear from the front of the engine and see if the line you painted is lined up with the notch in the gear. You should be able to see the front edge of the key through the notch. If not, remove the pump and adjust. DO NOT CONTINUE UNTIL YOU GET IT LINED UP. If the key is “almost there, only a 64th of an inch off” it is not there. It is possible to press the gear onto the pump with the key not aligned and really screw things up.
3. Snug up all 4 15mm nuts on the mounting studs.
4. Set the new lock washer and nut on the VP44 axle, and snug (35 ft #)
5. Remove the nut and washer (DO NOT DROP WASHER INTO TIMING COVER) and verify that the key is in the notch 100% lined up. If not, remove pump and inspect key for damage and adjust clocking, return to step 1.
6. Once the key is verified, install the two rear support bolts and tighten, torque the injection pump axle nut to 125# and tighten the 4 15mm mounting nuts.
7. Install the injector lines in reverse of removal (block side first) Tighten the valve cover ends finger tight, then back off ½ turn.
8. Mount the fuel filter back into position and install the banjos (filter and VP44).
9. Install the fuel return valve and line to the VP44.
10. Connect the VP44 wire harness
11. Now, I have a tool at work that hook up to the LP to run it constantly. After I have the feed lines connected to the VP (filter installed and return line) I connect the pump to the battery and start priming the system. You can use a “T” pin to back probe the POSITIVE side of the LP wire harness and a jumper wire to the battery positive, and the NEGATIVE side to ground (red wire + black wire - if you have a new extension). VERIFY WHICH IS POSITIVE IF YOU DO THIS BEFORE YOU START!!! You can cook your pcm if you do the wrong wires. You can prime by “bumping” the starter for the 30 second LP run time. I decided this was a PITA going back and forth from the engine to the ignition 15 or 20 times.
12. With the pump running, watch all the valve cover end injection lines for fuel. It will typically do 2 at a time, starting at #3. Wiggle the lines in and out to let the fuel/air out. Once you get good fuel flow, no bubbles, tighten the lines up and rotate the engine via alternator CCW (about ½ to ¾ turn on the alt) continue this until all 6 lines are bled. I will start assembling the other removed parts in reverse of removal as I do this (waiting for the air to bleed out) Skip the rotating the engine via the alternator if your are doing the bump the starter method
a. Crank breather valve, and hose
b. Hand thread the injector line mounting bolts
c. Grid heater and intake hat (only after #2 is bled and tightened)
d. Connect the wire harness’ at the fire wall (only after 5 and 6 are done)
e. TPS housing (only after #1 is bled and injector line mount is tightened)
13. Once all the lines are bled, tighten the injector mounting bolts, and the 8mm bolt, and blue bushings. Remove the pump power bypass if you used this method.
14. Verify that everything is installed and tightened up. Start the engine.
15. If you are having difficulty starting, you may have to crack open the injector lines on 1, 3, 4, and maybe 5. and crank the engine until you have good fuel flowing at the injector lines. Tighten them back up and try to start again.
16. Once the engine is running, visually verify that there are no fuel leaks. DO NOT CHECK FOR LEAKS BY HAD WITH THE ENGINE RUNNING!!!
17. Go to the car wash to wash off the fuel drippins from the engine and go for a 5 minute drive. Verify that there are no fuel leaks. # 6 is notorious for leaks (because you can’t get it tight enough due to lack of room to work).

This is a “Do it at your own risk” list of suggested procedures. The author accepts no responsibility for any individual attempting to perform repairs on their own vehicle if injuries or damages occur.

Premium Member
4,158 Posts
nice write up Alex. :Thumbup:

88 Posts
let me just emphasize at the end of step 15. Keep cranking until it starts...........Sometimes they are hard to refire after having the entire fuel system open. I've lost count of how many times I've had someone call in a panic because it wont fire!

1 Posts
thanks this was is and is going to be a great help

I just want to say thanks for this info this will save me about $800 if i dont mess up puting it in thanks:sly: :thanks:
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