HMMWV – Injection Pump Replacement
The injection pump is the heart of your HMMWV. It is also one of the most common problem areas resulting in loss of power, rough running or inability to start. These vehicles can sit for years at a time with the valley of the engine filled with water causing your pump to corrode and cause problems. Even if your HMMWV starts and seems to run, you may be experiencing power loss due to an inefficient pump. The simplest solution to this is to replace your pump. This can be a daunting task, but hopefully this guide will help ease you through it with some tips and tricks.
1
Start removing the air Intake tube by first removing the two bolts holding it to the manifold and then the large clamps and remove the intake tube completely.
2
Remove the other end by loosening the large clamps and remove the intake tube completely.
3
Remove all electrical connectors and disconnect return hose from IP.
4
Remove return spring from IP
5
Unbolt accelerator cable from mount.
6
Remove clip holding acelerator cable from IP and move cable out of the way.
7
Remove all bolts holding down intake manifold
8
Remove intake manifold from engine (may be stuck)
9
Remove fuel output hoses from IP starting with the top connector.
10
Remove Fuel input hose.
11
Remove belt via tensioner
12
Remove pulley in front of oil fill tube
13
Remove oil fill tube by first removing bolts holding it on.
14
Using the hole exposed by removing the oil fill tube, rotate engine from underneath to line up first drive bolt from front of engine. It helps to have one person feel for the bolt head while another turns the engine from underneath.
15
When aligned, remove bolt using 7/16 socket (use magetic socket or be extremely careful to not drop bolt while removing)
16
Repeat steps 10/11 for bolts 2 and 3.
17
Remove 3 bolts holding IP to engine block.
18
Carefully remove IP from engine.
19
Remove and clean up old gasket from engine.
20
Transfer bracket from old IP to new
21
Transfer tdm from old IP to new
22
Place new gasket around bolts on engine block.
23
Locate keyhole on IP drive and adjust IP drive to line up with keyhole.
24
Insert IP key aligned with keyhole and verify alignment via front of engine. Be careful to make sure the key isn’t accidentally in the adjacent bolt-hole instead.
25
When bolt hole is aligned, insert the first bolt through the oil fill hole and tighten (do not force).
26
Rotate engine underneath and insert the other 2 bolts attaching the IP to the drive.
27
Attach the IP nuts attaching the IP to the block making sure the timing marks are aligned.
28
Attach the fuel input hose to the center of the rear of the IP.
29
Attach the fuel output hoses starting with the bottom.
30
Attach throttle cable and retention clip.
31
Attach throttle cable to mounting bracket.
32
Attach TDM cable and both electrical connectors.
33
Remount intake manifold and install all remaining bolts.
34