1. Remove the fuel injection pump to fuel feed block fuel hose. Refer to Fuel Hose Replacement - Fuel Injection Pump to Fuel Feed Block.
2. Remove the air intake pipe. Refer to Air Intake Pipe Replacement.



3. Disconnect the engine wiring harness extension electrical connector (1) from the fuel pressure regulator. (wiring harness shown removed for clarity).



4. Clean the fuel pressure regulator and high pressure injection pump thoroughly with solvent, such as GM P/N 12377981 (Canadian P/N 10953463) or equivalent.
5. Using compressed air, thoroughly blow dry the regulator and pump.
6. Remove the fuel pressure regulator TORX® bolts (1) using a T25 TORX®.
7. Remove the fuel pressure regulator (2). (fuel lines removed for clarity).
8. If dirt or debris is found in the bore or seating surfaces of the fuel injection pump, perform the following:

•	Place a clean rag over the bore on order to collect the excess fuel.

•	Bump the engine over in order to flush any debris out of the regulator bore.

Note: If the pressure regulator is being re-used, check the O-rings for damage. If the O-rings are damaged, install NEW O-rings.

1. Lubricate and install NEW O-rings onto the regulator. Lubricate the O-rings with clean, NEW engine oil.

Note: If the regulator is installed at an angle the O-rings may be damaged, resulting in possible fuel leakage.

2. Install the fuel pressure regulator (2).

Caution: Refer to Fastener Caution in the Preface section.

3. Install the fuel pressure regulator TORX® bolts (1) using a T25 TORX®.

Tighten

•	Tighten the bolts a first pass to 4 N·m (35 lb in).

•	Tighten the bolts a final pass to 7 N·m (62 lb in).




4. Connect the engine wiring harness extension electrical connector (1) to the fuel pressure regulator.
5. Install the air intake pipe. Refer to Air Intake Pipe Replacement.
6. Install the fuel injection pump to fuel feed block fuel hose. Refer to Fuel Hose Replacement - Fuel Injection Pump to Fuel Feed Block.
7. Prime the fuel system. Refer to Fuel System Priming.
8. Start the engine. If the engine stalls, repeat the above step.
9. Once the engine starts, inspect for fuel leaks.