5.8l. How can I remove old fuel pump and install a new one?

You need to check pressure in the fuel rail on the engine. I don't know the specifications, but it probably should have 40 to 50 psi with just the key on (engine not running) if the fuel pump and pressure regulator are working properly. If you don't have fuel pressure at the rail, the injectors cannot deliver fuel to the cylinders.

so that mean the old one is all ready removed.?
or did you mean all steps in the fsm for INJECTOR.
the steps are the same on all EFI fuel rail injectors.
you could google that or you tube it or read the FSM.

hide call keys from step 2 on, or very bad things can happen.
(wife or kids no aware of danger)
ill just cover the (basics)
1: per FSM , depressurize the system, in can be at 60PSI
parked. so avoid fuel in eyes, or a fire. we do that first.
gain access to rail under failure. (RUF) (no barking)
2: remove injector X , wire plug. (failing)
3: then detach the injector rail clamps the both rails off as one....
injector are all now loose, to pull off.
4: add new seals to new injector, and install in reverse order.

that's it, only the gain access , varies,... mostly.

last depressure steps:
run engine,
remove fuel pump relay, engine stalls. key off, hide keys!

next tje FSM words (just the OFF section)

1. Remove fuel tank filler tube cap.
2. Perform Fuel System Pressure Release Procedure.
3. Remove negative battery cable at battery.
4. Remove air duct at throttle body air box.
5. Remove air box at throttle body.
6. Disconnect fuel line latch clip and fuel line at fuel rail. A special tool will be necessary for fuel line disconnection.
7. Remove necessary vacuum lines at throttle body.
8. Disconnect electrical connectors at all 6 fuel injectors. Push red colored slider away from injector. While pushing slider, depress tab and remove connector from injector. The factory fuel injection wiring harness is numerically tagged (INJ 1, INJ 2, etc.) for injector position identification. If harness is not tagged, note wiring location before removal.
9. Disconnect electrical connectors at throttle body sensors.
10. Remove 6 ignition coils.
11. Remove 4 fuel rail mounting bolts.
12. Gently rock and pull left side of fuel rail until fuel injectors just start to clear machined holes in cylinder head. Gently rock and pull right side of rail until injectors just start to clear cylinder head holes. Repeat this procedure (left/right) until all injectors have cleared cylinder head holes.
13. Remove fuel rail (with injectors attached) from engine.

end expert.

alldata.com
login and read all steps. that be best , then ask questions?

Keep in mind that you have several components there:
- Fuel Pump Sender Assembly,
- Fuel Pressure Regulator,
- Fuel Rail Assembly, and
- Fuel Injectors.

1.- Fuel Pump (Sender Assembly) - TESTING
Refer to the accompanying charts for fuel pump diagnosis and testing.

The fuel injection system remains under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.



Fig. 3.1L engine OBD system check to be done before fuel pump relay circuit diagnosis




Fig. 3.1L engine fuel pump relay circuit diagnosis (1 of 2)




Fig. 3.1L engine fuel pump relay circuit diagnosis (2 of 2)




Fig. View of the fuel pressure test port (Schrader valve)-3.1L engine

A - 3.1L engine fuel system pressure test (1 of 4)
B - 3.1L engine fuel system pressure test (2 of 4)
C - 3.1L engine fuel system pressure test (3 of 4)
D - 3.1L engine fuel system pressure test (4 of 4)



Fig. The fuel pump/fuel sender module assembly is mounted in the fuel tank


2.- Fuel Pressure Regulator - REMOVAL & INSTALLATION

(the fuel pressure regulator, which is located on the fuel rail assembly)

NOTE: Before removing the fuel regulator assembly, place a clean shop towel under the regulator to catch any fuel drips

1. Properly relieve the fuel system pressure.
2. If not done already, disconnect the negative battery cable.
3. On the 3.1L engine, remove the intake manifold plenum, as outlined in .
4. On the 2.4L engine, remove the fuel rail. Refer to procedure earlier in this section.
5. Detach the vacuum line from the regulator.
6. Place a shop towel under the regulator to catch any fuel that may drip out. Unfasten the fuel pressure regulator retaining screw, then remove the regulator by twisting and pulling it from the fuel rail.
7. Remove and discard the O-ring seal. Inspect the filter screen for contamination and replace if necessary.
   

To install:

1. Prior to assembling the pressure regulator to the fuel rail, lubricate the new rail-to-regulator O-ring seal with clean engine oil.
2. Place the O-ring on the pressure regulator and install the pressure regulator to the fuel rail.
3. Install the retainer or coat the regulator mounting screws with an approved thread locking compound and secure the pressure regulator in place. Tighten the mounting screw to 76 inch lbs. (8.5 Nm).
4. If removed, install the fuel rail assembly to the engine.

WARNING The fuel return pipe must be connected before tightening the regulator retaining screw to prevent the regulator from rotating. Rotation of the regulator could damage the retainer and spacer bracket and lead to a fuel leak at the regulator inlet.

1. Connect the fuel feed line and return line to the fuel rail assembly, use a backup wrench on the fittings to prevent turning.
2. Attach the vacuum line to the regulator.
3. On the 3.1L engine, install the intake manifold plenum.
4. Connect the negative battery cable. Turn the ignition to the ON position for two seconds, then turn it to the OFF position for ten seconds. Turn again to the ON position and check for fuel leaks.

continue...

Removal & Installation


Exploded view of the fuel rail and injector mounting


Take care when servicing the fuel rail assembly to prevent dirt or contaminants from entering the fuel system. ALL openings in the fuel lines and passages should be capped or plugged while disconnected.

1. Before disassembly, clean the fuel rail assembly with a spray type cleaner such as AC Delco® X-30A, or equivalent. After removal, DO NOT immerse the fuel rail in liquid solvent.
   
2. Properly relieve the fuel system pressure and disconnect the negative battery cable.
   
3. Remove the air intake duct, as necessary for access.
   
4. Tag and disengage the fuel injector electrical connectors.
   
5. Disengage the fuel pressure regulator vacuum line, then tag and disengage all other necessary vacuum hoses.
   
6. Loosen and remove the fuel rail retaining bolts.
   
7. If necessary to remove the fuel rail assembly completely from the engine compartment, or to prevent stressing and damaging the fuel lines, disconnect the fuel lines from the rail assembly.
   
8. Carefully lift the fuel rail assembly and fuel injectors from the intake.
   
9. Carefully release and separate the fuel injectors from the rail assembly.
   
10. Remove and discard ALL old O-rings from the fuel injectors and, if disconnected, the fuel lines.
    

To install:

1. Lightly coat the new O-rings with clean engine oil, then position them to the injectors and, if applicable, fuel fittings.
   
2. Install the injectors to the fuel rail assembly.
   
3. Carefully install the fuel rail and injectors to the intake manifold. Make sure the injectors are properly seated in their bores, but DO NOT force them into position.
   
4. Install and tighten the rail retaining bolts to 62 inch lbs. (7 Nm).
   
5. If removed, connect the fuel lines to the rail assembly and secure the fittings.
   
6. Engage the fuel pressure regulator and any other vacuum lines, as noted during removal.
   
7. Engage the injector electrical connectors.
   
8. Connect the negative battery cable and cycle the ignition switch (without attempting to start the engine) in order to pressurize the fuel system, then check for leaks.
   
9. Install the air intake duct.
   

Removal & Installation

Removal:

1. Disconnect the negative battery cable.
2. Relieve the fuel pressure.
3. Raise and support the vehicle.
4. Remove the fuel tank; refer to the procedure outline in this section.
5. Remove the fuel pump retaining bolts.
6. Remove the fuel pump.

To Install:
7. Thoroughly clean the fuel pump-mounting flange.
8. Install a new gasket and place the pump into the tank.
9. Ensure that the fuel tubes face toward the fuel rail and tighten the retaining bolts to 80-107 inch lbs. (9-12 Nm).
10. Install the tank as outlined in this section.
11. Tighten the fuel tank bolts to 66-91 inch lbs. (7.6-10.4 Nm).
12. Tighten the fuel tank straps bolts to 22-30 ft. lbs. (29.7-40.7 Nm).
13. Tighten the skid plate bolts to 9.3-12.7 ft. lbs. (12.7-17.3 Nm).
14. Connect the negative battery.

REMOVAL:

1. Disconnect the fuel hoses from the fuel pump.
2. Remove the two mounting bolts, the fuel pump and the base insulator.
   1. Scrape any old gasket material from the cylinder head.
   INSTALLATION:
   
   
   1. Install new base gasket with suitable gasket sealer applied to both sides.
   2. Install fuel pump with base insulator using the two mounting bolts. Ensure that the fuel pump lever is properly aligned with the camshaft lobe.
   3. Connect fuel hoses to their proper nipples.
   4. Start engine and check for fuel leaks.

you stated new pump installed? fuel filter could be plugged from old pump going out.

The combination Fuel Filter/Fuel Pressure Regulator is located on the fuel pump module. The fuel pump module is located on top of fuel tank.

The filter/regulator may be removed without removing fuel pump module although fuel tank must be removed.

REMOVAL

1. Remove fuel tank. Refer to Fuel Tank Removal/Installation.
2. Clean area around filter/regulator.
3. Disconnect fuel line at filter/regulator. Refer to Quick-Connect Fittings for procedures.
4. Remove retainer clamp from top of filter/regulator. Clamp snaps to tabs on pump module. Discard old clamp.
5. Pry filter/regulator from top of pump module with 2 screwdrivers. Unit is snapped into module
6. Discard gasket below filter/regulator.
   1. Before discarding filter/regulator assembly, inspect assembly to verify that O-rings are intact. If the smallest of the two O-rings can not be found on bottom of filter/regulator, it may be necessary to remove it from the fuel inlet passage in fuel pump module.
   INSTALLATION
   
   1. Clean recessed area in pump module where filter/regulator is to be installed.
   2. Obtain new filter/regulator (two new O-rings should already be installed)
   3. Apply a small amount of clean engine oil to O-rings. Do not install O-rings separately into fuel pump module. They will be damaged when installing filter/regulator.
   4. Install new gasket to top of fuel pump module.
   5. Press new filter/regulator into top of pump module until it snaps into position (a positive click must be heard or felt).
   6. The arrow molded into top of fuel pump module should be pointed towards front of vehicle (12 O'clock position).
   7. Rotate filter/regulator until fuel supply tube (fitting) is pointed towards front of vehicle (12 O'clock position).
   8. Install new retainer clamp (clamp snaps over top of filter/regulator and locks to flanges on pump module).
   9. Connect fuel line at filter/regulator. Refer to Quick-Connect Fittings for procedures.
   10. Install fuel tank. Refer to Fuel Tank Removal/Installation.

WARNING: THE FUEL SYSTEM IS UNDER CONSTANT FUEL PRESSURE EVEN WITH THE ENGINE OFF. THIS PRESSURE MUST BE RELEASED BEFORE SERVICING FUEL TANK .

Two different procedures may be used to drain fuel tank (lowering tank or using DRB scan tool).

The quickest draining procedure involves lowering the fuel tank.

As an alternative procedure, the electric fuel pump may be activated allowing tank to be drained at fuel rail connection. Refer to DRB scan tool for fuel pump activation procedures. Before disconnecting fuel line at fuel rail, release fuel pressure. Refer to the Fuel System Pressure Release Procedure for procedures. Attach end of special test hose tool number 6541, 6539, 6631 or 6923 at fuel rail disconnection (tool number will depend on model and/or engine application). Position opposite end of this hose tool to an approved gasoline draining station. Activate fuel pump and drain tank until empty.

If electric fuel pump is not operating, tank must be lowered for fuel draining. Refer to following procedures.

FUEL TANK REMOVAL

1. Disconnect negative battery cable at battery.
2. Release fuel system pressure. Refer to the Fuel System Pressure Release.
3. Raise and support vehicle.
4. If Equipped: Remove fuel tank skid plate.
5. Remove 4 fuel hose shield mounting bolts and remove fuel hose shield from body.
   1. Remove fuel tank fill hose and vent hose clamps at fuel tank filler tube. Remove both hoses at fuel filler tube.
   2. Remove exhaust tailpipe heat shield mounting bolts and remove shield. CAUTION: To protect fuel tank from exhaust heat, this shield must reinstalled after tank installation.
   3. Place a hydraulic jack to bottom of fuel tank. WARNING: PLACE A SHOP TOWEL AROUND FUEL LINES TO CATCH ANY EXCESS FUEL .
      1. Disconnect fuel supply line from fuel extension line near front of fuel tank. Refer to Fuel Tubes/Lines/Hoses and Clamps. Also refer to Quick-Connect Fittings for procedures.
      2. Disconnect EVAP canister vent line near front of tank.
      3. Disconnect fuel pump module electrical connector (pigtail harness) near front of tank. Harness connector is clipped to body.
         1. Remove two fuel tank strap nuts. Position both tank support straps away from tank.
         2. Carefully lower right side of tank while feeding both fuel hoses through access hole in body. Fuel Tank Full And Not Drained Using DRB Scan Tool: To prevent fuel loss through hoses, keep left side of tank higher than right side while lowering. Do not allow hose openings to drop lower than top of tank.
         3. Continue lowering tank until clear of vehicle. Place tank on floor with left side (hose side) higher than right side
            1. Drain tank by removing fuel fill hose at tank. Fuel fill hose is largest of 2 hoses. Insert the drain hose (from an approved gasoline draining station) into hose opening. Drain tank until empty.
            2. If fuel pump module removal is necessary, refer to Fuel Pump Module Removal/installation for procedures.
            INSTALLATION
            
            1. If fuel pump module is being installed, refer to Fuel Pump Module Removal/installation for procedures.
            2. Install fuel fill/vent hoses to tank fittings. To prevent hose from kinking, rotate each hose until index mark on hose is aligned to index tang on fuel tank.
            3. Install hose clamps to hoses. Position clamps between index marks on each hose.
            4. Position fuel tank to hydraulic jack.
            5. Raise tank into position while guiding fuel fill and vent hoses into and through access hole in body.
            6. Continue raising tank until positioned to body.
            7. Attach two fuel tank mounting straps and mounting nuts. Tighten nuts to 10 Nm (90 in. lbs.) torque. Do not over tighten nuts.
            8. Install both fuel hoses to fuel fill tube. Tighten both retaining clamps.
            9. Position fuel hose shield to body. Install and tighten 4 mounting bolts.
            10. Connect fuel pump module pigtail harness electrical connector near front of tank.
            11. Connect fuel pump module supply line near front of tank. Refer to Quick-Connect Fittings for procedures.
            12. Connect EVAP hose near front of tank.
            13. Install exhaust tailpipe heat shield.
            1. Install fuel tank skid plate (if equipped).
            1. Lower vehicle and connect battery cable to battery.

Look on passenger side frame rail ahead of the rear wheel in a bracket with a fuel line on each end. Before starting replacement-- be sure to release pressure from fuel lines, by removing fuel pump fuse under hood and running engine to use gas from lines. I then remove fuel lines by moving clamps away from fitting so hose can be pulled loose from old filter while it is still in bracket. On top of mounting is a bolt that holds filter clamp in place . After removing clamp and filter from mounting bracket, loosen filter body clamp and slip oout old filter-- then in with the new filter. Then reverse your steps to install filter. After filter is back in place -- reinstall fuel pump fuse, turn on key for a few seconds for gas to refill lines, then start engine and check your installation to make sure you have no fuel leaks at line connections.

here is the answer,follow these steps one by one please: (1)relieve fuel pressure by using a fuel pressure gauge that also has a bleeder valve on it (2)disconnect the negative battery terminal (3)remove the intake manifold service cover (4)remove air intact duct between the air cleaner housing and the throttle body gasket.also remove the throttle body spacer bolts,remove the spacer and remove thegasket.discard the old gaskets. (5)Disconnect the fuel supply and return lines from the fuel rail. 960Disconnect the vacuum hose from the fuel pressure regulator. (6)Remove the nut that attaches the fuel rail end-point bracket retainer. (7)Disconnect the electrical connectors form all 8 fuel injectors and set the fuel injector harness aside. (8)Remove the fuel rail mounting bolts. (9)Remove the fuel rail and the fuel injectors as a single assembly. (10)Remove the fuel injectors one by one,by flipping up the U-clip retainer then pulling the injector from the fuel rail. (11)Remove the old O-rings from the injectors and be sure to use new ones when installing the new injectors. (12)Also use a new gasket when installing the spacer,also use a new throttle body gasket.>>when finished start car and check for leaks.and you're done.