Fuel Injector - Single

Remove and replace a single fuel injector on the 2008 Dodge Viper 8.4L V10, including fuel system depressurization, fuel rail access, injector extraction, and testing.

Warnings

Tools required

Parts

• Fuel injector × 1 — Use OEM specification for 8.4L V10
• Fuel injector O-ring kit (upper and lower) × 1 — Use OEM specification
• Fuel injector retaining clip × 1 — Use OEM specification if damaged

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure engine is completely cold to the touch
3. Disconnect negative battery cable and wait 2 minutes for airbag system capacitors to discharge
4. Place catch pan and shop towels under work area to contain fuel spillage
5. Have fire extinguisher rated for Class B fires readily accessible
6. Identify which cylinder's injector requires replacement (cylinders numbered 1-5 passenger side front to rear, 6-10 driver side front to rear)

Procedure

1. 1

   Relieve fuel system pressure
   Remove the fuel pump relay from the Power Distribution Center (PDC) located in the engine compartment near the battery. Refer to the PDC lid diagram or service manual to identify the fuel pump relay position for this vehicle. Attempt to start the engine; it will run briefly then stall as fuel pressure drops. Crank the engine for an additional 10 seconds to ensure all residual pressure is released. Turn ignition off and reinstall the fuel pump relay. Alternatively, attach a fuel pressure gauge to the fuel rail Schrader valve and slowly open the valve to bleed pressure into a catch container until gauge reads 0 PSI.
2. 2

   Remove engine cover and air intake components
   Remove the engine cover by releasing the integrated push-clips or fasteners securing it to the intake manifold. Depending on injector location, you may need to remove or reposition air intake tubes for access. Loosen hose clamps on any intake tubes obstructing access to the fuel rail on the affected cylinder bank. If working on rear cylinders, you may need to remove the air cleaner housing and intake tube assembly completely to gain adequate clearance.
3. 3

   Access fuel rail and disconnect fuel lines
   Locate the fuel rail on the cylinder bank containing the faulty injector. Locate the fuel rail serving the cylinder bank with the faulty injector; verify the rail configuration and crossover/return line routing against the service manual for this vehicle. Identify the fuel supply line connection at the front of the fuel rail. Using the appropriate fuel line disconnect tool, depress the locking tabs and carefully separate the quick-connect fitting. Be prepared for residual fuel spillage despite pressure relief. Place shop towels around the connection and have the catch pan positioned below. If the fuel rail has a fuel return or crossover line, disconnect it using the same procedure.
4. 4

   Disconnect fuel injector electrical connectors
   Locate the electrical connector on the target fuel injector. Press down on the connector locking tab (typically a sliding or flip-up tab on the top of the connector) while pulling the connector straight off the injector. If access is limited, use a small pick to release the locking tab. Inspect the connector terminals for corrosion or damage. For better access to rail mounting bolts, you may disconnect the injector connectors on that bank and carefully route the harness out of the way.
5. 5

   Remove fuel rail mounting bolts
   Locate the fuel rail mounting bolts securing the rail to the intake manifold. Refer to the service manual to determine the exact number of fuel rail mounting bolts for this vehicle before removal. Remove these bolts completely using the appropriate socket. Keep bolts organized for reinstallation. Note that the fuel rail is held down by these bolts and by the interference fit of the injectors in their bores. Do not force the rail up at this stage.
6. 6

   Remove fuel rail with injectors
   Carefully work the entire fuel rail assembly upward, applying even pressure at multiple points along the rail. The injectors are press-fit into both the fuel rail and the intake manifold bores with O-ring seals. Use a gentle rocking motion to break the seal, pulling straight up to avoid cocking the injectors at an angle. If the rail resists, do not force it—check for any missed fasteners or obstructions. Once the rail is free, lift it with all injectors attached and set it on a clean work surface padded with shop towels. Keep the rail supported so injectors are not hanging at extreme angles.
7. 7

   Remove target fuel injector from rail
   Locate the metal retaining clip securing the target injector to the fuel rail. This clip typically spans across the top of the injector body and locks into slots on the fuel rail. Use needle-nose pliers or a small screwdriver to carefully pry one end of the retaining clip up and out of its slot, then slide the clip off the injector. With the clip removed, grasp the injector body firmly and pull straight out of the fuel rail with a twisting motion to break the upper O-ring seal. The injector should release with moderate force. If it is stuck, gently rock it side-to-side while pulling—do not pry against the fuel rail.
8. 8

   Remove and inspect old O-rings and seals
   Remove both the upper O-ring (which seals into the fuel rail) and the lower O-ring (which sealed into the intake manifold bore) from the old injector. Use an O-ring pick or small flat-blade screwdriver to carefully roll the O-rings off without damaging the injector body grooves if the injector will be reused. Inspect the intake manifold injector bore for any remaining old O-ring material, debris, or damage. Use the O-ring pick to carefully extract any stuck seal fragments. Wipe the bore clean with a lint-free rag. Do not use abrasive materials that could scratch the sealing surface.
9. 9

   Prepare and install new fuel injector
   Unpack the new fuel injector and inspect it for shipping damage, ensuring the nozzle tip is clean and undamaged. Lightly lubricate the new upper and lower O-rings with clean engine oil or a small amount of gasoline—do not use petroleum jelly or silicone grease. Install the new O-rings into their respective grooves on the new injector body, ensuring they are fully seated and not twisted. Apply a thin coating of dielectric grease to the injector electrical terminal inside the connector body to prevent corrosion.
10. 10

    Install injector into fuel rail
    Align the new injector with its bore in the fuel rail, ensuring the electrical connector is oriented in the correct direction to match the harness routing. Press the injector straight into the rail bore with firm, even pressure until it is fully seated and the upper O-ring is compressed. The injector body should sit flush against the fuel rail mounting surface. Install the metal retaining clip by positioning it over the injector body and pressing both ends down into the fuel rail slots until you hear or feel them click into place. Verify the clip is fully engaged by attempting to pull the injector out—it should be firmly locked.
11. 11

    Reinstall fuel rail assembly
    Carefully lower the fuel rail assembly back into position, aligning all injector nozzles with their respective intake manifold bores. Press down evenly on the fuel rail, using a rocking motion to guide all injectors into their bores simultaneously. Ensure no injector cocks at an angle, which could damage O-rings or nozzle tips. Once all injectors are partially seated, press the rail firmly down until it is flush with the mounting surface. Install the fuel rail mounting bolts and tighten them in a cross-pattern to ensure even clamping force. Tighten to the manufacturer torque specification from the service manual for this vehicle.
12. 12

    Reconnect fuel injector electrical connectors
    Reconnect the electrical connector to the new fuel injector by aligning the connector and pressing it straight onto the injector terminal until the locking tab clicks into place. Tug gently on the connector to verify it is locked. Reconnect any other injector connectors that were removed for access. Ensure all connectors are fully seated and locked, and that no wiring is pinched or rubbing against sharp edges.
13. 13

    Reconnect fuel lines
    Reconnect the fuel supply line to the fuel rail by inserting the quick-connect fitting straight onto the rail connection until you hear and feel a distinct click. Tug on the line to verify it is locked—it should not pull free. If equipped with a return or crossover line, reconnect it using the same method. Wipe away any spilled fuel from the fuel rail and surrounding components.
14. 14

    Reinstall air intake components and engine cover
    Reinstall any air intake tubes, hose clamps, and air cleaner housing that were removed for access. Ensure all hoses are properly seated and clamps are tightened securely. Reinstall the engine cover by aligning the mounting points and pressing down until the fasteners click into place. Verify nothing is left loose or disconnected in the engine bay.
15. 15

    Prime fuel system and check for leaks
    Reconnect the negative battery cable. Turn the ignition key to the ON position (without starting the engine) and listen for the fuel pump to run briefly to prime the system. Turn the ignition off, then repeat this cycle 3-4 times to build fuel pressure. Carefully inspect all fuel connections, the new injector O-ring areas, and the fuel rail for any signs of fuel leakage. Use a clean rag to wipe suspected areas and check for wetness. If no leaks are observed, start the engine and allow it to idle. Inspect again for leaks while the engine is running. Monitor the engine for smooth idle and proper operation. If the engine runs rough initially, allow it to run for 1-2 minutes as the ECU adjusts fuel trims.

Reassembly

1. Reassembly is covered in the procedure steps above
2. Ensure all fuel connections are secure and leak-free before operating the vehicle
3. Torque all fasteners to specification (fuel rail bolts to 8-10 lb-ft if specification not confirmed)

Verification

• Start engine and verify smooth idle with no misfires or rough running on the affected cylinder
• Check for fuel leaks at fuel rail connections and around the replaced injector with engine running
• Use a scan tool to check for any fuel injector-related fault codes
• Test drive the vehicle to confirm normal acceleration and no hesitation under load
• Recheck for fuel leaks after test drive when engine is hot
• Monitor fuel trims with a scan tool to verify the new injector is operating within normal parameters (typically ±5-10%)

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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