5.7L V-8 HEMI ENGINE (2005 models)








Spark plug/coil wire harness assembly. When the plugs fire after compression for the cylinder on the power stroke, the companion cylinder on the opposite bank fires during the exhaust stroke, requiring only eight ignition coils to fire all 16 spark plugs.


The 5.7L V-8 engine is equipped with 16 spark plugs. Two plugs are used for each cylinder. The 5.7L is also equipped with 8 separate and independent ignition coils. The one-piece coil bolts directly to the cylinder head cover and attaches the coils secondary output terminal directly to a spark plug using a rubber boot seal. Each coil is also equipped with a second output terminal. This second terminal connects a conventional spark plug cable directly to a spark plug on the opposite cylinder bank. A separate primary electrical connector is used for each coil.

Eight conventional spark plug cables are used with the 5.7L. These cables connect a coil on one cylinder bank, directly to a spark plug on the opposite cylinder bank. The cables are placed and routed in a special plastic loom to keep them separated. This loom is clipped to the intake manifold. To prevent a mismatch of cables, a corresponding spark plug / coil number is displayed on each plug cable: 1/6, 2/3, 4/7 and 5/8. These numbers and can also be found on the top of the intake manifold to the right of the throttle body.

Two knock sensors (one for each cylinder bank) are used to help control spark knock.

The 5.7L engine does not use a conventional distributor.

The ignition system consists of:


  • 16 Spark Plugs (2 per cylinder)
  • 8 Separate, Dual-Secondary Output, Ignition Coils
  • 2 Knock Sensors
  • 8 Secondary Ignition Cables
  • Powertrain Control Module (PCM)
  • Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft Position, Throttle Position, 2 knock and MAP Sensors.



5.7L V-8 HEMI ENGINE (2006-2010 models, plug cables eliminated)


The 5.7L V-8 engine is equipped with 16 spark plugs. Two plugs are used for each cylinder. The 5.7L is also equipped with 8 separate and independent ignition coils. The one-piece coil bolts directly to the cylinder head cover and attaches the coils secondary output terminal directly to a spark plug using a rubber boot seal. A separate primary electrical connector is used for each coil.

Two knock sensors (one for each cylinder bank) are used to help control spark knock.

The 5.7L engine does not use a conventional distributor.

The ignition system consists of:


  • 16 Spark Plugs (2 per cylinder)
  • 8 Separate, Dual-Secondary Output, Ignition Coils
  • 2 Knock Sensors
  • Powertrain Control Module (PCM)
  • Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft Position, Throttle Position, 2 knock and MAP Sensors.


Spark plug installation and removal

Removing plugs - 5.7L and 6.1L engines


5.7L note (2005 models only):
Before removing or disconnecting any spark plug cables, note their original position. Remove cables one-at-a-time. To prevent ignition crossfire, spark plug cables MUST be placed in cable tray (routing loom) into their original position. See diagram and information below.

Each individual spark plug is located under each ignition coil. Each individual ignition coil must be removed to gain access to each spark plug. The coil mounts to the top of the valve cover with two bolts. The bottom of the coil is equipped with a rubber boot to seal the spark plug to the coil. Inside each rubber boot is a spring. The spring is used for a mechanical contact between the coil and the top of the spark plug.

1. Remove necessary air filter tubing at throttle body.

2. Prior to removing ignition coil, spray compressed air around coil base at cylinder head.

3. Depending on which coil is being removed, the throttle body air intake tube or intake box may need to be removed to gain access to coil.

4. Unlock electrical connector by moving slide lock first. Press on release lock while pulling electrical connector from coil.

5. Clean area at base of coil with compressed air before removal.

6. Remove two mounting bolts (note that mounting bolts are retained to coil).

7. Carefully pull up coil from cylinder head opening with a slight twisting action.

8 Remove coil from vehicle.

9. Prior to removing spark plug, spray compressed air into cylinder head opening. This will help prevent foreign material from entering combustion chamber.

10. Remove spark plug from cylinder head using a quality socket with a rubber or foam insert. Also check condition of ignition coil o-ring and replace as necessary.


Installing plugs - 5.7L and 6.1L engines

Special care should be taken when installing spark plugs into the cylinder head spark plug wells. Be sure the plugs do not drop into the plug wells as electrodes can be damaged.

1. Start the spark plug into cylinder head by hand to avoid cross threading aluminum threads. To aid in installation, attach a piece of rubber hose, or an old spark plug boot to spark plug.

2. The 5.7L and 6.1L engines are equipped with torque critical design spark plugs. Tighten spark plugs to 12-14 Ft. lbs. Do not exceed 15 ft. lbs. torque.

3. Install ignition coil(s) to necessary spark plugs.

4. Using compressed air, blow out any dirt or contaminants from around top of spark plug. Before installing spark plug cables to either the spark plugs or coils, or before installing a coil to a spark plug, apply dielectric grease to inside of boots.

5. Position ignition coil into cylinder head opening and push onto spark plug. Twist coil into position.

6. Install 2 coil mounting bolts.

7. Connect electrical connector to coil by snapping into position.








5.7L engine - coil parts and removal



Plug wires - 2005 model 5.7 engines





Spark plug cables on the 5.7L engine are paired on cylinders 1/6, 2/3, 4/7 and 5/8. Before removing or disconnecting any spark plug cables, note their original position . Remove cables one-at-a-time. To prevent ignition crossfire, spark plug cables MUST be placed in cable tray (routing loom) into their original position. The cable retention clips (6) and (8) must also be securly locked. If cable tray removal is necessary, release the 4 tray-to-manifold retention clips.




1 - #8 COIL-TO- #5 SPARK PLUG (MARKED 5/8)
2 - #7 COIL-TO- #4 SPARK PLUG (MARKED 4/7)
3 - #5 COIL-TO- #8 SPARK PLUG (MARKED 5/8)
4 - #3 COIL-TO- #2 SPARK PLUG (MARKED 2/3)
5 - #1 COIL-TO- #6 SPARK PLUG (MARKED 1/6)
6 - CLIPS (TRAY-TO-MANIFOLD RETENTION)
7 - CABLE TRAY
8 - CLIPS (SPARK PLUG CABLE-TO-TRAY- RETENTION)
9 - #2 COIL-TO- #3 SPARK PLUG (MARKED 2/3)
10 - #4 COIL-TO- #7 SPARK PLUG (MARKED 4/7)
11 - #6 COIL-TO- #1 SPARK PLUG (MARKED 1/6)