Ram 1500, 2500, 3500, 2WD and 4WD, 2001-2005

Spark Plugs

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Inspection



Chipped Electrode Insulator

A chipped electrode insulator usually results from bending the center electrode while adjusting the spark plug electrode gap. Under certain conditions, severe detonation can also separate the insulator from the center electrode. Spark plugs with this condition must be replaced.

Cold Fouling/Carbon Fouling

Cold fouling is sometimes referred to as carbon fouling. The deposits that cause cold fouling are basically carbon. A dry, black deposit on one or two plugs in a set may be caused by sticking valves or defective spark plug cables. Cold (carbon) fouling of the entire set of spark plugs may be caused by a clogged air cleaner element or repeated short operating times (short trips).

Electrode Gap Bridging

Electrode gap bridging may be traced to loose deposits in the combustion chamber. These deposits accumulate on the spark plugs during continuous stop-and-go driving. When the engine is suddenly subjected to a high torque load, deposits partially liquefy and bridge the gap between electrodes. This short circuits the electrodes. Spark plugs with electrode gap bridging can be cleaned using standard procedures.

Normal Operation

The few deposits present on the spark plug will probably be light tan or slightly gray in color. This is evident with most grades of commercial gasoline. There will not be evidence of electrode burning. On all engines, gap growth will not average more than approximately 0.025 mm (.001 in) per 3200 km (2000 miles) of operation. Spark plugs that have normal wear can usually be cleaned, have the electrodes filed, have the gap set and then be installed.

Some fuel refiners in several areas of the United States have introduced a manganese additive (MMT) for unleaded fuel. During combustion, fuel with MMT causes the entire tip of the spark plug to be coated with a rust colored deposit. This rust color can be misdiagnosed as being caused by coolant in the combustion chamber. Spark plug performance may be affected by MMT deposits.

Oil or Ash Encrusted

If one or more spark plugs are oil or oil ash encrusted, evaluate engine condition for the cause of oil entry into that particular combustion chamber.

Preignition Damage

Preignition damage is usually caused by excessive combustion chamber temperature. The center electrode dissolves first and the ground electrode dissolves somewhat latter. Insulators appear relatively deposit free. Determine if the spark plug has the correct heat range rating for the engine. Determine if ignition timing is over advanced or if other operating conditions are causing engine overheating. (The heat range rating refers to the operating temperature of a particular type spark plug. Spark plugs are designed to operate within specific temperature ranges. This depends upon the thickness and length of the center electrodes porcelain insulator.)

Scavenger Deposits

Fuel scavenger deposits may be either white or yellow. They may appear to be harmful, but this is a normal condition caused by chemical additives in certain fuels. These additives are designed to change the chemical nature of deposits and decrease spark plug misfire tendencies. Notice that accumulation on the ground electrode and shell area may be heavy, but the deposits are easily removed. Spark plugs with scavenger deposits can be considered normal in condition and can be cleaned using standard procedures.

Spark Plug Overheating

Overheating is indicated by a white or gray center electrode insulator that also appears blistered. The increase in electrode gap will be considerably in excess of 0.001 inch per 2000 miles of operation. This suggests that a plug with a cooler heat range rating should be used. Over advanced ignition timing, detonation and cooling system malfunctions can also cause spark plug overheating.

Wet Fouling Or Gas Fouling

A spark plug coated with excessive wet fuel or oil is wet fouled. In older engines, worn piston rings, leaking valve guide seals or excessive cylinder wear can cause wet fouling. In new or recently overhauled engines, wet fouling may occur before break-in (normal oil control) is achieved. This condition can usually be resolved by cleaning and reinstalling the fouled plugs.

Inspection & Gapping



Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug. Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable job of cleaning with a small, hand-held wire brush. Do not use a powered wire wheel to clean plugs.

If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%.

Check spark plug gap before installation. The ground (side) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag.


NOTE
NEVER adjust the gap on a used platinum type spark plug.

Always check the gap on new plugs as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate. A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all. Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained. Absolutely never attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.

Click image to see an enlarged view

Fig. Inspect the spark plug to determine engine running conditions

Inspect the spark plug to determine engine running conditions

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Fig. A variety of tools and gauges are needed for spark plug service

A variety of tools and gauges are needed for spark plug service

Click image to see an enlarged view

Fig. Removing the boot from the heat shield

Removing the boot from the heat shield

Click image to see an enlarged view

Fig. Checking the spark plug gap with a feeler gauge

Checking the spark plug gap with a feeler gauge

Click image to see an enlarged view

Fig. Adjusting the spark plug gap

Adjusting the spark plug gap

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Fig. If a standard plug is in good condition, the electrode may be filed flat-WARNING: do not file platinum plugs

If a standard plug is in good condition, the electrode may be filed flat-WARNING: do not file platinum plugs

Removal & Installation



On 3.9L V-6 and 5.2L and 5.9L V-8 engines, spark plug cable heat shields are pressed into the cylinder head to surround each cable boot and spark plug.

If removal of the heat shield(s) is necessary, remove the spark plug cable and compress the sides of shield for removal. Each shield is slotted to allow for compression and removal. To install the shields, align shield to machined opening in cylinder head and tap into place with a block of wood.

Each individual spark plug is located under each ignition coil. Each individual ignition coil must be removed to gain access to each spark plug. Refer to Ignition Coil Removal/Installation.

  1. Remove the engine cover.
    NOTE
    Prior to removing spark plug, spray compressed air around spark plug hole and area around spark plug. This will help prevent foreign material from entering combustion chamber.

  2.  
  3. Remove spark plug from cylinder head using a quality socket with a rubber or foam insert.
  4.  
  5. Always remove spark plug or ignition coil cables by grasping at the cable boot. Turn the cable boot 1 / 2 turn and pull straight back in a steady motion. Never pull directly on the cable. Internal damage to cable will result.
  6.  
  7. Inspect the spark plug condition.
  8.  

To install:


NOTE
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.


WARNING
Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap or a cracked porcelain insulator.


WARNING
When replacing the spark plug and ignition coil cables, route the cables correctly and secure them in the appropriate retainers. Failure to route the cables properly can cause the radio to reproduce ignition noise. It could cause cross ignition of the spark plugs or short circuit the cables to ground. Special Nomex® heat shields are also used on certain cables to prevent heat damage. These shields are wrapped around the cable. A slit is provided on the shield for removal and installation. Transfer these shields to the new cables as necessary.

  1. Start the spark plug into the cylinder head by hand to avoid cross threading.
  2.  
  3. Tighten spark plugs to 26-30 ft. lbs. (35-41 Nm).
  4.  
  5. Install the spark plug cables over spark plugs.
  6.  
  7. Install the engine cover.
  8.  

3.7L Engine

Each individual spark plug is located under each ignition coil. Each individual ignition coil must be removed to gain access to each spark plug. Refer to the Ignition Coil Removal & Installation procedure in this section.

  1. Remove necessary air filter tubing at throttle body.
  2.  
  3. Prior to removing ignition coil, spray compressed air around coil base at cylinder head.
  4.  
  5. Prior to removing spark plug, spray compressed air into cylinder head opening. This will help prevent foreign material from entering combustion chamber.
  6.  
  7. 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.
  8.  
  9. Inspect the condition of the spark plugs.
  10.  

To install:


NOTE
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.


NOTE
Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap or a cracked porcelain insulator.

  1. Start the spark plug into the cylinder head by hand to avoid cross-threading.
  2.  
  3. Tighten the spark plugs to 20 ft. lbs. (27 Nm).
  4.  
  5. Before installing ignition coil(s), check condition of coil O-ring and replace as necessary. To aid in coil installation, apply silicone to coil O-ring.
  6.  
  7. Install ignition coil(s). Refer to Ignition Coil Removal/Installation in this section.
  8.  

3.9L, 5.2L, 5.9L & 8.0L Engines

NOTE
The vehicles covered in this product may have heat shields, which were installed by the manufacturer, located around the spark plugs. These are designed to protect the spark plug boots from the intense heat of the exhaust manifold. If they are still in place, do not remove them. If they are not in place, be sure to inspect the boots more frequently.

  1. Mark all the spark plug wires near the cap with their cylinder number for identification purposes. On some models factory wires have the cylinder number already on them.
  2.  
  3. Grasp and twist the spark plug boot until the boot comes free of the plug. Do not pull on the wire.
  4.  
  5. Repeat for the other spark plug wires.

    Click image to see an enlarged view

    Fig. These heat shields, which were installed by the manufacturer, are designed to protect the spark plug boots from the intense heat of the exhaust manifold. If they are still in place, do not remove them. If they are not in place, be sure to inspect the boots more frequently

    These heat shields, which were installed by the manufacturer, are designed to protect the spark plug boots from the intense heat of the exhaust manifold. If they are still in place, do not remove them. If they are not in place, be sure to inspect the boots more frequently
  6.  
  7. Prior to removing the spark plug, spray compressed air around the spark plug hole and the area around the spark plug. This will help prevent foreign material from entering the combustion chamber.
  8.  
  9. Remove the spark plug using a quality socket with a rubber or foam insert.
  10.  
  11. Inspect the spark plug condition. Refer to Inspection & Gapping in this section.
  12.  

To install:

  1. Inspect the spark plug boot for tears or damage. If a damaged boot is found, the spark plug wire must be replaced.
  2.  
  3. Using a wire feeler gauge, check and adjust the spark plug gap. When using a gauge, the proper size should pass between the electrodes with a slight drag. The next larger size should not be able to pass while the next smaller size should pass freely.
  4.  
  5. Carefully thread the plug into the bore by hand. If resistance is felt before the plug is almost completely threaded, back the plug out and begin threading again. In small, hard to reach areas, an old spark plug wire and boot could be used as a threading tool. The boot will hold the plug while you twist the end of the wire and the wire is supple enough to twist before it would allow the plug to crossthread.
    WARNING
    Do not use the spark plug socket to thread the plugs. Always carefully thread the plug by hand or using an old plug wire to prevent the possibility of crossthreading and damaging the cylinder head bore.

  6.  
  7. Carefully tighten the spark plug. If the plug you are installing is equipped with a crush washer, seat the plug, then tighten about 1 / 4 turn to crush the washer.
  8.  
  9. Tighten the plugs to 26-30 ft. lbs. (35-41 Nm).
  10.  
  11. Apply a small amount of silicone dielectric compound to the end of the spark plug lead or inside the spark plug boot to prevent sticking, then install the boot to the spark plug and push until it clicks into place. The click may be felt or heard, then gently pull back on the boot to assure proper contact.
  12.  
  13. When installing a new set of spark plug cables, replace the cables one at a time so there will be no mix-up. Start by replacing the longest cable first. Install the boot firmly over the spark plug. Route the wire exactly the same as the original. Insert the nipple firmly into the tower on the distributor cap.
  14.  

4.7L Engine

Each individual spark plug is located under each ignition coil. Each individual ignition coil must be removed to gain access to each spark plug. Refer to Ignition Coil Removal/Installation.

  1. Remove necessary air filter tubing at throttle body.
  2.  
  3. Prior to removing ignition coil, spray compressed air around coil base at cylinder head.
  4.  
  5. Prior to removing spark plug, spray compressed air into cylinder head opening. This will help prevent foreign material from entering combustion chamber.
  6.  
  7. 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.
  8.  
  9. Inspect the condition of the spark plugs.
  10.  

To install:


WARNING
The 4.7L V-8 engine is equipped with copper core ground electrode spark plugs. They must be replaced with the same type/number spark plug as the original. If another spark plug is substituted, pre-ignition will result.


NOTE
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.


NOTE
Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap or a cracked porcelain insulator.

  1. Start the spark plug into the cylinder head by hand to avoid cross-threading.
  2.  
  3. Tighten the spark plugs to 20 ft. lbs. (27 Nm).
  4.  
  5. Before installing ignition coil(s), check condition of coil O-ring and replace as necessary. To aid in coil installation, apply silicone to coil O-ring.
  6.  
  7. Install ignition coil(s). Refer to Ignition Coil Removal/Installation in this section.
  8.  

5.7L Engines

Eight of the 16 spark plugs are located under an ignition coil; the other 8 are not. If spark plug being removed is under coil, coil must be removed to gain access to spark plug. Refer to Ignition Coil Removal/Installation.


NOTE
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. Refer to Spark Plug Cable Removal for a graphic.


NOTE
Before installing spark plug cables to either the spark plugs or coils, apply dielectric grease to inside of boots.

  1. Remove necessary air filter tubing at throttle body.
  2.  
  3. Prior to removing ignition coil (if coil removal is necessary), spray compressed air around coil base at cylinder head cover.
  4.  
  5. Prior to removing spark plug, spray compressed air into cylinder head opening. This will help prevent foreign material from entering combustion chamber.
  6.  
  7. Inspect the condition of the spark plugs.
  8.  

To install:


NOTE
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.
    WARNING
    The 5.7L V-8 is equipped with torque critical design spark plugs. Do not exceed 15 ft. lbs. (20 Nm) torque.

  2.  
  3. Tighten the spark plugs to 11-15 ft. lbs. (15-21 Nm).
  4.  
  5. Before installing spark plug cables to either the spark plugs or coils, apply dielectric grease to inside of boots.
  6.  
  7. To prevent ignition crossfire, spark plug cables MUST be placed in cable tray (routing loom) into their original position.
  8.  
  9. Install ignition coil(s) to necessary spark plugs. Refer to Ignition Coil Installation.
  10.  
  11. Install spark plug cables to remaining spark plugs. Remember to apply dielectric grease to inside of boots.
  12.  

 
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