PleasureCraft Engine Group 5.0L, Diagnostic Manual

Page: 115 / 337

5.0/5.7L Distributor Ignition 4A - 9
MEFI 4 - PCM
Spark Plug Replacement
Removal Procedure
1. Remove the spark plug wires. Refer to Spark Plug
Wire Replacement.
2. Loosen each spark plug one or two turns.
3. Brush or air blast away any dirt from around the
spark plugs.
4. Remove the spark plugs one at a time and place
each plug in a tray marked with the corresponding
cylinder numbers.
317307
Spark Plug Usage
•
Ensure that the correct spark plug is installed. An
incorrect spark plug causes driveability conditions.
•
Ensure that the spark plug has the correct heat
range. An incorrect heat range causes the following
conditions:
–
Spark plug fouling - colder plug
–
Pre-ignition causing spark plug and/or engine
damage - hotter plug
Spark Plug Inspection
•
Inspect the terminal post (1) for damage.
–
Inspect for a bent or broken terminal post (1).
–
Test for a loose terminal post (1) by twisting an
pulling the post. The terminal post (1) should NOT
move.
•
Inspect the insulator (2) for fl ashover or carbon
tracking, soot. This is caused by the electrical
charge traveling across the insulator (2) between
the terminal post (1) and ground. Inspect for the
following conditions:
622529
622530