Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Verify none of the following conditions listed below exist:
- Damage, carbon tracking or fluid intrusion of the spark plug boots and/or spark plugs
- Vacuum hose splits, kinks and incorrect connections
- Engine vacuum leaks
- Crankcase ventilation system for vacuum leaks
- Fuel pressure that is too low or too high. Refer to Fuel System Diagnosis .
- Contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Exhaust system restrictions
  - If a condition exists
    Repair or replace as necessary.
  - If no conditions exist
Ignition OFF, remove the appropriate T 8 Ignition Coil from the spark plug and connect the EL 26792 HEI Spark Tester to the spark plug boot, engine Cranking.
NOTE: An erratic or weak spark is considered a no spark condition.
Verify the spark output.
- If no output or the output is weak
  Refer to Electronic Ignition System Diagnosis .
- If the output is good
Ignition OFF.
Verify the conditions listed below. Refer to Ignition System Specifications .
- The correct spark plug type
- The correct spark plug gap
- The correct spark plug torque
- If a condition exists
  Repair or replace as necessary.
- If no conditions exist
Exchange the suspect spark plug with another cylinder that is operating correctly.
Engine Running.
Verify the scan tool Cylinder 1 - 4 Current Misfire Counter does not increment for the cylinder where the suspect spark plug was installed.
- If increments
  Replace the spark plug.
- If does not increment
Test or inspect for the conditions listed below:
- A lean or rich Q17 Fuel Injector - Refer to Fuel Injector Diagnosis .
- An engine mechanical condition - Refer to Symptoms - Engine Mechanical .