Misfire General Checks: Overview
Check Engine AreaCheck over engine area looking for signs of loose connectors, vacuum lines or evidence of leakage. Correct any problems found.
Check Ignition System
The general condition of the ignition system is best checked with the scope. The observation of the scope patterns will give you the relationship of voltage to time. The Digital Secondary KV function of TestBook will measure an average of ten firing cycles. Set the engine to 1600 RPM to obtain reading.
The following information will be useful in understanding the results of scope analysis. They are located in section 1-01 of the Operation Pride manual:
^ Plug firing time
^ Rich fuel mixtures
^ Lean fuel mixtures
^ Spark time
^ Valve action fluctuation
If this check shows the ignition system to be in good condition, it is not necessary to check the system further. If in doubt, proceed with the checks below.
Physical and resistance checks
1. Check spark plug wires for damage or looseness.
2. Wires can be checked end to end through the coil. Resistance should be 24-40 kOhms. If out of specification, measure coil and wires separately.
3. Secondary resistance of coils should be 13 kOhms. Spark plug wires should be 3-6.5 kOhms per foot.
4. while plug wires are out of their positions, inspect coil towers for evidence of damage, carbon tracking, etc. Replace any damaged components.
5. Check all primary circuit wires for tightness, damage, or corrosion. Repair or replace as necessary.
6. Pull spark plugs and check condition. Take note of color and condition.