How are ignition cap and rotor issues diagnosed?
Diagnosing any of the symptoms mentioned, for a distributor type ignition system, will normally being by checking all ignition components for abnormal conditions that may be indicative of failure. If nothing is found, the spark plug wires, distributor cap and rotor, and spark plugs, more or less in that order, will be removed, inspected, and diagnosed. If the spark plug wires are too resistant to electricity, the spark plugs are worn or fouled, or the distributor and rotor are worn, corroded, or oil fouled, those components would be diagnosed as faulty.
How is a ignition cap and rotor replaced?
If the distributor cap and rotor will be replaced, the spark plug wires will be replaced as well, unless they have been changed according to scheduled maintenance intervals, or they appear to have service life remaining. Likewise, and with the same exceptions, if the spark plug wires are being changed, the distributor and rotor will be changed. The spark plug wires will be marked for their location, and the new spark plug wires will be assembled with the spark plugs and ignition distributor cap using those markings. After the ignition distributor rotor is popped into place, the distributor cap will be installed, and the spark plug wires attached to mounting hardware.
RepairPal Recommendations for ignition cap and rotor issues
If completing this job as a DIY repair, mark the spark plug wires according to which position they sit on the distributor, and to which cylinder they supply power. When having these items changes at a repair facility, ask what type of parts are being used, if they conform to OEM standards, and specify if you prefer to use parts from the manufacturer.
What to look out for when dealing with ignition cap and rotor issues
Some ignition distributor cap and rotors are better than others at getting high voltage current to the spark plug wires efficiently. Purchasing ignition parts that are built to exact OEM standards or better is recommended. Purchasing inferior parts may lead to a repeated repair.