Typical defects of the distributor cap
1. Cracks in the wire lead; 2. Cover cracks; 3. breakdown; 4. Erosion of electrodes; 5. Wear of coal
Check and replacement
1. High voltage spark plug wires should be checked (and change if necessary) at the same time as changing spark plugs.
2. The easiest way to check is to inspect the wires with the engine running in a darkened garage. When glow is detected (breakdown) replace wires. Check the condition of the distributor cap and slider.
3. To check and clean the wires, disconnect each wire individually. On older vehicles, you will need to remove the trim on the cylinder head cover. Disconnect the wire on the distributor cap. Check the condition of the wire contacts and seals. Wipe the wires. Do not bend the wire strongly, as the conductive core may break. If cracks, traces of breakdown and burning of the wire are found, replace it.
4. Check for corrosion on wire lug connectors (at both sides) and conclusions of candles. Check the strength of the plug connection by putting a wire tip on the spark plug and shaking it. If the connection is loose, tighten the contact petals.
5. Turn away screws of fastening and remove a cover of the distributor of ignition. Wipe the cover clean and check for cracks inside and outside of the cover, signs of surface breakdown (thin charred paths), wear, burning and loosening of contacts (see fig. Typical defects of the distributor cap).
6. Remove the slider (photo on the left) and inspect in the places indicated by the arrows in the photo on the right.
7. If an old cap is installed, then check the resistance between the cap output and the spark plug. If the resistance is too high, replace the cap and wire. Change each wire individually.