Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Spark Plug Wires



See Figures 1 and 2

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Fig. Fig. 1: Checking plug wire resistance through the distributor cap with an ohmmeter

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Fig. Fig. 2: Checking individual plug wire resistance with a digital ohmmeter

At every tune-up/inspection, visually inspect the spark plug cables for burns, cuts or breaks in the insulation. Check the spark plug boots and the nipples on the distributor cap and coil. Replace any damaged wiring. If no physical damage is obvious, the wires can be checked with an ohmmeter for excessive resistance.

Every 50,000 miles (80,000 km) or 60 months, the resistance of the wires should be checked with an ohmmeter. Remove the distributor cap and leave the wires connected to the cap. Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather. Connect one lead of the ohmmeter to the corresponding electrode inside the cap and the other lead to the spark plug terminal (remove it from the spark plug for the test). Replace any wire which shows over 50,000 ohms. Generally speaking, however, resistance should run between 35,000-50,000 ohms.

Test the coil wire by connecting the ohmmeter between the center contact in the cap and either of the primary terminals at the coil. If the total resistance of the coil and the cable is more than 25,000 ohms, remove the cable from the coil and check the resistance of the cable. If the resistance is higher than 15,000 ohms, replace the cable. It should be remembered that wire resistance is a function of length and that the longer the cable, the greater the resistance. Thus, if the cables on your car are longer than the factory originals, resistance will be higher and quite possibly outside of these limits.


See Figures 3 and 4

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Fig. Fig. 3: Grasp the spark plug wire by its boot, then gently twist and pull to remove

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Fig. Fig. 4: This short wire runs from the distributor to the nearby ignition coil

When installing a new set of spark plug cables, replace the cables one at a time so that you can match up the length of each old plug wire with the new ones and there will be no mix-up. Start by replacing the longest cable first. Install the boot firmly over the spark plug. Route the wire exactly the same as the original. Insert the nipple firmly into the tower on the distributor cap. Repeat the process for each cable.

On the CA16DE and CA18DE Pulsar engines, no spark plug wires are used.