Parts for your 1991 Mitsubishi Pajero-Ignition leads

1991 Mitsubishi Pajero ignition leads: what they do and when to change them

Based on factory and aftermarket technical literature, ignition leads are fitted to petrol versions of the 1991 Mitsubishi Pajero, but not to the diesel variants. The Mitsubishi Pajero NH–NJ Workshop Manual (Mitsubishi Motors Corporation, c.1991–1994) and Gregory’s/ Haynes repair guides for Pajero/Montero of the same era describe distributor-type ignition systems with high-tension (HT) leads on the 4G54 2.6L four-cylinder and 6G72 3.0L V6 petrol engines. By contrast, the 4D56 2.5L turbo-diesel is a compression-ignition engine that uses glow plugs rather than spark ignition, so it has no ignition leads.

For owners of petrol 1991 Pajeros, the ignition leads do the quiet heavy lifting every time the key is turned. They carry high-voltage energy from the ignition coil and distributor to each spark plug, so the engine lights off cleanly and pulls well under load. On the V6, there are six plug leads plus a coil-to-distributor lead, on the 2.6 four-cylinder, there are four plus the coil lead. Heat, oil vapour, and age slowly harden the lead insulation and boots, which can cause misfires, a lumpy idle, hesitation on hills, and higher fuel use. At night, a faint ticking or visible arcing around the leads can be a give-away that they’re leaking spark.

As part of routine servicing, it’s smart to inspect the leads every service interval for cracking, swollen boots, green corrosion on terminals, or carbon tracking. Many tech guides suggest replacement roughly every 60,000–100,000 km or 5–7 years, sooner if the vehicle tows, spends time off-road, or runs hot under-bonnet. When replacing, choose quality silicone-jacketed, resistor-type leads that match the engine (4G54 or 6G72) and route them exactly as per the separators and clips—good lead routing prevents crossfire. A dab of dielectric grease inside each boot helps sealing and future removal. Always pull on the boot, not the cable, and seat the boots with a firm click on both the plug and the distributor cap.

It’s also worth pairing new leads with fresh spark plugs (gapped to spec) and a sound distributor cap and rotor. If chasing a misfire, measure lead resistance with a multimeter, excessively high resistance or an open circuit means the lead’s done. Keep the bay clean, avoid soaking the leads with degreaser, and the Pajero will repay the care with easier starts and smoother touring across Aussie and Kiwi roads.

• Inspect leads every service, replace at 60,000–100,000 km or 5–7 years.
• Use correct engine-specific sets and maintain factory lead routing.
• Combine with fresh plugs and check the cap/rotor for best results.

How often should ignition leads be replaced on a 1991 Pajero?

Most owners will be well served changing them about every 60,000–100,000 km or 5–7 years. High heat, off-road use, or towing can shorten their life, so inspect at each service and replace sooner if cracking, arcing, or misfire symptoms show up.

When in doubt, swapping in a known-good set is a quick way to confirm a lead-related misfire.

What are the common signs the leads need attention?

Rough idle, hesitation under load, increased fuel use, or a check engine light for random misfire (on later markets) are common. You might also hear a ticking at night or see tiny blue arcs if the insulation is breaking down.

Pulling a suspect lead may reveal green corrosion or a burned terminal—both are clear replacement cues.

Can they be changed at home, and any tips?

Yes—do one lead at a time to avoid mixing up the firing order. Push each boot until it clicks on the plug and distributor, use a smear of dielectric grease, and clip the leads into the factory separators to prevent crossfire.

If the cap and rotor are worn, replace them together with the leads for a tidy ignition refresh.