Mitsubishi Pajero Sport: 4D56 common-rail injector failure - black smoke, knock and misfires (Challenger PB/PC)

The Challenger's 2.5 4D56 common-rail diesel relies on precise Denso injectors that wear with age and poor fuel, causing black smoke, diesel knock, misfires (P0201-series codes) and worsening economy. Failed injectors that dribble fuel can wash cylinder bores and dilute the oil, so it is not a fault to sit on. The 4D56 also runs a timing belt (not a chain) - an overdue belt on a neglected example is an engine-destroying risk and a service history question you must ask.

• Black smoke under acceleration
• Loud diesel knock, uneven idle
• Misfire codes / check engine light
• Rising oil level or diesel smell in the oil

1. 1

   Cold-start it yourself; listen for knock and watch the exhaust under a hard test-drive acceleration.

2. 2

   Pull the dipstick and smell for diesel in the oil.

3. 3

   Ask when the timing belt was last done - if unknown, budget for it immediately.

Parts involved: Fuel rail, Fuel injector.

$1,200 to $4,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the injectors been replaced or tested, and when?”
• “When was the timing belt last changed?”
• “Any misfire or injector fault codes in the past?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.