Toyota LC80: 1HZ Injection Pump Governor Weight Wear

The Nippondenso in-line mechanical injection pump governor weights develop flat spots and pivot pin wear with high mileage use. Worn weights fail to regulate fuel delivery accurately at low RPM, causing hunting or surging idle that may clear at higher engine speeds. Excessive black or white smoke on cold start and difficult starting in cold weather are common. A pump rebuild or replacement is typically required beyond 250,000 km on working vehicles.

• Hunting or surging idle speed
• Rough idle that clears above 1500 RPM
• Excessive black smoke on cold start
• Difficult cold starting
• Poor fuel economy at low speeds

1. 1

   Start the engine cold and observe idle quality through warm-up.

2. 2

   Rev to 2000 RPM and release throttle abruptly - watch for hunting as revs return to idle.

3. 3

   Request injection pump service history and check for recent rebuild.

Parts involved: High-pressure fuel pump.

$900 to $2,800 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.

• “Has the injection pump been rebuilt or replaced?”
• “When was the last injection pump service?”
• “Does the idle hunt or surge when fully warmed up?”
• “Has smoke or difficult starting ever been reported?”

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.