Diesel Injection Pump (Distributor Or Inline Pump)

Rotary distributor pumps and inline pumps were common before common rail systems. The pump is driven by the engine and timed to the crankshaft. Mechanical pumps were later fitted with electronic control. Many older pumps can be overhauled by diesel specialists. Timing marks on the pump and engine must match when refitting.

Plungers inside the pump compress fuel and send it through high-pressure pipes to the injectors in firing order.

Incorrect pump timing causes smoke, knocking and hard starting. Contaminated or waxed fuel can damage the precise internal parts.