Buy Injection Pump Online

Also known as: Injection Pump, Fuel Injection Pump

OEM & aftermarket diesel injection pump from top brands — compare prices, check fitment, order with free delivery

Best price from 7+ suppliers

Shop 636 diesel injection pump from 9 trusted brands including BOSCH, DIESEL REMAN, AKUSAN. Compare prices, check vehicle compatibility, and get free delivery on orders over £99.

Diesel Injection Pump for the top car models

Alfa Romeo186

Diesel Injection Pump buying guide — what to know before you buy

The diesel injection pump pressurises fuel to the level required for fine atomisation in the cylinder. Older vehicles use rotary or in-line distributor pumps; common-rail systems use a high-pressure pump feeding a shared rail. Pump failure causes poor running, hard starting, and in severe cases catastrophic engine damage.

When to replace

Diesel pumps are precision components and should be diagnosed before replacement. Many faults are caused by upstream issues such as contaminated fuel or a blocked filter.

Hard starting when warm or cold
Erratic idle or stalling at low rpm
Loss of power and excessive smoke under load
Diesel fuel leak from the pump shaft seal or supply union
Fault codes referencing rail pressure or pump regulation

What to look for when buying

Modern injection pumps are matched to the engine ECU and fuel system. Reconditioning is often more cost-effective than buying new.

Match the part number to the engine code, not just vehicle model
Confirm the pump type — Bosch CP1, CP3, CP4, Delphi DP200, Siemens VDO
Bench testing data should be supplied with reconditioned units
CP4 pumps require strict fuel filtration to avoid metal-on-metal damage
Some pumps require coding to the ECU after fitment

Common failure modes

Pump damage usually starts with fuel contamination and progresses rapidly.

Water-contaminated fuel rusts the internal plungers and causes pressure loss
Particulate contamination scores the pump rotor and produces metal swarf
Shaft seal failure leaks diesel into the timing belt area or sump
Solenoid or pressure regulator failure causes erratic rail pressure
Cam ring wear in CP4 pumps releases debris into the entire fuel system

Related parts to check together

Pump failure often takes the rest of the fuel system with it. Replace contamination paths before fitting a new pump.

Fuel injectors — replace or clean to match the new pump's tolerances
Fuel filter — fit a new filter and pre-filter to protect the pump
High-pressure fuel lines — replace if they have been opened or corroded
Fuel tank — inspect for water and debris if fuel contamination caused the failure

Frequently Asked Questions

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Can a diesel injection pump be repaired?

Yes, specialist diesel workshops rebuild Bosch and Delphi pumps with new plungers, seals, and electronic components. Reconditioned pumps are often half the cost of new and carry a warranty.

Why is my diesel injection pump leaking fuel?

The most common cause is a worn shaft seal. On some pumps this can be replaced separately; on others the leak indicates internal wear and a full reconditioning is needed.

What damage does contaminated fuel cause to the pump?

Water causes corrosion and seizure. Particulates score the precision-machined plungers and release metal swarf that travels to the injectors, often destroying the entire fuel system.