Mechanical & inline diesel pump repair
We diagnose, rebuild and calibrate mechanical and inline fuel injection pumps — including in-line multi-cylinder pumps, single-plunger pumps and older P/A/Z-type units — found on trucks, buses, generators, agricultural and marine diesel engines.
Built for engines that still run on mechanical injection
Mechanical and inline diesel pumps remain in service across a large share of Doha's commercial trucks, buses, generators, marine engines and agricultural equipment. Unlike common rail systems, these pumps rely on precisely timed plungers and mechanical governors, so wear in the barrel, plunger, delivery valve or governor linkage shows up directly as rough running, smoke or power loss.
Our workshop strips the pump down to individual components, inspects plunger and barrel wear, replaces delivery valves, seals and bearings as needed, then rebuilds and sets the pump on a dedicated calibration test bench — matching delivery volume and injection timing across every cylinder to the manufacturer's specification before it goes back on the engine.
Key Service Capabilities:
- In-line multi-cylinder pump (P, A, Z-type) rebuild and calibration
- Single-element and single-plunger pump repair
- Governor and timing device overhaul
- Plunger, barrel and delivery valve replacement
- Full flow and timing calibration on test bench
Mechanical pumps we service:
P, A and Z-type in-line pumps with one plunger per cylinder — common on medium and heavy trucks, buses and gensets.
Compact single-element pumps used on smaller diesel engines, pumps sets and light machinery.
Centrifugal and pneumatic governor overhaul to restore stable idle and correct engine speed control.
What a failing mechanical or inline pump looks like
Full symptom guides live in Resources — here's the quick version.
Hard starting or rough idle
Worn plungers or delivery valves cause uneven fuel delivery across cylinders.
Loss of power under load
Reduced delivery volume from internal wear, often worse when towing or under heavy load.
Black or excessive smoke
Incorrect timing or over-fuelling on one or more cylinders, usually from governor or timing wear.
From diagnosis to calibrated pump, start to finish
Strip & inspect
Pump is fully stripped and every component checked against wear tolerances.
Rebuild
Worn plungers, barrels, delivery valves and seals replaced with OEM-standard parts.
Bench calibration
Delivery volume and timing set and matched across all cylinders on the test bench.
Fit & road test
Pump refitted and engine performance verified before handover.