Caterpillar Fuel Injectors: CAT Diesel & Electronic Unit Injectors for C-Series and 3-Series Engines

Caterpillar Fuel Injection Pumps by Engine Family

CAT injection pumps are engine-model specific, with pump type, delivery specification, and timing advance characteristics that differ across engine families and in many cases across build variants within the same engine series. Use the engine family below that matches your machine to confirm the correct pump for your application.

CAT 3306 Injection Pumps

The Caterpillar 3306 is one of the most extensively deployed mechanical diesel engines Caterpillar has ever produced, powering decades of excavators, motor graders, articulated trucks, and industrial equipment across construction, mining, and agricultural applications worldwide. It remains in active service across high-hours fleets in East Africa and globally, and the Cat 3306 injection pump continues to be one of the highest-frequency service items in the CAT 3-series catalogue. Our 3306 range covers:

• Cat 3306 injection pump for all standard 3306 engine configurations
• Caterpillar 3306 injection pump variants cross-referenced to engine serial number and build specification
• Caterpillar 3306 fuel injection pump units catalogued to the correct OEM part reference for confirmed fitment
• 3306 injection pump supply as individual replacement units for direct-swap maintenance and as part of broader fuel system overhauls

The 3306 was produced across a long build history with multiple injection pump configurations at different production stages. Imara Engineering confirms your engine's specific pump variant from the serial number before dispatch to ensure the correct unit reaches your workshop.

AT 3406 and 3406B Injection Pumps

The Caterpillar 3406 and its 3406B variant are high-displacement, high-torque inline six-cylinder engines that powered some of the most capable machines in Caterpillar's lineup, from large excavators and off-highway trucks to marine and industrial applications. The 3406B in particular remains widely operated in active fleets, and its injection pump is a regular service item for maintenance teams managing high-hour equipment. Our 3406 and 3406B range covers:

• Cat 3406 injection pump for all standard 3406 engine configurations
• Cat 3406 B injection pump for the 3406B variant, the most commonly serviced pump in this engine family
• 3406b fuel injection pump and cat 3406b fuel injection pump variants cross-referenced to the correct build specification for this engine series
• 3406b injection pump and 3406 injection pump units catalogued to OEM part numbers for confirmed fitment
• Cat 3412 injection pump for the V12 configuration of the 3406-architecture engine used in the highest-output CAT equipment applications

The 3406B produced across different build years can be fitted with different injection pump variants. Correct identification from your engine serial number is essential before ordering. Our parts team confirms the exact pump before your order is placed.

CAT 3208 Injection Pumps

The Caterpillar 3208 is a compact V8 diesel engine with a long service history across marine vessels, generators, medium excavators, and trucks. Despite the age of the platform, the 3208 continues to operate in active fleets and requires quality injection pump replacements for both scheduled maintenance and unplanned repairs. Our 3208 range includes:

• Cat 3208 injection pump for all standard 3208 engine configurations
• Caterpillar 3208 injection pump units cross-referenced to OEM part references for confirmed fitment
• Individual pump replacement for single-pump faults and complete pump supply for engine overhauls requiring a full fuel system refresh
• The 3208 uses a specific pump configuration distinct from the inline 3306 and 3406 families. Imara Engineering stocks the correct 3208-specification pump and confirms fitment from your engine serial number before dispatch.

CAT 3126, 3116, 3304, and 3204 Injection Pumps

Caterpillar's smaller displacement 3-series engine families power a range of compact and medium equipment across construction, industrial, and agricultural applications. Each has specific injection pump requirements that differ from the larger 3306 and 3406 families. Our range for these engine families covers:

• Cat 3126 injection pump for the electronically managed 3126 engine in its mechanical fuel injection pump configurations
• Cat 3116 injection pump for the 3116 inline six-cylinder used in medium excavators and light construction equipment
• Cat 3304 injection pump and Caterpillar 3304 injection pump for the smaller displacement 3304 four-cylinder engine
• Cat 3204 injection pump for the compact 3204 engine used in the lightest CAT construction equipment applications

For operators uncertain of which engine model their compact CAT machine is fitted with, the engine data plate and serial number will confirm the model code.

CAT C7 Injection Pump

The Caterpillar C7 is a mid-range electronically controlled engine bridging the C-series and the legacy 3-series in CAT's equipment lineup. The cat c7 injection pump serves the mechanical fuel supply function in C7 configurations that rely on a separate high-pressure pump rather than the full electronic unit injector arrangement of the larger C-series engines. Our C7 range includes:

• Cat C7 injection pump units for applicable C7 engine configurations requiring mechanical pump replacement
• Cat fuel injection pump cross-reference to OEM part numbers for the C7 application
• 7e5888 injection pump is one of the most referenced OEM part numbers in the CAT injection pump catalogue, applicable to specific 3-series engine configurations

CAT 3-Series Injection Pump Types: What Your Engine Uses

Caterpillar's 3-series mechanical engine families were fitted with several distinct injection pump configurations across their production history. Understanding which system your engine uses ensures you order the correct pump type without risk of a non-compatible unit reaching your workshop.

Bosch Inline Pumps. Many CAT 3306 and 3406 engines were fitted with Bosch inline injection pumps multi-element plunger pumps where each cylinder has a dedicated pump element delivering high-pressure fuel independently. These are robust, well-understood pumps with strong aftermarket support and are a common service item on high-hours 3306 and 3406 powered equipment.

CAT-Specific Rotary and Unit Pumps Certain 3-series engine variants — including the 3208 and some 3116 applications — used CAT-specific rotary pump designs or individual unit pump configurations rather than Bosch inline units. These require pump identification from the engine serial number before ordering, as they are not interchangeable with the Bosch inline variants on the same engine family.

Mechanical Governor Variants: CAT 3-series pumps were produced with both mechanical governor and hydraulic governor configurations across different build years and equipment applications. The governor type affects delivery characteristics and is an important fitment parameter when ordering a replacement pump. Imara Engineering confirms the correct governor configuration from your engine serial number as part of the fitment check before dispatch.

Warning Signs Your CAT Injection Pump Needs Replacing

CAT 3-series injection pumps are durable under correct maintenance, but high operating hours and fuel quality issues will eventually affect pump performance. Watch for these symptoms on your Caterpillar machine:

1. Hard starting or failure to start — a cat injection pump losing pressure calibration cannot build the fuel pressure required to fire the injectors at cranking speed, particularly on cold starts
2. Black or grey smoke under load — pump delivery volume drift causing overfuelling and incomplete combustion, producing visible exhaust smoke under operating load
3. Loss of power and sluggish throttle response — under-delivery at the pump, reducing the fuel volume reaching one or more cylinders below the level required for rated output
4. Rough idle and engine hunting — pump delivery imbalance across cylinders, causing uneven combustion at low RPM, most noticeable at idle and light load
5. Fuel contamination in engine oil — internal pump seal failure, allowing diesel to bypass into the crankcase, which requires immediate pump replacement to prevent engine oil dilution damage
6. Excessive fuel consumption without load change — pump calibration drift causing excess delivery per cycle without a corresponding increase in power output

More than one of these symptoms occurring together on a CAT machine is a strong indicator that the caterpillar fuel injection pump is the primary fault. Addressing it before the pump fails prevents secondary injector damage and avoids a more costly full fuel system repair.

Why Source Your CAT Injection Pumps from Imara Engineering

1. OEM-specification pumps across every CAT 3-series engine: From the Caterpillar 3306 fuel injection pump to the 3406B, 3208, 3126, and 3116, every CAT fuel pump we stock is catalogued to the correct OEM part reference and supplied to the original pressure calibration and delivery specification for that engine model.
2. Serial number confirmed fitment before dispatch: CAT 3-series pump variants differ across build years and equipment applications within the same engine family. Imara Engineering confirms the exact caterpillar injection pump from your engine serial number, not just the model code, to ensure the correct unit is dispatched every time.
3. Coverage for the full CAT 3-series engine range: Our catalogue covers the 3306, 3406, 3406B, 3208, 3126, 3116, 3304, 3204, 3412, and C7 engine families under a single collection so regardless of which CAT engine your fleet runs, the correct CAT injection pump is available from one supplier.
4. Fast dispatch, worldwide shipping: Imara Engineering supplies CAT equipment operators, workshop teams, and fleet maintenance managers across East Africa and internationally. Orders are processed fast from our stocked warehouse and shipped worldwide, so your machine returns to operation without extended downtime.
5. Complete CAT fuel system coverage in one order: If your injection pump fault has caused downstream injector damage, Imara Engineering stocks Caterpillar fuel injectors in a separate collection that can be combined into a single order. Fuel lift pumps, fuel lines, and shutoff solenoids for CAT equipment are also available, so the complete fuel system repair is one consolidated order from one supplier.