Caterpillar 1167150 Unit Injector – The Number That Unlocks 3126 Performance

In the Caterpillar parts ecosystem, some numbers stand alone. Others sit at the center of a web of cross-references, interchange numbers, and alternative listings. The Caterpillar 1167150 is firmly in the second category.

This isn't just a part number. It's a node in a network - a single identifier that connects to at least six other part numbers, each pointing to the same precision-engineered fuel injector. For operators running Caterpillar 3126 engines, the 1167150 is the number that unlocks access to one of the most critical components in the fuel system: the unit injector that meters and delivers fuel with the precision these engines demand.

 

The 1167150 belongs to Caterpillar's HEUI (Hydraulically actuated Electronically controlled Unit Injector) family - a system that diverges fundamentally from both common rail and mechanical injection architectures.

What makes HEUI different:

Oil-actuated, fuel-pressurized - engine oil, pressurized by a high-pressure oil pump, is used to actuate the injector plunger, which then pressurizes the fuel for injection

Electronic control - the ECU determines injection timing and duration, while the hydraulic system provides the muscle

Independent operation - each cylinder has its own injector, allowing for cylinder-specific fuel delivery optimization

The 1167150 is the injector that sits at the heart of this system for Caterpillar 3126 engines - a platform that powers everything from medium-duty trucks to construction equipment, agricultural machinery to marine applications.

 

The 1167150 is part of an interchange network that gives parts buyers options:

Part Number	Relationship
1167150	Primary part number
116-7150	Dashed format variant
0R4972	Caterpillar remanufactured number
FS0R4972	Remanufactured variant
1601696	Alternate number
160-1696	Dashed format variant
1193346	Alternate number
119-3346	Dashed format variant

Why this network matters:

Sourcing flexibility - if one number is out of stock, another may be available

Cross-brand compatibility - aftermarket manufacturers often use different numbering systems

Price comparison - the same injector may be listed under different numbers at different price points

Inventory optimization - distributors can stock one injector and serve customers searching by any of these numbers

The 1167150 sits at the center of this network - a single point of reference that connects buyers to the injector they need, regardless of which number they start with.

 

The 1167150 is engineered for the Caterpillar 3126 engine - a 7.2-liter inline-six diesel that has powered countless vehicles and machines since its introduction in the 1990s.

Primary applications include:

Medium-duty trucks - Freightliner, International, and other chassis manufacturers

Construction equipment - excavators, loaders, and graders

Agricultural machinery - tractors and harvesters

Marine applications - workboats and auxiliary power

Industrial power units - generators and pumps

Production years for vehicles using this injector span approximately 2001 through 2005.

Physical specifications:

Product type: Unit injector (HEUI)

Condition: Available as new, remanufactured, or aftermarket replacement

Packaging: TIP 4 configuration (approximately 13×22×12 cm)

 

For the 1167150, remanufacturing is not just an option - it's a Caterpillar-backed standard.

What Cat Reman means:

Same-as-new warranty - Caterpillar provides a warranty equivalent to new parts on all remanufactured fuel injectors

Rigorous testing - remanufactured injectors pass the exact same testing points as new Cat injectors

Off-the-shelf availability - no waiting for a returned unit to be repaired

Like-new performance - restored to OEM specifications using genuine Cat components

The remanufacturing process involves complete disassembly, cleaning, inspection, replacement of worn components, and 100% flow testing of nozzles. Each injector is assigned a unique calibration code in accordance with OE specification, and the ECU must be updated with this code for proper performance.

Why choose remanufactured:

Cost-effective compared to new

Environmentally responsible - reduces waste and conserves resources

Backed by Caterpillar's quality assurance

Same performance as new

 

HEUI injector replacement requires systematic attention:

Disconnect battery power before servicing - prevents potential ECU issues

Relieve high-pressure oil system pressure before any work begins

Remove the valve cover to access the injectors

Use the correct extraction tool - HEUI injectors require specialized removal tools

Clean the injector bore thoroughly before inserting the new injector

Replace all O-rings and seals - these are single-use components

Critical note: After installation, the injector must be properly calibrated using the appropriate diagnostic tool. The ECU needs the correct calibration code to make the relevant adjustments. Skipping coding can lead to rough idle, fault codes, and increased fuel consumption.

 

The 3126 is no longer in production. But the trucks, excavators, loaders, and generators that carry it are still earning revenue. The 1167150 directly influences:

Fuel economy - precise metering means every drop counts

Power output - optimized atomization supports complete combustion

Emissions compliance - accurate delivery reduces particulates and NOx

Service longevity - Caterpillar's remanufacturing process restores like-new performance

 

Q1: What engine does the 1167150 fit?
The 1167150 is engineered for the Caterpillar 3126 engine - a 7.2-liter inline-six diesel used in medium-duty trucks, construction equipment, agricultural machinery, and marine applications. Production years span approximately 2001 through 2005.

Q2: What's the difference between 1167150 and 0R4972?
They're the same injector. 1167150 is the standard part number; 0R4972 is the Caterpillar remanufactured number. Both refer to the identical HEUI unit injector for the 3126 engine. The 0R4972 has been remanufactured by Caterpillar to OEM specifications.

Q3: Can I use other interchange numbers instead of 1167150?
Yes - the 1167150 is part of an interchange network that includes 116-7150, 0R4972, FS0R4972, 1601696, 160-1696, 1193346, and 119-3346. All these numbers point to the same injector, giving you flexibility in sourcing.

Q4: What are the warning signs that my injector is failing?
Common symptoms include loss of power under load, excessive black or white smoke at idle or acceleration, rough idle or misfires, increased fuel consumption, hard starting or extended cranking times, and fuel leaks around the injector.

Q5: Is a remanufactured injector as good as new?
Yes - Cat Reman injectors are remanufactured to like-new performance and pass the exact same testing points as new Cat injectors. They come with a same-as-new warranty and are available off the shelf from dealers. The key is ensuring the injector is properly calibrated after installation.

Q6: Is coding required after installation?
Yes. Each injector has unique calibration characteristics, and the ECU must be updated with the correct injector code. If coding is skipped, the engine may show performance instability, rough idle, or fault codes. Always use the appropriate diagnostic tool to enter the calibration data.