12634491
HITACHI 12634491 High Pressure Fuel Pump Chevy Camaro Buick Regal Cadillac ATS CTS 2.0T LTG HPP0008
12658339, 12651170, HPP0008, HM10014, GDP104, 12641847--150 barVehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Cadillac ATS / ATS-L 2.0T | GM 2.0L Ecotec Turbo SIDI (LTG / LSY Tripower / LHU) | 2013-2019 |
| Buick Regal GS / Regal 2.0T | GM 2.0L Ecotec Turbo SIDI (LTG / LSY Tripower / LHU) | 2014-2020 |
| Buick Envision 28T AWD | GM 2.0L Ecotec Turbo SIDI (LTG / LSY Tripower / LHU) | 2015-2020 |
| Chevrolet Camaro 2.0T | GM 2.0L Ecotec Turbo SIDI (LTG / LSY Tripower / LHU) | 2016-2020 |
Technical Specifications
| Specification | Value |
|---|---|
| Part Number / SKU | 12634491 |
| Manufacturer Brand | HITACHI |
| Component Type | Mechanical High Pressure Fuel Pump (HPFP) |
| Engine Application | GM 2.0L Ecotec Turbo SIDI DOHC (LTG) |
| Operating PressureCore Spec | |
| Mounting Torque (Flange / Bracket) | 13 N-m (115 lb-in) |
| Fuel Line / Rail Torque | 30 N-m (22 lb-ft) |
| Primary Diagnostic Fault Codes | P0087, P0088, P0089, P0171 |
Matched High-Pressure Fuel Pump (Fuel Circuit Assembly)
Operates on the same high-pressure rail circuit. When troubleshooting low rail pressure (DTC P0087), verify pump volumetric delivery before replacing injectors.
Installation Tips
- Depressurize Fuel System: Pull fuel pump fuse or disconnect LPFP harness. Crank engine 5-8 seconds until it stalls to drop residual rail pressure below 5 bar.
- Clean Surrounding Cavity: Blow compressed air around cylinder head bore or pump flange cavity to prevent dirt ingress into the fuel rail.
- Lubricate & Fit Seals: Inspect Teflon combustion seals or O-rings. Coat lightly with clean motor oil (do not use grease) to avoid tearing during insertion.
- Torque to Factory Specification: Hand-thread bolts evenly. Tighten mounting fasteners to 13 N-m (115 lb-in), and torque fuel line fittings to 30 N-m (22 lb-ft).
- Prime & Leak Check: Cycle ignition to RUN position 3 times (5 seconds each) to build low-side pressure. Inspect fittings for leaks before starting engine.
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.