DENSO
16611-AA720
View Specs
SolenoidSubaru Multi-Point Turbo Electronic Fuel Injection (MPI 43.5-psi High-Flow System)Euro 2545
DENSO 16611-AA720 Top-Feed Fuel Injector 565cc Subaru Impreza WRX STI Forester XT Legacy GT 2.5L Turbo EJ257 EJ255
OE REFERENCE
16611-AA72A, FJ942, 195500-4430CONTROL VALVE
12-Hole High-Flow Micro-Atomization DirectorNOZZLE
-RAIL PRESSURE
3.0 barEMISSIONTier 2 Bin 5 / Euro 4 / Euro 5 / LEV II
WARRANTY12 Months
02
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Subaru WRX STI GRB/GVB/VAB | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2007-2021 |
| Subaru Impreza WRX / Forester XT | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2008-2014 |
| Subaru Legacy GT / Outback XT | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2008-2012 |
03
Technical Specifications
| Specification | Value |
|---|---|
| System Type | Subaru High-Flow Multi-Point Turbo Electronic Fuel Injection |
| Operating Fuel Pressure | 3.0 bar (43.5 psi / 300 kPa nominal regulated differential pressure) |
| Static Fuel Flow Rate | 565 cc/min @ 3.0 bar (53.8 lb/hr) genuine blue injector body |
| Coil Resistance | 11.5 - 12.5 Ohms @ 20°C (High-Impedance Saturated Solenoid) |
| Spray Geometry | 12-Hole High-Flow Dual-Cone Atomization Director |
| Fuel Rail Securing Fasteners Torque | 19 N·m (14 lb-ft) fuel rail mounting bolts |
| Fuel Rail Protector Shield Bolts | 7.5 N·m (66 in-lb) sheet metal safety shields |
| Seals Architecture | Upper Viton Fluorocarbon O-Ring & Lower Intake Manifold Seal Ring |
| Manufacturer | Denso Corporation (Tier-1 OEM for Subaru Corporation) |
| Denso Production Reference | 195500-4430 / 16611-AA720 |
| Operating PressureCore Spec |
04
Installation Tips
Tips & Warnings:
- Mandatory lower seal ring renewal: Never reuse hardened lower manifold rubber seal rings; boost pressure from the turbo will blow past compromised lower seals, causing unmetered boost leaks and violent lean backfires.
- Prevent cylinder 4 fueling starvation: Cylinder #4 runs hottest on EJ257 engines; ensure injector filter screens are immaculately clean or flow-matched to prevent lean detonation and catastrophic ringland failure.
- Never use petroleum jelly or silicone spray: Lubricate O-rings strictly with clean engine oil or clean assembly lubricant to protect O-ring integrity and lambda sensors.
- Double-check fuel rail safety shields: Reinstall all stamped steel safety shields securely; they protect pressurized fuel rails during side impacts.
05
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
P0087Critical
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
P0201 - P0208High
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.
P0300 / P0301+High
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
P0088High
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
WORKSHOP PROTOCOLS
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.
Workshop Diagnostic Protocol
Read Technical ProtocolCommon Rail Injector Back-Leak Testing Guide
COMMON RAIL DIESEL WORKSHOP SOP
Read Technical ProtocolStuck Injector Removal & Carbon Cleaning SOP | FuelPartsDB
ASSEMBLY & INSTALLATION PROTOCOL
Read Technical Protocol