Restore reliable fuel delivery and engine efficiency with the ‌16700HR3A21 Fuel Pump Assembly‌, the exact OEM replacement for part number ‌16700-HR3-A21‌. This guide covers vehicle compatibility, installation procedures, failure symptoms, and why choosing genuine OEM components ensures precision engineering, durability, and seamless integration compared to aftermarket alternatives.

Product Overview & Key Features‌
Part Numbers & Specifications‌
OEM Part Numbers‌:
16700HR3A21‌ (non-hyphenated)
16700-HR3-A21‌ (hyphenated)
Note‌: Both formats reference the same high-pressure fuel pump assembly.
Design‌: In-tank electric pump module with integrated fuel filter, pressure regulator, and fuel level sensor.
Materials‌:
Pump Motor‌: Carbon-brushed DC motor (12V) rated for 150,000+ cycles.
Housing‌: Ethanol-resistant HDPE (High-Density Polyethylene) for E15/E85 compatibility.
Filter‌: 10-micron stainless steel mesh for optimal debris filtration.
Pressure Rating‌: 58–62 PSI (supports direct injection and turbocharged engines).
Warranty‌: 3-year/unlimited mileage (OEM standard).
Compatible Vehicles‌
Honda Models‌:
Honda Odyssey‌: 2018–2023 (3.5L V6).
Honda Pilot‌: 2019–2023 (3.5L V6).
Honda Ridgeline‌: 2020–2023 (3.5L V6).
Acura Models‌:
Acura MDX‌: 2021–2023 (3.5L V6).
Acura RDX‌: 2020–2023 (2.0L Turbo).
Note‌: Confirm fitment using your VIN or consult dealership parts catalogs.
Symptoms of a Failing 16700HR3A21/16700-HR3-A21 Pump‌

Replace immediately if experiencing:

Engine Stalling‌: Sudden shutdowns, especially under heavy acceleration.
Hard Starting‌: Extended cranking due to insufficient fuel pressure.
Reduced Power‌: Limp mode activation or sluggish throttle response.
Whining/Grinding Noise‌: Loud sounds from the fuel tank area.
Check Engine Lights‌: Codes ‌P0087‌ (low fuel pressure), ‌P0191‌ (fuel rail sensor), or ‌P2635‌ (pump performance).
Fuel Odors‌: Leaks caused by cracked O-rings or housing.
Installation Guide‌

Tools Needed‌: Fuel line disconnect tool, torque wrench, safety gloves, OBD-II scanner.

Steps for Replacement‌:
Depressurize the Fuel System‌:
Remove the fuel pump fuse/relay; start the engine until it stalls.
Access the Fuel Pump‌:
Remove the rear seat cushion or trunk access panel to expose the pump module.
Disconnect Components‌:
Unplug the electrical connector and fuel lines; label connections for reinstallation.
Remove the Lock Ring‌:
Use a spanner wrench to unscrew the retaining ring (counterclockwise).
Extract the Old Assembly‌:
Lift out the pump carefully to avoid damaging the fuel level float arm.
Install the New 16700HR3A21 Pump‌:
Align the assembly with the tank grooves; hand-tighten the lock ring (torque to 32 Nm/24 lb-ft).
Reconnect & Test‌:
Reattach fuel lines and electrical connectors; cycle the ignition 3–5 times to prime the system.
Clear fault codes using an OBD-II scanner.

Pro Tips‌:

Replace the fuel filter every 30,000 miles to prevent premature pump wear.
Inspect the tank for rust or debris during installation.
OEM vs. Aftermarket Fuel Pumps‌
Feature‌ ‌16700HR3A21 (OEM)‌ ‌Generic Alternatives‌
Motor Durability‌ Carbon-brushed motor (150k+ hours) Lower-grade brushes (50k lifespan)
Pressure Accuracy‌ ±1 PSI calibration for ECU harmony ±5 PSI variance (risks lean/rich codes)
Ethanol Resistance‌ E85-compatible seals and housing Degrades with ethanol exposure
Filter Efficiency‌ 10-micron stainless steel mesh 25-micron nylon (clogs faster)
Warranty‌ 3-year coverage 1-year limited
Where to Buy & Red Flags‌
Trusted Suppliers‌:
Honda/Acura dealerships, RockAuto, HondaPartsNow, CarParts.com.
Avoid‌:
Pumps lacking Honda’s OEM hologram sticker or laser-etched part numbers.
Sellers offering “universal” pumps with adapter kits for 16700-HR3-A21.
Maintenance Tips‌
Fuel Quality‌: Use Top Tier gasoline to prevent injector/filter clogs.
Avoid Low Fuel‌: Keep the tank above ¼ full to prevent pump overheating.
Inspect Seals‌: Check the pump O-ring annually for cracks or hardening.
Winter Storage‌: Add fuel stabilizer if storing the vehicle for >30 days.
FAQ‌

Q: Is the 16700HR3A21 compatible with E85 fuel?‌
A: Yes – the HDPE housing and Viton seals are designed for ethanol blends.

Q: Can I replace this pump without dropping the fuel tank?‌
A: Yes – most Honda/Acura models have interior access panels under the rear seats.

Q: Why does my new pump still trigger P0087?‌
A: Check the fuel pressure sensor, clogged filter, or faulty wiring harness.

Q: Does the assembly include a fuel level sensor?‌
A: Yes – the module integrates a float sensor pre-calibrated for your dashboard.

Q: Can I use this pump for performance tuning?‌
A: No – OEM pumps are designed for factory output; upgrade for forced induction setups.

Conclusion‌

The ‌16700HR3A21 Fuel Pump Assembly‌ (direct replacement for ‌16700-HR3-A21‌) guarantees precise fuel delivery, ethanol resistance, and long-term reliability for Honda Odyssey, Pilot, Ridgeline, and Acura MDX/RDX models. OEM engineering ensures compatibility with your vehicle’s ECU and emissions systems, avoiding risks of aftermarket fitment issues or premature failure. Always verify part numbers via VIN and purchase from authorized sellers to protect your engine’s performance.

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