BL3Z-9350-A
BOSCH BL3Z-9350-A High Pressure Fuel Pump Ford F-150 3.5 EcoBoost
BL3Z-9350-A, DL3Z-9350-A, HL3Z-9350-A, GL3Z-9350-A, 0261520143Integrated Solenoid Quantity Control Valve-150 barProduct Overview
The Bosch BL3Z-9350-A (Ford OE DL3Z-9350-A / HL3Z-9350-A / Bosch 0261520143) is the factory original equipment high-pressure mechanical fuel pump for Ford 3.5L EcoBoost Twin-Turbo V6 engines. Driven by the driver-side (left bank) intake camshaft auxiliary tri-lobe via a tappet follower bucket, this robust pump pressurizes low-pressure tank fuel up to 150 bar (2175 psi). Standard equipment on the Ford F-150, Expedition, Lincoln Navigator, and Transit commercial vans, it supplies the high-demand direct-injection fuel rail during heavy towing and boost. Symptoms of pump wear include heavy bucking under load, loss of power when towing, extended morning start times, and diagnostic codes P0087 and P0172.
TAPPET PUNCH-THROUGH & OIL CONTAMINATION WARNING: On high-mileage Ford 3.5L EcoBoost engines, the flat tappet follower bucket (Ford OE 7T4Z-6C535-AA) wears through its hardened face if engine oil changes are neglected. Once worn through, the hardened pump plunger grinds directly into the intake camshaft lobe, sending steel shavings into VCT solenoids and phasers. Furthermore, leaking internal seals dump fuel into the crankcase, causing gasoline-diluted engine oil and P0172 rich codes.
Vehicle & Engine Fitment
Technical Specifications
| Specification | Value |
|---|---|
| Pump Generation | Bosch HDP-5 High Pressure Radial Fuel Pump |
| Operating Rail PressureCore Spec | |
| Cam Drive Type | Left Bank Intake Camshaft Tri-Lobe via Flat Tappet |
| Tappet Follower Part Number | Ford OE 7T4Z-6C535-AA (Inspect for wear cratering) |
| Integrated Component | Electric Fuel Volume Regulator Solenoid Valve |
| Flange Fastener Torque | 10 N·m (Torx M6, alternating two-step torque) |
| High Pressure Output Line Nut Torque | 28 N·m (Counter-hold body adapter) |
| Tightening Torque | 28 N·m |
| Hold Down Torque | 10 N·m |
| Default Safety Pressure Mode | Mechanical bypass ~4.5-5.5 bar low pressure feed |
| Operating PressureCore Spec |
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
Tools needed: 17mm line wrench and open-end backup wrench, Torque wrench calibrated for 10-28 N·m, 8mm and 10mm sockets with extensions, Clean engine oil for pump O-ring and tappet lubrication, Lint-free shop towels and protective glasses
- Disconnect the negative battery cable; pull the fuel pump relay and crank the engine for 5 seconds to depressurize low-pressure supply lines.
- Wrap clean towels around the high-pressure steel tube nut and slowly crack the 17mm flare nut to vent residual rail pressure.
- Disconnect the electrical connector from the volume regulator solenoid on top of the pump body.
- Remove the quick-connect clip and disconnect the low-pressure fuel supply hose.
- Loosen the two pump mounting bolts half a turn at a time to relieve internal plunger spring pressure evenly.
- Remove the pump from the valve cover bore; extract tappet bucket 7T4Z-6C535-AA and inspect the contact face for dish wear or scoring; replace immediately if dished.
- Clean the cylinder head mounting surface and coat the new Viton O-ring seal with clean motor oil.
- Position the camshaft lobe on its base circle (lowest point of lift).
- Lubricate the tappet bucket with clean oil, place it into the bore, and position the pump onto the housing.
- Thread the mounting bolts finger-tight, then torque alternately in steps to 10 N·m.
- Thread the high-pressure steel tube flare nut by hand; counter-hold the pump body fitting with an open-end wrench and torque flare nut to 28 N·m.
- Reconnect low-pressure hose and electrical harness; cycle ignition key three times to prime fuel system, then inspect for leaks before starting.
- Counter-Holding Body Fitting Requirement: When torquing the 17mm high-pressure line flare nut to 28 N·m, you MUST counter-hold the pump body adapter with an 18mm open-end wrench. Torquing without counter-holding loosens the internal union and creates severe fire hazards.
- Tappet Bucket Inspection Mandate: Never install a new HPFP onto an old, worn tappet bucket. A worn tappet bucket will puncture and destroy both the new pump plunger and the camshaft within 500 miles.
- Mandatory Crankcase Oil Service: If the HPFP is replaced due to an internal seal rupture, you must change the engine oil and filter immediately. Gasoline contamination destroys main bearings and turbocharger thrust bearings under heavy load.
Frequently Asked Questions
What trouble codes indicate a failing high pressure fuel pump on Ford F-150 3.5 EcoBoost?
The most common fault code is P0087 (Fuel Rail/System Pressure - Too Low), causing severe engine hesitation, spark blowout, and limp mode during towing or heavy acceleration. If internal pump seals leak into the valvetrain, P0172 and P0175 (Fuel System Rich) appear from fuel-saturated crankcase fumes.
Why does my Ford F-150 3.5 EcoBoost engine oil smell strongly like gasoline?
On the 3.5L EcoBoost, the HPFP is mounted directly into the driver-side valve cover. When the internal plunger seal fails, raw pressurized gasoline leaks past the shaft directly into the valvetrain oil passages. A rising oil dipstick level and strong fuel odor confirm internal pump failure.
Can a bad HPFP cause extended morning cranking on Ford Expedition or Navigator?
Yes. If the internal one-way check valve in the pump fails, high-pressure rail pressure bleeds down to 0 bar overnight. In the morning, the engine must crank for 5 to 8 seconds while the mechanical pump rebuilds the minimum 35 bar required for direct injection startup.
Say this to the shop: How can the technician confirm HPFP failure before replacing it?
Ask the technician: 'Please use FORScan or IDS to datalog Fuel Rail Pressure Desired versus Actual under full boost in 4th gear. If low-pressure lift pump pressure remains steady at 55 psi while actual rail pressure plummets below 1200 psi, the HPFP is defective without guessing.'
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.
Cross-Reference & Compatibility
Sister parts, same-platform variants, and known incompatibilities.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.