Mitsubishi Fuel Pump
Mitsubishi Fuel Pump Technology Matrix
Mitsubishi powertrain engineering utilizes three distinct fuel delivery architectures: high-pressure Direct Injection Gasoline (GDI / DI-D), heavy-duty Common Rail Diesel Injection (CRDi), and standard Multi-Port Injection (MPI).
1. Direct Injection & Turbo-Petrol (4B / 4A Series): Cam-Driven HPFP + Low-Pressure In-Tank Lift Pump
This configuration is standard on modern high-efficiency MIVEC (Mitsubishi Innovative Valve timing Electronic Control) platforms.
- Modern MIVEC Direct Injection Engine Families (4B40 1.5T, 4B11/4B12 Smart DI, 4A91 DI):
- Applicable Models: ASX (modern DI variants), Outlander/Airtrek (2.4L / 1.5T platforms), RVR, Eclipse Cross (1.5T DI), and Galant Fortis (4B11 DI variants).
- System Mechanics: These vehicles run a high-pressure dual-stage architecture. A low-pressure electric fuel pump module submerged in the gas tank pushes fuel forward at a standard ~55–65 PSI. Once it reaches the engine cylinder head, a mechanical high-pressure fuel pump (HPFP) driven directly by a lobe on the camshaft compresses that fuel to pressures anywhere between 2,000 and 3,000+ PSI for direct atomization inside the cylinders.
- Maintenance Requirement: The mechanical HPFP plunger relies on consistent engine oil lubrication. Extended oil change intervals lead to additive degradation, resulting in camshaft lobe and pump follower scoring. This wear typically manifests as low fuel pressure diagnostic codes (P0087).
2. Di-D High-Pressure Common Rail Diesel: Engine-Driven Supply Pump + In-Tank Lift Pump
Designed for high-torque applications, off-road performance, and heavy-duty commercial cycles.
- Mitsubishi Clean Diesel Families (4N15, 4M41 Di-D Turbo-Diesel):
- Applicable Models: Pajero (3.2L Di-D) and Montero Sport (2.4L 4N15 platforms).
- System Mechanics: An electric in-tank lift pump draws diesel from the tank through a primary water-separating fuel filter. The fuel then enters a high-load, engine-timed mechanical injection supply pump (Denso HP type) driven by the timing chain. This pump ramps pressures up to a massive 26,000 to 29,000+ PSI inside a shared high-pressure common rail, which feeds the electronic solenoid diesel injectors.
- Maintenance Requirement: Diesel injection systems are highly sensitive to water contamination. To prevent internal seizure and metal shavings from contaminating the fuel system, the primary water separator must be serviced every 10,000 km.
3. Multi-Port Injection (MPI): Single In-Tank Low-Pressure Electric Fuel Pump Module
The fundamental fuel architecture for Mitsubishi’s compact commuters and legacy performance models.
- Traditional Port-Injected Powertrains (3A92, 4A90, 4B11/4B12 MPI, 4G63T Legacy):
- Applicable Models: Mirage (3A92), Lancer Evolution (4G63T / 4B11T), Colt, eK Keicar, and early production years of the ASX, Outlander, and Galant Fortis.
- System Mechanics: This architecture uses an all-in-one electric fuel pump module dropped into the fuel tank via an access panel under the rear seat or trunk floor. This unit houses the DC electric motor, a fine-mesh plastic intake strainer, and a mechanical fuel pressure regulator. It maintains a constant feed pressure of 43 to 52 PSI straight to the fuel rail.
- Operational Note: The electric fuel pump relies on the surrounding fuel for thermal regulation. Operating with a low fuel level can cause the motor to overheat and prematurely wear the internal brushes; refueling before the level drops below 1/4 tank is recommended.
Complete Fleet Fuel Pump Quick Reference Table
|
Vehicle Family |
Primary Engine Layout Found |
Fuel Delivery Architecture Type |
Primary Operating Pressure |
Primary Filter Access |
|
ASX |
4B11 MPI | 4B12 DI MIVEC |
Single In-Tank EFI | Dual Pump (Modern) |
45 PSI Port / 2,500 PSI DI |
Under Rear Seat Bench |
|
Outlander / Airtrek |
4B12 NA | 4B40 1.5T | 4G63T |
Dual Pump (DI Turbo) | Single In-Tank |
60 PSI Lift / 2,900 PSI Rail |
Access Panel Under Bench |
|
Pajero |
4M41 3.2 Di-D | 6G75 V6 |
Dual Pump (Diesel CRDi) | Single EFI |
29,000 PSI Diesel / 50 PSI Petrol |
Rear Cargo Floor Panel |
|
Mirage |
3A92 1.2L 3-Cylinder |
Single In-Tank Electric MPI |
43 – 48 PSI |
Under Rear Seat Base |
|
Evolution |
4G63T (Evo 9) | 4B11T (Evo X) |
Single In-Tank High-Flow EFI |
50 – 58 PSI Port |
Under Rear Seat Bench |
|
Galant Fortis |
4B11 MIVEC | 4B11T Ralliart |
Single In-Tank EFI | High-Flow MPI |
45 – 52 PSI |
Under Rear Seat Bench |
|
Montero Sport |
4N15 2.4L Di-D Clean Diesel |
Dual Pump (In-Tank + Mechanical CRDi) |
55 PSI Lift / 26,000 PSI High |
Engine Bay (Spin-on) |
|
Eclipse |
4B40 1.5L MIVEC Turbo |
Dual Pump (In-Tank + Cam Mechanical) |
60 PSI Lift / 2,900 PSI Rail |
Under Rear Seat Bench |
|
eK |
3B20 / 3G83 660cc Keicar |
Single In-Tank Electric MPI |
40 – 45 PSI |
Under Rear Floor Mat |
|
Colt |
4A90 1.3L / 4G15 Port |
Single In-Tank Electric MPI |
43 – 48 PSI |
In-Tank Assembly |
|
RVR |
4B10 / 4B11 MIVEC |
Single In-Tank EFI | Dual Pump (Late) |
45 PSI Port / 2,400 PSI DI |
Under Rear Seat Bench |
Tips:
- Lancer Evolution High-Boost Fuel Requirements: On Evolution platforms, increasing turbo boost requires verification of the fuel pump’s static volume flow rate. An aging pump or restricted strainer can cause lean air-fuel ratios under high load, potentially leading to catastrophic engine detonation.
- Direct-Injection HPFP Check-Valve Diagnosis: For DI models like the Eclipse Cross or late-model ASX, extended warm-start cranking often indicates a failing internal check valve in the high-pressure pump. This causes a loss of rail pressure upon shutdown, which can be verified via real-time pressure monitoring on a diagnostic scan tool.