MAN ME Electronic Main Engine. Troubleshooting

Greetings! In this article, I introduce the MAN ME electronic main engine, the general concept of MAN ME engines, and examine its individual components — FIVA, ELVA, ELFI, Alfa Lubricator, and Tacho Pickup — as key systems for troubleshooting. As an example, the article examines the MITSUI-MAN B&W 6S50ME-C9.5-EGRBP main engine with an EGR system.

Modern two-stroke, low-speed engines from the ME series by MAN Energy Solutions are fully electronically controlled engines. Unlike mechanical systems, fuel injection, exhaust valves, and cylinder lubrication are controlled by electronic control units via hydraulic actuators.

This article summarizes key information on the main engine systems and troubleshooting algorithms.

The MAN ME Electronic Main Engine. FIVA, ELVA, ELFI, Alfa Lubricator, and Tacho Pickup Systems. Troubleshooting

1. General Concept of the MAN ME Engine

The ME engine is a two-stroke marine diesel engine with electronic control:

• Electronic fuel injection
• Electronic exhaust valve control
• Electronic cylinder lubrication system
• Digital speed and timing control

MITSUI-MAN B&W 6S50ME-C9.5-EGRBP

Main systems:

• ECU (Engine Control Unit) (Main Engine Control System)
• FIVA (Fuel Injection Valve Actuator)
• ELVA (Exhaust Valve Actuator)
• ELFI (Electronic Fuel Injection)
• Alfa Lubricator
• Tacho Pickup
• Hydraulic system HCU (Hydraulic Control Unit)

All processes are controlled based on signals from pressure, temperature, speed, and crankshaft position sensors.

2. FIVA — main hydraulic control valve

FIVA (Fuel Injection Valve Actuator) controls:

• injection start time
• injection duration
• supply of control oil
• exhaust valve operation (depending on configuration)

This is a key component of the cylinder.

Fuel Injection Valve Actuator

Typical Malfunctions

• Cylinder Cut-Out
• RPM Fluctuations
• Elevated Exhaust Temperature
• Uneven Cylinder Operation

Causes

• Contaminated Control Oil
• Worn Valve
• Stuck Valve
• Damaged Solenoid

Diagnostics

1. Check Cylinder Alarms
2. Compare Exhaust Temperatures
3. Check HCU Oil Pressure
4. Run a FIVA Test
5. Check Solenoid Resistance

3. ELVA — Exhaust Valve Actuator

ELVA (Exhaust Valve Actuator) regulates:

• exhaust valve opening time
• opening duration
• closing moment

Operation is synchronized with the crankshaft position.

Exhaust Valve Actuator

Exhaust Valve Actuator

Fault Symptoms

• High exhaust temperature
• Loss of power
• Alarm: Exhaust valve malfunction
• Increased cylinder pressure

Causes

• Insufficient HCU pressure
• Worn valve stem
• Oil leak
• Damaged position sensor

Diagnostics

• Check timing
• Check position sensor signal
• Check oil pressure
• Inspect mechanical components

4. ELFI - Electronic Fuel Injection

ELFI (Electronic Fuel Injection) is responsible for:

• Precise fuel metering
• Injection timing
• Pressure control

Electronic Fuel Injection

Fault Symptoms

• Misfiring
• Unstable RPM
• Increased fuel consumption
• Injection alarm

Diagnostics

• Compare fuel index by cylinder
• Check solenoid
• Check fuel pressure
• Check wiring

FIVA, ELVA, ELFI — Purpose and Diagnostics

FIVA (Fuel Injection Valve Actuator) is the main hydraulic control valve for the cylinder. It controls fuel delivery (injection), exhaust valve operation (hydraulics), and injection start and duration. FIVA receives a signal from the CCU (Cylinder Control Unit) and directs hydraulic control oil (HCU oil) to the actuators.

Typical FIVA Malfunctions

• Uneven Cylinder Operation
• Injection Misfires
• Cylinder Cut-Out Alarm
• RPM Fluctuations
• Elevated Exhaust Gas Temperature

FIVA Diagnostics

• Check for cylinder faults in the control system
• Compare: Fuel Index, Exhaust Temperature, Cylinder Pressure
• Check HCU Oil Pressure
• Run a FIVA test via the diagnostic system
• Check Solenoid Resistance
• Inspect the Control Oil Filter

Possible Causes

• Hydraulic Oil Contamination
• Worn Spool
• Sticking Valve
• Damaged Solenoid

ELVA (Exhaust Valve Actuator) is an electronic valve that controls the exhaust valve of the cylinder. It regulates the opening time, duration, and closing of the exhaust valve. It works in conjunction with FIVA and receives signals from the ECU.

ELVA Malfunction Symptoms

• Unstable Exhaust Temperatures
• Loss of Power
• Alarm: Exhaust Valve Malfunction
• Increased Cylinder Pressure

ELVA Diagnostics

• Check Timing
• Check the Signal from the Exhaust Valve Position Sensor
• Check the Control Oil Pressure
• Check the Electrical Connections
• Check the Valve Mechanism for Wear

Possible Causes

• Insufficient HCU Pressure
• Worn Exhaust Valve Stem
• Hydraulic Leak
• Damaged Position Sensor

ELFI (Electronic Fuel Injection) is an electronic control module for fuel injection on a cylinder.

• Precise injection timing control
• Fuel quantity adjustment
• Injection pressure control

ELFI malfunction symptoms

• Cylinder misfiring
• Unstable RPM
• Increased fuel consumption
• Injection alarm

ELFI diagnostics

• Check ECU (Engine Control Unit) signals
• Compare injection parameters by cylinder
• Check solenoid
• Check fuel pressure
• Check wiring integrity

FIVA, ELVA, ELFI comparison

• FIVA - Injection + exhaust - Cylinder cut-out - Oil contamination
• ELVA - Exhaust valve - High exhaust temperature - HCU leak
• ELFI - Fuel injection - Unstable injection - Solenoid

On ME series engines, most FIVA/ELVA problems are not related to the electronics, but to:

• Control oil quality
• Contaminated HCU filters
• Low hydraulic system pressure

5. Alfa Lubricator — Cylinder Lubrication System

The Alfa Lubricator system is electronically controlled and provides precise, pulsed delivery of cylinder oil.

Cylinder Control Unit (CCU)

Main Functions

• Liner Wear Protection
• Reduced Oil Consumption
• Scuffing Prevention
• Load-Based Delivery Control

MOP: Cylinder Lubrication

Alfa Lubricator

Typical Malfunctions

Low Oil Delivery

• Increasing Fe in Scrape Down Oil
• Liner Wear
• Alarm: Low Lubrication Rate

Main Engine Slow Down Based on Lubricator Feedback. Sensor Failure

Causes:

• Air inlet
• Clogging
• Plunger malfunction
• Oversupply
• Increased flow
• Soot deposits
• Ring coking

Diagnostics

• Check ALCU alarms
• Check supply pressure
• Run a supply test
• Analyze scrape-down oil (Fe, BN, viscosity)

Alfa Lubricators in MAN ME electronic engines

The Alfa Lubricators system is an electronic metered cylinder oil supply system for MAN ME series two-stroke marine engines. It ensures precise oil supply based on engine load, fuel sulfur content, operating mode (maneuvering/cruising), and RPM.

Alfa Lubricators are designed to:

• Reduce cylinder liner wear
• Optimize oil distribution around the liner circumference
• Reduce cylinder oil consumption
• Prevent scuffing
• Minimize deposit formation

Unlike older mechanical systems, oil delivery is pulsed and precisely timed during the cycle.

Main System Components

1. ALCU (Alfa Lubricator Control Unit). Electronic control unit.
2. Lubricators (plunger pumps). Separate for each injection point.
3. Pressure and feedback sensors
4. Cylinder oil tank
5. Supply lines

Operating principle

• The engine ECU transmits a load signal to the ALCU.
• The ALCU calculates the required dosage.
• Plunger pumps deliver a precisely measured amount of oil.
• Supply is synchronized with piston position.

Typical Alfa Lubricators Malfunctions

• Low feed rate
• Increased liner wear
• Increased iron (Fe) content in scrape down oil analysis
• Scuffing
• Alarm: Low lubrication rate

Causes:

• Air in the system
• Filter clogging
• Plunger malfunction
• Low oil supply pressure
• ALCU error

Excessive oil supply

• Increased cylinder oil consumption
• Coking
• Piston ring clogging

Causes:

• Incorrect feed rate settings
• Load signal error
• Sensor malfunction

Failure of one channel

• Localized cylinder overheating
• Uneven wear
• Temperature difference around the liner circumference

Causes:

• Plunger seizure
• Tube damage
• Air lock

Diagnostic algorithm

Step 1 - Check alarms

• Check alarms in ALCU:
• Lubricator Failure
• Feedback error
• Low pressure

Step 2 — Pressure check

• Check inlet oil pressure
• Check downstream pressure

Step 3 — Flow check

• Run a test cycle
• Check actual flow
• Check flow timing

Step 4 — Scrape-down oil analysis

Check:

• Fe (iron)
• BN (base number)
• Viscosity
• Water presence

Normal control

• Feed rate according to load
• Fe in scrape oil less 200 ppm (approximately)
• Flow pressure according to instructions
• Flow uniformity without deviations

Important

On ME engines, Alfa Lubricators problems are most often not related to electronics, but to:

• cylinder oil quality
• system contamination
• incorrect feed rate adjustment
• lack of regular scrape oil analysis

Practical advice

If you observe an increase in exhaust temperature and cylinder wear, always check:

• FIVA operation
• Flow Cylinder oil
• Fuel quality
• Very often the problem is complex.

Main engine slowdown. Vibration caused the wire came loose of the lubricator connector

6. Tacho Pickup — RPM Sensor

Tacho Pickup provides:

• RPM detection
• Cylinder synchronization
• Overspeed protection

The signal is used by all systems (FIVA, ELVA, ELFI, Alfa Lubricator).

MAN ME Angle Encoder

MAN ME Pickup Sensors

Typical Malfunctions

• Engine cannot start
• RPM fluctuation
• Engine slowdown
• Tacho failure alarm

Causes

• Cable break
• Incorrect clearance
• Metal shavings
• Damaged ring gear

Diagnostics

• Check alarms
• Measure resistance (≈ 500–1500 ohms)
• Check clearance (0.5–1.0 mm)
• Check signal with an oscilloscope
• Inspect flywheel

Tacho Pickup in MAN ME electronic engines

In ME series engines from MAN Energy Solutions, the Tacho Pickup sensor is a critical element of the control system. It provides accurate information on the rotational speed and position of the crankshaft. Without a correct Tacho signal, the injection system (FIVA / ELFI), exhaust valve control (ELVA), and main engine overspeed protection cannot function properly.

Tacho Pickup Purpose

The Tacho Pickup is an inductive or magnetic sensor mounted opposite the flywheel ring gear. It generates pulses as the teeth pass, transmitting the current RPM, crankshaft position, and cylinder timing to the ECU.

ME engines typically have the following:

• Main Tacho Pickup
• Backup Tacho Pickup

For signal backup.

Operating Principle

1. A flywheel tooth passes the sensor
2. An alternating voltage is generated in the coil
3. The signal is transmitted to the ECU
4. The ECU calculates the RPM and phase

The signal type is an alternating voltage (AC signal), the value of which depends on the RPM.

Typical Malfunctions

Loss of Tacho Signal

• Engine slowdown
• Engine shutdown
• RPM fluctuation
• Alarm: Tacho failure
• Failure to start

Possible causes:

• Cable break
• Loose connector
• Increased gap between sensor and ring gear
• Metal shavings on sensor
• Flywheel damage

Unstable signal

• Variations in RPM on display
• Unstable cylinder operation
• Synchronization errors

Causes:

• Poor contact
• Incorrect gap
• Interference in cable
• Partial sensor damage

Tacho Pickup Diagnostics

Step 1 — Checking alarms

Check alarms in the control system:

• Tacho input error
• Speed ​​signal missing
• Overspeed sensor fault

Step 2 — Checking resistance

Disconnect the sensor and measure the coil resistance. 

• Typical value: ≈ 500–1500 ohms (depending on model)
• If: ∞ → open, 0 ohms → short

Step 3 — Checking the gap

Measure the gap between the sensor and the ring gear. Typically: 0.5–1.0 mm (according to the manufacturer's instructions). Too large a gap → weak signal. Too small → risk of damage.

Step 4 — Checking the signal with an oscilloscope

At operating speed, you should see:

• a stable sine wave signal
• amplitude increases with increasing RPM

Step 5 — Checking the flywheel

Inspect for damaged teeth, ring gear runout, and contamination. 

• Engine won't start → No RPM signal
• Sharp drop in RPM → Signal loss
• RPM fluctuations → Unstable contact
• Overspeed → Incorrect pulse

Important for ME engines

If the main sensor fails completely, the system may switch to the backup tacho. If both fail, the engine will be shut down by protection.

The tacho signal also directly affects injection timing (FIVA), ELVA operation, and Alfa Lubricator synchronization. Therefore, tacho problems often appear as "unclear" injection failures.

Practical advice

If you experience fluctuating RPM, intermittent cylinder cut-outs, or false FIVA faults, always check the tacho signal first.

7. General Troubleshooting Algorithm

Step 1 — Checking Alarms

Always start with analyzing alarms and ECU logs.

Step 2 — Checking the RPM signal

Without a stable Tacho signal, further diagnostics are pointless.

Step 3 — Checking HCU Pressure

Most problems are related to the quality and pressure of the control oil.

Step 4 — Analyzing Cylinder Tests

• Compare Exhaust Temperatures
• Compare Fuel Index
• Check Cylinder Balance

Step 5 — Checking Lubrication

• Feed Rate
• Scrape Oil Analysis
• Plunger Condition

8. Main Causes of Malfunctions in Practice

On ME engines, problems are most often caused by:

• Contaminated control oil
• Poor-quality fuel
• Low HCU pressure
• Poor electrical circuit connections
• Incorrect feed rate adjustment

In real-world operation, most failures are complex.

The MAN ME electronic main engine is a high-tech system in which the speed (Tacho), injection (FIVA / ELFI), exhaust (ELVA), and lubrication (Alfa Lubricator) operate as a single mechanism.

A competent approach to diagnostics requires a systemic analysis, understanding the interconnections between components, monitoring the hydraulics, and checking the electronics. A proper diagnostic sequence allows for quick fault localization and minimizes vessel downtime.

Manuals! This article was written using instructions and personal experience. If you need manuals for the MAN ME electronic main engine (various models, including DUAL FUEL), I recommend our closed Telegram channel "Marine Engineering Manuals".

I hope this article was helpful. If you have any problems with the MAN ME electronic main engine, please let me know in the comments, and I will try to help you.