LF (MZR) Engine

LF (MZR) Engine

Information on the Mazda LF-VE 2.0L Engine.  This is refered to as an MZR engine and is found in the NC MX5 Miata.
They are also commonly referred to as a Ford Duratec engine, which differs from the early Zetec variants from Ford that were also called Duratec.
Volvo also use this engine under the B4204S3 and B2404S4 names.

The main focus will be on the MX5 variant.







Haltech ECU Options

Only Elite 1500 and 2500 models support these engines.





General Information

Cylinders
4
Displacement
1999 cc / 122 ci
Firing Order
1,3,4,2




CAN

This vehicle uses CAN bus for various devices throughout the vehicle. This can include the dashboard, ABS, and Body Control.




Model Variants

There are a number of variants of the Mazda LF engine.  The MX5 version is longitudinally mounted however there are transverse mounted versions of this engine in other vehicles.

LF-DE

10.0:1 comp, no-VCT, no balance shafts (found in 2.5L versions), stainless headers and cat

LF-VE

MX5 NC variant, 10.8:1 comp, Mazda S-VT (Sequential Valve Timing) on inlet cam, increased inlet valve lift, variable intake length
2009-on forged crank, new pistons, valve springs, rod bearings, 7500rpm limit 

LF-VD

Direct Injection (NOT SUPPORTED), later models get exhaust VCT and 12.1:1 comp

Known Issue

Intake

The plastic intake manifold on early versions has a major fault due to poor-quality materials. The manifold has swirlplates mounted on a square shaft at the aperture where it mounts to the cylinder head. Early four-cylinder Duratec engines can be ruined when the swirlplates break off and enter a cylinder. Most cases are of single swirlplates but also the shaft can wear and break. Early signs of this fault are evidenced by a ticking noise emanating from the front of the engine. This can occur as early as 25K miles, with failure typically occurring after about 90,000 miles.

OIl Consumption

Valve stem seals after 100k miles, rod bearing wear. 

Thermostat

Commonly fail around 60k miles.  Engine overheats or is slow to warm up.









Sensor Information

Crank/Cam Sensor

This engines uses a Crank Position Sensor and a Cam Position Sensor. 

The crank trigger wheel is part of the front crank pulley and has a total of 36x teeth. It has 1x group of 2x missing teeth, and opposite are 2x groups of 2x missing teeth separated by 1x tooth.
The cam trigger has 4x equally spaced teeth with 2x adjacent teeth having an extra tooth each.



Crank Trigger Pattern


Cam Trigger Pattern




Trigger Configuration





Crank Sensor

A Hall Effect crank position sensor is used.




  

Hall Effect Wiring
Pin
Description
Haltech Connection (Trigger 4-core)
A (G/R)
Signal Ground
Blue
B (G/Y)
Signal
Trigger+ Yellow
C (L/O)
Power (5V+)
5V+ Orange





Cam Sensor

A Hall Effect cam sensor is used.


  

Hall Effect Wiring
Pin
Description
Haltech Connection (Home 4-core)
A (L/B)
Signal Ground
Blue
B (R/B)
Trigger +
Yellow
C (LG/B)
Power 5V+
5V+ Orange








Ignition Coils

The ignition coils feature an internal igniter.  These can be wired directly to the ECU.
They are ECU dwell controlled so they use Constant Charge with a Falling edge.




Pin
Description
A
12V+ Switched
B
Ground (to cylinder head)
C
ECU Ignition Output


Dwell Time











DBW Throttle System

This engine uses a single Drive By Wire throttle body.

DBW Throttle Wiring

  

Position Sensors
Pin
Description
Haltech Connection
A
Motor -
DBW2
B
Motor +
DBW1
C
Signal Ground
Signal Ground
D
TPS 2
AVI-3
E
5V+
5V+
F
TPS 1
AVI-2






DBW Accelerator Pedal Position Sensors Connection

   

Pin
Description
Haltech Connection
A
5V+ 2
5V+
B
Signal Ground 2
Signal Ground
C
APP 2
AVI-5
D
5V+ 1
5V+
E
Signal Ground 1
Signal Ground
F
APP 1
AVI-4







MAP Sensor

This vehicle comes with a MAP sensor. This is located on the side of the intake manifold.

   

Pin
Description
Haltech Connection
A
Signal Ground
Signal Ground
B
---
---
C
5V+
5V+ (Orange)
D
MAP Signal
Spare AVI (AVI-9)

Calibration: Untested



Alternately you can use the internal MAP sensor that comes with your Elite ECU.  For higher boost levels an external MAP sensor should be used instead, connected to a spare AVI.









Variable Cams

The LF-VE engine comes with continuously variable intake cam timing control.   Mazda refers to this as S-VT (Sequential Valve Timing).
This is configured in the Haltech ECU as Cam Control. The Intake Cam 1 Input should be set to Home.  Use any spare output other than Ignition Outputs to control the cam solenoid.






Variable Intake Length

The LF-VE comes with variable intake length control.  This uses any spare output to control the switched solenoid. This is switched to be ON below 3000 RPM.






Variable Tumble Valve

The LF engine comes with a set of throttle plates located near to the cylinder head in each runner.  These are designed to improve airflow tumble under cold or idle conditions.  This can be controiled by the Elite ECU via a Generic Output.






Idle Control

This engine uses the Drive By Wire Throttle to control idle speed.







Coolant Temperature

The Coolant Temperature Sensor is lcoated on the thermostat housing at the back of the engine.

Wiring is not polarity sensitive
Pin
Haltech Connection
1
Any Spare AVI*
2
Signal Ground
An AVI with a selectable Pullup should be used.  If not and external 1k pullup to 5V should be connected.

Calibration: Use "Temperature - xxxxxxx.cal"
Created for Haltech ECUs using a 1k pullup to 5V





Air Temp

The Air Temperature Sensor is part of the MAF Sensor.  See the MAF Section for wiring information.
If the MAF has been deleted an Air Temperature Sensor should be installed in the intake.







Knock Sensor

A knock sensor is fitted to these engines and can be used with the Elite ECU.

  

Pin
Haltech Connection
A
Knock Signal
B
Signal Ground






MAF Sensor

The MAF Sensor is part of the airbox lid. Although most users of Haltech ECUs will be deleting the MAF, it is possible to use a MAF if you prefer.

   

Pin
Description
Haltech Connection
A
12V+ Switched
12V+ Grey/Red
B
MAF Signal Ground
Signal Ground
C
MAF Signal
Spare AVI
D
Air Temperature Signal
Spare AVI with pullup enabled
E
Air Temp Signal Ground
Signal Ground






O2 Sensors

This engine comes fitted with a pair of 4-wire heated narrow band sensors.  For accurate tuning the front O2 sensor should be swapped for a Haltech WB1 Wideband Kit.

For correct operation a Haltech WB1 kit is highly recommended for this application, with the provided 4.9 sensors replacing the pre-cat sensors.  Sensors use a 22mm socket or spanner to remove and replace.








Vehicle Speed Sensor

Only MX 5 NC models with Manual Transmission and no ABS/DSC system have a vehicle speed sensor.  All other models receive this data over CAN from the ABS Controller.

This engine uses a Hall Effect Vehicle Speed sensor.






Injector Data

Flow

The injector flow rate is measured with the injectors held wide open at 100% duty.  For fuel systems with a fixed regulator pressure (often returnless systems) that is not referenced to manifold pressure the flow needs to be mapped over Manifold Pressure for accurate tuning.

LF-VE Injector Flow: 240cc/min

Dead Time

When an injector is commanded to open for a certain amount of time, the dead time is the amount of time the injector is not actually open during this period.  It covers the time to energise the solenoid and begin to open and the time to close as well.  There are also transient periods during which the injector is opening and closing where fuel flow is not at full capacity so this lost peak flow period is also taken into account.  










OEM ECU Information


   

Location

The OEM ECU is located in the engine bay near the airbox.



ECU Pinout













   





















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