BP-4W Engine 99-00 "NB1"
Information on the Mazda MX5 Miata NB1 BP-4W engine
General Information
| Cylinders | 4 |
| Displacement | 1839 cc / 12.2 ci |
| Firing Order | 1,3,4,2 |
Common Models
Found in the 1999-2000 Mazda MX5 "Miata" NB1
Sensor Information
Crank/Cam Sensor
This engines uses a Crank Position Sensor and a Cam Position Sensor. The crank trigger wheel has 4x teeth on a plate bolted to the back of the inner belt pulley, with 2x opposite teeth slightly offset. The cam trigger is on the front of the inlet camshaft gear and has 3x teeth with 2x teeth 180 degrees apart and one of the teeth have a close extra tooth.
Crank Trigger plate
Cam Trigger on Cam Gear
Crank Sensor
A Hall Effect crank position sensor is used. This is located in the front of the engine towards the right hand side of the crankshaft and is held on by a single bolt. This can come loose if bumped and allow the air gap to change.
Hall Effect Wiring
| Pin | Description | Haltech Connection (Trigger 4-core) |
| A | 12V+ Switched | Red |
| B | Trigger + | Yellow |
| C | Signal Ground | Blue |
Cam Sensor
A Hall Effect cam sensor is used. This is located on the front of the inlet camshaft. The connectors on these sensors are prone to having a bad connection which leads to issues.
Hall Effect Wiring
| Pin | Description | Haltech Connection (Home 4-core) |
| A | 12V+ Switched | Red |
| B | Trigger + | Yellow |
| C | Signal Ground | Blue |
Ignition Coils and Igniter
This engine has Waste Spark ignition with a pair of dual-post ignition coils mounted to the rear of the cylinder head.
The ignition coils feature an internal igniter. These can be wired directly to the ECU. Set to Waste Spark mode with Constant Charge with Falling Edge.
| Pin | Description | Haltech Connection |
| A | 12V+ Switched | --- |
| B | --- | --- |
| C | Ground to Cylinder Head | --- |
D | ECU Signal | Ignition Output |
Dwell Time
Throttle Position Sensor
This engine uses a cable operated throttle body with a position sensor.
Pin
Description
Haltech Connection
A - (Light Green/White)
5V+
5V+ (Orange)
B - (Black/Red)
Signal Ground
Signal Ground (Black/White)
C - (Green/Black)
TPS Signal
Spare AVI (AVI-10 White)
| Pin | Description | Haltech Connection |
| A - (Light Green/White) | 5V+ | 5V+ (Orange) |
| B - (Black/Red) | Signal Ground | Signal Ground (Black/White) |
| C - (Green/Black) | TPS Signal | Spare AVI (AVI-10 White) |
MAP Sensor
These engines do not come with a MAP sensor.
Use the internal MAP sensor that comes with your ECU. For higher boost levels an external MAP sensor should be used instead, connected to a spare AVI.
Idle Valve
This engine uses a 2-pin BAC (Bypass Air Control) Valve which is duty controlled by the ECU via 1x output.
2-pin BAC Wiring
| Pin | Function | Haltech Connection |
| 1 | Open Signal | Spare Output |
| 2 | Power | 12V+ Switched |
Coolant Temperature
This engine has a 3-pin Coolant Temperature sensor. 2x pins are used for the ECU sensor, and the other pin is for the gauge sender and grounds through the block.
| Pin | Description | Haltech Connection |
| A | CTS Signal | Any Spare AVI* |
| B | Signal Ground | Signal Ground |
C | Gauge Sender Signal | --- |
An AVI with a selectable Pullup should be used. If not and external 1k pullup to 5V should be connected.
Air Temperature
This engine has an Intake Air Temperature sensor located in the OEM air filter housing. If this is removed or the MAF is deleted then a new ATS shodl be added to the intake as close to the MAP sensor source location as possible.
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.
Knock Sensor
This engine comes with an older style resonant knock sensor. This can be used with the Haltech Elite 1000 and higher ECU however this style of sensor is known to be unreliable and not suitable for heavily modified engines. If issues are experienced it is recommended to move to a donut style non-resonant knock sensor.
| Pin | Haltech Connection |
| A | Knock Signal |
| B | Signal Ground |
MAF Sensor
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 (Black/Blue) | Signal Ground | Signal Ground (Black/White) |
| B (Pink) | MAF Signal | Spare AVI |
| C (White/Red) | 12V+ | --- |
O2 Sensors
This engine comes with Narrow Band O2 sensors. These can be used for emissions related tuning however a Wideband O2 kit is required for normal engine tuning.
Adding a Haltech Single-Channel Wideband WB1 Kit (highly recommended)
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.
VICS (Variable Inertia Charging System)
This engine has a switched variable intake length system that opens a resonance chamber, named by Mazda as VICS. This can be controlled by the Haltech ECU via the Dual Intake Runner function and simply uses a spare output to activate the solenoid. The solenoid is ON below ~5200rpm.
Vehicle Speed Sensor
This engine uses a Reluctor Vehicle Speed sensor. This sensor signal is sent to the speedometer where it is converted to a digital Hall Effect style signal that is sent to the ECU. The Haltech ECU will read this signal and needs to be set as a Hall Effect sensor type with a Falling edge and Pullup will be Disabled.
If wiring directly to the sensor. Set to Reluctor with Falling edge
| Pin | Description | Haltech Connection |
| 1 | Signal | Any Spare SPI |
| 2 | Signal Ground | Signal Ground |
Approximate Calibration Pulses Setting: 2780 pulses/km
Alternator Control
This engine has an alternator that requires a high side drive duty signal to control the alternator charge voltage. This is done by using a Stepper output from the Haltech ECU and setting the Active State and Drive Type to High.
| Pin | Description | Haltech Connection |
| P (Grey) | Feedback Volts Signal for ECU | --- |
| D (Grey/Red) | Duty Signal from ECU | Spare Stepper Output |
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.
Injector Flow: 265 cc/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 ECU is located under the passenger floor panel near the firewall.
ECU Pinout
Base Maps
Base maps have been created for use with the Haltech Elite Adapter Harnesses.
To use these maps they should be IMPORTED into your ECU. Follow the IMPORTING A BASE MAP guide.
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