This page is still WIP

See also Mazda-Miata-2003

Disclaimer : This page has been written by a user and thus might not be objective

A plug and play adapter board has been developped to get the car to work as easy as possible. It only requires sourcing a tock harness plug and Ampseal 23 pins headers if you want auxiliary functions. More informations are available at this link :

Proteus Plug and Play board for Miata/MX5 NB2 (72 pins)

This board is meant to run an NB2 Miata on Proteus V0.3 or above ECU. IT saves you a lot of time on crimping a custom wiring harness to accomodate OEM connector, and is overall a cheaper alternative as well. Leds indicators let you see which outputs are activated, and included flyback diode let you run the big inductive loads without risk for the Proteus low side drivers.

All the OEM pins are wired through a bridge closed by either a 0 ohm 0805 jumper or a jumper wire, letting you reallocate OEM connector pin as you want.

Two 23 pins Ampseal extension connectors allows you to wire more functions like boost control, WBO2, CAN bus communication, ETB, etc.. You can use all outputs Proteus has to offer you and on a 4 cylinder with single VVT it means a lot of extra functions.

The board pin mapping for OEM connector follows the tab given in the Pinning section below.

For the extension connectors the pinnig is the following :

PnP extension pin	Proteus pin	Type ID	Comment
1A	B21	Lowside 12
1B	B10	Lowside 13
1C	B11	Lowside 14
1D	B12	Lowside 15
1E	B23	Lowside 16
1F	B34	Ignition 2
1G	B33	Ignition 4
1H	B32	Ignition 5
1I	B31	Ignition 6
1J	B30	Ignition 7
1K	B29	Ignition 8
1L	B28	Ignition 9
1M	B27	Ignition 10
1N	B26	Ignition 11
1O	B25	Ignition 12
1P		Ground
1Q		Ground
1R		Ground
1S		Ground
1T		High Side 2
1U		High Side 4
1V	A12	12V Protected 2
1W		Ground
2A	C17	CAN+
2B	C16	CAN-
2C		VR1+
2D		VR1-
2E		VR2+
2F		VR2-
2G		Analog Temp 3
2H		Analog Temp 4
2I		Analog Volt 1	Used for MAP input
2J		Analog Volt 2	Used for WBO2 input
2K		Analog Volt 7
2L		Analog Volt 8
2M		Analog Volt 9
2N		Analog Volt 10
2O		Analog Volt 11
2P		Analog Volt 12
2Q	A21	5V Sensor 1	Used for MAP sensor
2R	A10	5V Sensor 2
2S		Ground	Used for WBO sensor
2T		ETB1+
2U		ETB1-
2V		ETB2+
2W		ETB2-

At the moment, the interface between Proteus board and the PnP adapter is handled by hacked up Ampseal connectors. To do that you need to source the male connectors used on Proteus, and cut the plastic shroud on the connector side, flush with the watertight seal if there is any, or with the mounting flange.

A better solution for that would be to source rows of headers with the correct pitch.

Unit price for QTY 5 assembled and delivered to Europe is 7$.

A few improvment would make this board really plug and play and easier to use

• For now the MAF input doesn't work because it lacks some pullup/pulldown.
• Altough they fit in OEM ECU location, ampseal extension connectors are a bit bulky. They were chosen because board designed had them lying around.

Pin Number	Name	Proteus pin	Type ID	Default function
2A	Inj 1	B3	Low-Side 1	Injector #1
2B	Fan	B9	Low-Side 11	Radiator Fan Control Relay Output
2C	A/C Fan	--	Low-Side xx	A/C Fan Control Relay Output
2D	Inj 2	B15	Low-Side 2	Injector #2
2G	Inj 3	B4	Low-Side 3	Injector #3
2J	Inj 4	B16	Low-Side 4	Injector #4
2O	-		x	x
2M	Fuel Pump	B6	Low-Side 6	Fuel Pump Relay Output
2P	IAC Feed		12V	Idle Valve Power
2Q	IAC Control	B7	Low-Side 7	Idle Valve Control
2R	MIL	B20	Low-Side 10	Check Engine Light output
-	-	-	-	-
3A	GND	A1	Power Ground	Ground
3B	GND	C19	Power Ground	Ground
3F	Coil #1	B35	Ignition 1	Coil #1 control
3I	Coil #2	B22	Ignition 3	Coil #2 control
3H	Main Relay	B5	Low-Side 5	Main Relay Control
3K	-		x	x
3L	-		x	x
3M	Alternator	B1	High-Side 2	Alternator Control Output
3N	-		x	x
3O	Tach	B2	High-Side 1	Tachometer Output
3T	VSS	?	?	Vehicle Speed Sensor
3V	Cam	C1	Digital 2	Cam shaft Hall Input
3U	Alt Warn		x	x
3Y	Crank	C10	Digital 1	Crank shaft Hall Input
3Z	-		x	x
-	-		-	-
4A	GND		Ground	Ground
4D	VVT Feed		12V	VVT Power
4K	-
4L	-	A21	5v Sensor 1	OEM 5V Sensor Power
4N	IAT	A20	Analog Temp 3	Intake Air Temperature Sensor
4O	GND	A23	GND	Sensor Ground
4P	CLT	A19	Analog Temp 1	Coolant Temperature Sensor Input
4R	VVT	B8	Low-side 9	VVT Control
4S	Key	C18	12V RAW	+12v from Ignition Key
4V	TPS	A14	Analog Volt 3	Throttle Position Sensor
4X	MAF	A25	Analog Volt 4	Mass airflow sensor, needs pulldown
4AE	EGR Boost Sensor	A16	Analog Volt 7	MAP
4AF	Main Relay Power	C23	12V MR	+12v from Main Relay

Using an external MAP sensor allows you to get the engine running above ambiant pressure when using forced induction. Good cheap option is GM 3 bars but anything will work for you. MAP input can be mapped to Analog Volt 1 (A13 pin).

Note : You can also run the engine naturally aspirated using the OEM "boost sensor". It is located on the EGR systems and is used by stock ECU to determine whether the EGR is working or not. You've probably ditched EGR so far and so you can run a vacuum line from your plenum to this sensor and use it with this calibration:

• 0V - 15Kpa
• 5V - 115Kpa

Or you can use the OEM sensor for barometric reading and correction.

VVT is quite picky to tune on the miata

You can replace the OEM 4 tooth crank trigger plate located between timing belt pulley and accessory belt pulley with a Mazda Protege trigger wheel. It is bolt on, meaning you just have to remove damper pulley to get it in place (it has a good chance to be stuck depending on car condition) and you get a way better trigger resolution of 10 degrees for a very low cost. Trigger wheel from mazda dealership was 12€ in France, available quickly. Part number is #ZM 01-11-408. For european folks your dealer might think this is an invalid number, but if he enters it the part will be offered by Mazda Europe. This modification is also applicable t any other miata with same crank bolt pattern.

Tune-wise you will need to switch to "4 stroke without cam sensor" configuration and to set your timing correctly. My offset value, verified with a timing light is 76 degrees. You can probably start your car with it, but be extra careful and check your timing with a timing light afterwards.

The gain might not be felt by everyone, but on RE the cranking will be easier, and you will get a smoother running engine. Best of all, if your fuc**** cam sensor decides to die as it does quite often you can run your car without VVT in batch injection and wasted spark and get back home safely.

Everything about this modification is detailed in the followinf thread on MiataTurbo : OEM 36-1 Wheel

OEM NB cam position sensor might die on you one day, producing trigger losses and bad misfires that happends at first when hot and then appears colder and colder, to the point you won't be able to run your car above 4k or 5k RPM. It it happens order the new sensor immediately and while waiting for it you can run without cam sync, with wasted spark (OEM config) and batch injection, but only if your crank trigger plate is asymetrical, which is not the case of the OEM one.

When ordering new sensor prefer the OEM part, even if it's more expensive. Some people cooked two aftermarket sensors in 10k km and it sucks.

If you're bored of switching your sensor with shit units to see them fail, you can always go the ghetto route and hack up your OEM sensor to use its mounting plate for an industrial grade sensor like Cherry/ZF GS1001 units. To do that you can drill the OEM body with a 12mm drill bit, the cherry sensor should thread into it. Then secure it with one or the two nuts provided with the sensor. You can adjust sensor depth to make it match OEM configuration.

Pictures to be added

• CrazyStriker's NB2 : 2004 Mazda MX5 1.8 VVT #50