Malta MX-5 VVT MS3X Settings

[jeffives]

Hi

Just about to drop my MX-5 BP-Z3 engine into my kit car and start wiring up my MS3x and wanted to just check that I had the right set up to get started. I'm going for fully sequential without wasted spark.

So its a Malta MX-5 1.8 VVT 2004 engine with Toyota Coil on plugs 90919 02239, GM open element IAT sensor and A wideband O2 sensor. Using the stock can and crank sensors. MS3X V3 board.

So on the board itself:
Solderd a link between VRIN and TACHSELECT
Solder a link between VrOUT and TSEL
JP7 is not jumpered

Tuning settings:
Spark mode = Miata 99-05 ( Will this work with the VVT )
Trigger angle/offset = 0
Ignition input capture = Rising Edge
Spark output = Going High
Number of coils = Coil on Plug

If anybody knows if this is right that would be great.

Many Thanks

Andrew

[Matt Cramer]

Yes, '99-'05 Miata mode is what you want for the VVT motors.

You do need pull ups on these sensors.

[jeffives]

Yes, '99-'05 Miata mode is what you want for the VVT motors.

You do need pull ups on these sensors.

Hi Matt

Thanks for the reply

Is it the camshaft and crank sensors I need to put pull ups on Its just the camshaft and crank sensors only have 3 wires so do you put a 1k resistor in the signal wire

Thanks

[Zaphod]

Your trigger angle/offset will very likely be something around 5° - +/-1° but you need to verify this when the engine is running.

[jsmcortina]

General sensor wiring instructions are covered in the MS3X Hardware manual.

James

[jeffives]

Your trigger angle/offset will very likely be something around 5° - +/-1° but you need to verify this when the engine is running.

Thank you for the tip Zaphod I'll start at 5° and go from there.

General sensor wiring instructions are covered in the MS3X Hardware manual.

James

Hi James

I've had a look at the manual and tested the cam sensor and it gives off a good 5v trigger so that's fine but the crank sensor gives off around 0.6v so ill need a pull up on it. The reason I ask the question is that the manual doesn't show how to wire a pull up on a 3 wire sensor only a 4 but it does show a diagram of a 3 wire sensor with a pull up built in.

Ive added a diagram how I think it should be done but I'm not 100% sure its right.

Many thanks

Andrew

[jeffives]

Right, I don't know if the above pull up wiring diagram will work.

But I found this on the DIY Auto tune website

The CKP input also needs a pull up. You can either put this in place externally or internally.
For an external pull up, run a 1K resistor from pin 26 to pin 24 on the main board.
For an internal pull up on a V3.0 board, connect a 1K resistor on a wire from the 5V hole above the proto area to TachSelect.
For an internal pull up on a V3.57 board, solder a 1K resistor to R57.

https://www.diyautotune.com/support/tec ... our-miata/

It also says

For a pull up on the CMP input, make sure JP7 is in place on the MS3X.

But does anyone know if this is the case with the later cam sensor ? or does something else need to be done.


Cheers

Andrew

[Matt Cramer]

The later cam sensors use the same pull up.