Using the Stepper Motor Driver to control Ignition

[rob@vems.co.uk]

Using the Stepper Motor Driver to control Ignition
In some cases it has been found that we need to drive external ignition amplifiers (ignitors) using the higher current stepper motor driver.
The wires must be swapped from the Ingition pins on the EC36 plug and moved to the EC18 plug as follow
Coil 00 EC36-pin35 to Stepper A EC18-pin4
Coil 01 EC36-pin33 to Stepper B EC18-pin10
Coil 02 EC36-pin34 to Stepper C EC18-pin5
Coil 03 EC36-pin36 to Stepper D EC18-pin11

Enable the Stepper Motor Driver
First we need to enable the Stepper motor output by setting the S259 ch7 output to be permanently on using the waterpump activation.
Go to Extras->Fan / Water Pump / FuelPump and set the water pump Start Temperature to -40 (its default) and its channel to S259 7

This activates the Stepper chip

Configure Ingition Outputs
Now we change the ignition outputs Settings->Ignition Outputs from the EC36 pins to their corresponding EC18 pins.

So that the coil drivers are mapped to the pins correctly, reflecting the wiring changes made above.

Wasted Spark
If you're interested in making life easier for yourself, or for running 6 and 8 cylinder engines using the Stepper Driver then wasted spark is answer.
First work out your injector pairing:
Four Cylinder
In a 1-3-4-2 engine, cylinders 1&4 and 3&2 can be fired at the same time.
So you connect the wires for cylinders:
1&4 to Stepper A EC18-pin4
3&2 to Stepper B EC18-pin10

Six Cylinder
In a 1-5-3-6-2-4 engine, cylinders 1&6, 5&2 and 3&4 can be fired at the same time.
1&6 to Stepper A EC18-pin4
5&2 to Stepper B EC18-pin10
3&4 to Stepper C EC18-pin5

Eight Cylinder
In a 1-8-7-3-6-5-4-2 engine, cylinders 1&6, 8&5, 7&4 and 3&2  can be fired at the same time.
1&6 to Stepper A EC18-pin4
8&5 to Stepper B EC18-pin10
7&4 to Stepper C EC18-pin5
3&2 to Stepper B EC18-pin11

Configure Ingition Outputs
Ensure that the Stepper Motor Driver is enabled as above.  Then configure the outputs, using the Four Cylinder example as above the
Go to Settings->Ignition Outputs and set the sequence:

[PeepPaadam]

Funny, I've used stepper outputs and it never needed the water pump trick? I just changed to stepper outputs and they work like a charm.

[rob@vems.co.uk]

Newer versions 1.0.73 and 1.1.18 have the stepper enabled by default, why this wasn't always the case is a mystery.

[PeepPaadam]

Newer versions 1.0.73 and 1.1.18 have the stepper enabled by default, why this wasn't always the case is a mystery.

Ok, got it!

[dundersmurfen]

just to sort things out as it is not self explaining...

some ignition amplifiers want a +12v signal right?

standard coils that we power with vems get grounded by ignition drivers built in vems (igbt) and +12v via fuse.

the so called logic level drivers when we dont want igbt drivers for ignition gives a +5v (very weak) signal?

what im getting at... is the stepper out +12v?


been using some msd coils that wants + signal. tried logic level it worked sort of, got some misfires and ecu just died, reset and worked again. is stepper the answer?

[rob@vems.co.uk]

Yes, some igniters want a +12V signal to trigger them.
The Nissan S13 coil igniters are happy with +5V, the Nissan S14 coil igniters don't do anything with +5V and only work with +12V.

Do you have any spec for the MSD coils?

[dundersmurfen]

msd coils: http://www.msdignition.com/product.aspx?id=5089&terms=8245

what i was getting at... is the s259 +12v? (all i really wanted to know for sure)

[rob@vems.co.uk]

Yes the stepper provides +12V

[mr_g]

What about VW COP's from the VEMS shop? Do they need +12V or can work on week +5V?

Do I need to put the resistor on the input?

[mr_g]

I will answer myself. It wouldn't work od +5V. After connecting it to Stepper A and B, it worked just fine.

[rob@vems.co.uk]

Cool, did you use a resistor?

[mr_g]

No. dwell time is 1.5ms.

[Denmark]

Yes the stepper provides +12V

is this right ?


/Skassa

[mattias]

Yes, it is a push-pull output.

[Bambi]

Sorry to highjack,...

Will this maybe solve my High boost misfire on AAN with LS2 UrS4/S6 Plug and Play Coil Kit ? How would I setup in 1.1.88?