Ignition transformers with logic inputs

Although GenBoard/VerThree has onboard IGBTs so any ignition transformer designed for inductive ignition can be hooked up directly (that has no drivers), in the future we'll also look at coils with builtin drivers. These usually need a proper input with dwell-control (that is no problem for GenBoard, of course), but have some protection so a spark is fired after some time if the input is activated for too long.


We must get a good supply of these items (driverless COP transformers also). Good supplychain is always a pain to acquire.

GM Opel coilpack == GM 4cyl wasted spark ignition amplifier


Junkyard info

These are monoblock coils, epoxy filled. junkyard price is appr 45 Euro. In EU you find it in 1.6L F-Astra or G-Astra (or Vectra or other Opel or Vauxhall models). We don't have info on availability in US. However there is almost identical ignition module on Daewoo (eg. Kalos, Nubira) models with different (smaller, probably less common type) connector.


4 terminals JPT connector

Dwell info

With a running engine I could go down to dwell14=0b (700usec) when it loses it's power, but the horrible high cranking and afterstart pulsewidths demand high, dwell14>0x20 (rather >0x28) even though dwell6>90. I haven't fine-tuned it or verified power consumption yet.

Identification info

Hard to miss by the lookout. Anyway, some numbers from my unit

Measurements - Experiments

After some unsuccessful spec-googling on the Opel (GM) active coilpack (came from my Opel engine), I decided to give experiment a try.

I first connected pin3 only and than pin4 only (therefore the same mdn01 command for both output). The other one was left open, on the open input I measured 0V.

The pulse I applied was inverted with an ES2J (fast, 600V, SMB, same as used for flyback) diode and a 2k7 resistor pullup from 5V to the IGBT output (this makes it possible to use the same output for a raw transformer with max 7A and 380V). Pulse was about 4.5V for a short 1.5msec time, and normally 0.53V. To achieve this, I used ign_out=71 inverted semantics so the IGBT is switched on normally.

The PS2 keyboard froze because of the sparks. But GenBoard continued to work without reset (even though GenBoard was closer to the spark than the PS2 keyboard).

I asked my girlfriend to issue the mdn.. commands from the terminal running on the notebook (connected to GenBoard via USB-rs232), so I could watch which transformer-output fires on a given input.

Note that I'm not absolutely sure that sparks are emitted on the falling edge, but 99% sure at least.

This module looks more rugged than the Ford coilpacks (that has no driver inside). Strangely, the Ford coils seem to be more known in diy-land.

'''Note that this module fires properly driven from a weak logiclevel drive even with a 1k resistor (510 Ohm is standard now). Some active coils (VAG active COP coil was reported) needs 100 .. 270 Ohm, it just gives very weak spark from 510 Ohm.


See also