EDIS4 w/ COP
I'm running a Ford EDIS4 (electronic distributorless ignition system, four cylinder) ignition system on my 99' miata running MegaSquirt II Extra (MS2E). The ford EDIS4 ignition system uses a 36-1 trigger wheel driven by the crankshaft. The VR sensor reads the wheel and its signal goes to the ford EDIS4 ignition module. The module is the heart of the system. It reads the VR sensor to establish the position of the engine. The module has the igniters built in, and drives a pair of coils in wasted spark configuration. It also adjusts dwell automatically via current limiting, which makes upgrading ignition coils easy. If you aren't running boost, the stock coils will fire a .055" gap plug all day long. But with boost, stock coil pack sucks, so either get a MSD coil pack or switch to COPs.
The ford EDIS4 modules are considered bulletproof, as they've proven to handle high heat from engine compartments, vibration, water, you name it reliably with virtually no reported failures. They're almost impossible to kill and pretty much last forever. They have several fail safe features built into them. For example, if the coil wires short together, the module will shut off the igniters to prevent burning them up. It will also fall to 10* BTDC if it ever looses the timing signal from the ECU. And if your VR sensor goes bad (read, fucker is falling apart), it will still run below 2000 RPMs.
They are simple to wire up too. Three wires go to the coils, two to the VR sensor, two to the ECU, ground, and switched fused +12V.
You do have to mount a 36-1 trigger wheel to the crankshaft and build a bracket to hold the VR sensor next to it. This is the hardest part, but this is why you get 5/32 of a degree spark accuracy. Much better than belt driven shit which can be several crank degrees off.
You can get the entire system off of an old ford 1.9L escort in the junk yard, or a mercury tracer w/ 1.9L. The 1.9L is the only 4 cylinder ford out there with a tubular aluminum intake manifold, so it's hard to miss. I originally bought all the shit from one off of ebay for 50 bucks shipped, but I've since bought it from the local yard, $25 for the entire ignition system, wheel, VR sensor w/ plug, module w/ plug, coil pack, sparkplug wires.
I eventually put a set of COPs on. Bought the connectors w/ wire PICO part number 5713PT
http://www.summitracing.com/parts/PCO-5713PT/ from summit @ 4 bucks each and searched for "ford 4.6 coil" on ebay and bought the cheapest NEW set of 8 coilpacks on there, 85 shipped for 8 IIRC. All the coil packs for the 4.6 are made by the same company, in the same place, so "brands" don't matter. I have four extra coils and connectors….
Wired them up using this diagram
http://img.photobucket.com/albums/v399/ogip/Edis_forcopnew_series.jpg and they work great.
My wiring harness
http://i231.photobucket.com/albums/ee155/patsmx5/100_0808.jpgMy ghetto trigger wheel setup. Works, but will be redone eventually.
Hub I made….
http://i231.photobucket.com/albums/ee155/patsmx5/coolshit4.jpgWith wheel pressed on
http://i231.photobucket.com/albums/ee155/patsmx5/triggerwheel.jpgNew VR sensor bracket I made. Simple and works.
http://i231.photobucket.com/albums/ee155/patsmx5/100_0861.jpg