Autosport Labs

Good power & ground are critical. But if those are OK, the random failure nature sounds like a failing transistor (an EDIS4 coil driver). Regarding grounds, any nut & bolt through plastic will come loose when the plastic yields to pressure a tiny bit. So to secure these I use 2 nuts tightene...

The gap test, is just to see if VR noise pickup or vibration are a problem. If the gap (and induced signal level) have no effect on the problems, they are likely not the source of the problem. Bruce

Here is an update on the tractor performance, after about 5 hours operation. It starts better (cranking retard), and accelerates better. I'm seeing another 200 rpm in many situations, with no governor mods. It no longer tends to stall when losing a lot of rpm on the really tough grass. Instead of ru...

It sounds to me, like a weak spark system. You already swapped the coils & wires, but the coil drivers in the EDIS4 could be weak. Another experiment would be to try the VR gap at .030" and .060", no difference in problem implies the issue is elsewhere. Bruce Roe

If a voltage excess blew up one integrated circuit, it likely damaged all the ICs. Even an IC that seems to have survived, may fail soon (happened to me). I'd replace them all.

Is there a V4 schematic diagram available? Bruce Roe

What is the way to unplug those EDIS connectors, without breaking off either of the retaining tangs? Bruce Roe

That 440 is an excellent example, of how the wires & coil packs should be arranged. Bruce Roe

I just take a view of the engine, and draw lines between cylinders that will be on the same coil. The lines will make it obvious how the coils can be placed to minimize lengths. Put a coil pack where 2 lines cross. And any coil can be "COIL A", etc, as long as the right 3 primary & sec...

I'd just wire coil A to plugs 1 & 6, coil B to plugs 8 & 5, coil C to plugs 4 & 7, coil D to plugs 3 & 2. Primary of coil A to EDIS8 pin 8, primary of coil B to EDIS8 pin 9, primary of coil C to EDIS8 pin 11, primary of coil D to EDIS8 pin 12. Bruce Roe

Be sure there are 2 wires in addition to the shield. How long do you need, what is your address? Bruce Roe

For the VR pickup, you need a twisted wire pair inside a shield (3 conductors), which is grounded at the EDIS end. That isn't coax which has only 2 conductors. I used some off an old roll of alarm sensor wire, guess I could spare some. Bruce Roe

An even fire 3 is like a 6 with half the cylinders missing. It takes 2 turns, 720 degrees to hit everything. At zero degrees, 1st coil fires your first cylinder in the firing order. At 120 degrees, 2nd coil waste fires the 3rd cylinder in your firing order. At 240 degrees, the 3rd coil fires the 2nd...

I believe a EDIS 6 would work, one end of each coil grounded. Bruce Roe

I believe a EDIS 6 would work, one end of each coil grounded. Bruce Roe

The EDIS will run with a limp mode 10 degrees advance, without help from the MJLJ. Anything more complex must be stored & executed at the MJLJ. Bruce Roe