It’s Monday. I did get to work on Buzz for a while on Friday evening, but have only just now been able to sit down and bang out an update.

After giving up on the search for a local source for terminals and boots to customize my existing salvage spark plug cables, I elected to purchase a nice set of wires and hack the salvage coil connectors onto them. It actually worked out quite well.

Once I had the wires, it was a pretty simple matter to snip the old coil connector off and gently pull the connector out of the boot; it’s easy to bend and the brass won’t tolerate much bending. Then I carefully wedged the crimp apart and removed the old wire. I used needlenose pliers to bend the tabs back into a shape that looked usable, a little curve ready to bite the cable.

I cut the new wire to length, plus about an inch. Used the dielectric grease supplied with the wires to lubricate the wire and threaded it through the cap. I stripped off an inch of the insulation, folded the conductor back and manually crimped the terminal on. Crimping like this is pretty much by definition not as reliable as using a proper crimping tool, but they passed a moderate pull test. I saw now point in breaking it on purpose.

I routed the wires and installed them. Once the wires were in place, I secured the coil with nylon wire ties.

I put the rest of the system back together and tried to start Buzz up. It was a little cool out and as expected but not as hoped, I had trouble getting it to run well enough to even idle. I was able to get it to run enough to heat up exhaust pipes. Cylinders 1 and 2, warm. Cylinders 3 and 4, cold.

I played with the timing by finding TDC on #1 and adjusting the trigger wheel. Again. I toyed with the wheel and I think finally have a unifying theory of the problem.

Alert (obsessive) readers may recall that I voiced some concern about the signal voltage from the VR sensor and my thin little trigger wheel. I put my meter in bargraph mode and watched carefully as I cranked it. The displayed digits dithered between .484 and .486 volts, but the bargraph indicated a swing of .1 volts. I suspected I would know the cause of the voltage swing.

With no helper available, what I did next was kinda hard. I pulled the stock ignition fuse (well, technically my replacement of it), the fuel pump fuse and unplugged the ignition coils. I wire tied a wrench to the starter button and placed the meter where I would watch the meter and the gape between the trigger wheel and the VR sensor. I pushed the fuse in, which started the engine cranking. Sure enough, the gap between the trigger wheel and the sensor, as small an eccentricity as it may be, correlated with the swing in the output voltage.

The information in the MegaManual indicates that the EDIS module doesn’t “arm” the counter until the signal exceeds .5 volts. I know that there could be some tolerance, but the tolerance could just as well require .6 volts as .4 volts. In any case, I can definitely see where the EDIS module could be missing pulses and screwing up the timing something terrible with this bad information from the sensor.

The best way to increase the signal is to add mass to the trigger wheel. I see metal chips in my future.