Modified Engine Wiring- 3 hours (336 Total)

Today I did some rewiring of the electrical system to fix some of the problems seen yesterday.

The first thing I did was trouble shoot my rev counter. I used an oscilloscope to look at the rev counter signal. I am using the trigger wire that connects the coil to the CDI. The signal I saw was a negative pulse in the range of 200v. The inactive portion of the waveform seemed to be clean and appeared to be at zero volts. I assumed that the RDAC wasn't able to see this negative pulse so I mocked up a setup that connected it to one of the AC lines of the alternator. This gave me a signal the RDAC could read. Looking at the wave form again surprised me. I was expecting a sinusoidal wave; instead, I saw a very square pulse up to 12V. I then, permanently, rewired the rev counter input to the AC wire of the regulator.

Since I had my oscilloscope handy, I used my current probe to see what was going on with my starter solenoid. I could see 40amp and sometimes 80 amp spikes on the starter solenoid. My installation has two fuses between the starter solenoid and the battery. The Master fuse which is 20 amps and a 3 amp fuse to power the RDAC, Fuel Pressure sender, and the starter solenoid. The schematic from Hpower does not have this second fuse. My solution was to rewire the system to be more like the Hpower setup; I connected the solenoid directly to the Master circuit.

Downstream from the solenoid is the starter switch; but between the two is approximately 12 feet of 22AWG wire. The wire will easily deal with the DC load of the solenoid but I don't know if it would have any issues with the 80 amp spikes. I decided to err on caution and use the one spare 22AWG wire to share the load.