Quote:
I pulled the purple SOL and yellow R (to non-existent coil) all the way out to the firewall, separated and then rerouted the purple SOL wire back to starter. The yellow R wire had been spliced to the resistance wire that goes into the fire wall with another spliced yellow wire that went down to the passenger side of the engine, crossed over to the driver's side between the engine and transmission and then dangled there but connected to nothing. This second yellow wire was wrapped with a green one that connected to a temperature sensor on the driver's side of the block. Very circuitous route for the green wire given that it went into the firewall on the drive's side as well. Not sure if that was factory looped around for resistance reasons or someone was having bad day when they installed it under a shade tree?
I plan to wait until after I get her running again before I cut anything, but I think I can simply cut that yellow R and the resistor wire going into the driver's side firewall out of there completely. Don't think it is needed with the HEI.
The spark test method at the battery is brilliant. Now I can wade into this and possibly avoid another smoke fest if there still is something else wrong.
|
Your assessment on the yellow wire is correct. It's purpose is to send a full 12 volts to the stock ignition coil during startup to provide a hotter spark when the engine is cold. It does this by shunting the 12 volts at the starter R terminal on the solenoid to the resistance wire, that runs from the firewall block to the positive terminal on the coil. The purpose of the resistance wire is to lower the voltage to the ignition coil and the points during normal running, to prevent them from overheating and premature failure. It connects to the pink ignition wire from the key, on the inside of the firewall block.
Yes the HEI requires a full 12 volts all the time, eliminating the need for the resistance wire and the bypass yellow wire, and in fact removing them from the firewall block, and replacing the resistance wire in the bloc with a regular 12 gauge wire to the distributor, is a common way to feed the HEI distributor
Here is a visual of the resistance wire and the yellow bypass wire. The resistance wire is the white orange purple wire on the right edge of the diagram. Follow it up to the starter solenoid and it connects with the yellow wire at the starter solenoid, and then the yellow wire runs over to the coil positive.
Here it is in the firewall block and the colors have long since faded. It is the whitish cloth covered wire.
The routing of the green wire is probably something the factory did to facilitate the installation during the build. The green wire is just a path to ground for the temperature sending unit so length is not a factor.
I though the trouble shooting method might be helpful to you and to all the other members of our truck forum. VV