Check your bulk head connector

[Paul G]

I just installed a Holley electric idle solenoid to kick the rpm's up when the A/C is on. Not that I am using the A/C right now, but, I just installed it. It would not hold the carb open very well. The voltage I was getting to the solenoid was only about 11 volts. Holley wants at least 12.5 they say.

I am using a relay to power the A/C clutch and solenoid. The relay contact power comes from the fuse block "bat" terminal, this is power directly from the battery and alternator. Still I was losing voltage somewhere. I disconnected the bulk head connector to check the condition of the terminals for the alternator wire and the battery wire that pass through the connector. Both were badly charred and crispy. The terminal connectors were discolored and brittle, the plastic plugs were dark brown from the heat that had been building up due to the poor conductivity of those old terminals.

I ran two new 10 gauge wires from the alternator, and the starter solenoid (battery). I drilled out the original terminals in the bulk head connector and ran these new 10 gauge wires right through it to an auxiliary fuse block I picked up at Napa. The new fuse block had a screw terminal to land the "hot" wires to. I landed both the alt, and bat, wires to the screw terminal as well as another wire to supply power back to the old factory fuse block circuit since the original wires that went to it, bat and alt wires, are now disconnected. Bypassing the factory amp gauge was part of this. There are multiple threads for that. Nacho has great diagrams in them as well. You could do this without an additional fuse block, or bypassing the amp gauge, by just running the new wires through the bulkhead connector and splicing them to the original wires on the inside of the firewall. My A/C relay power now comes from a fused circuit in the new fuse block. I can feed other electrical devices like an amp, electric fans, electric fuel pump, etc. from the new fuse block.

I am now getting a solid 13.2 volts to my idle solenoid with the engine running. Battery voltage with the engine off. Besides having stronger voltage to my accessories, I feel that I have eliminated a potential fire hazard from 30+ year old wiring.

[Bob T]

Hi, yep, mine were fried in my 68 also and I have performed a similar fix and rewired a fair amount of the engine bay at the same time.
Also had an overvoltage issue sorted recently, the battery had sulphated up and increased the base level voltage up to 13 at rest and it climbed dramatically when the revs increased up to 16.2v and fried the new V.reg straight away. Spent quite a while testing the wiring out until we found the underlying cause. Fixed with new battery and reg so all good now.

Cheers Bob