Wall of text INCOMING!
Hey guys, my jeep I loved wrenching on for years has unfortunately been sitting in a field for about 6 years now. Well I finally have the time to haul it in and have a look at it.
I swapped in a 305 sbc, 700r4 and dana 300 tcase with all the usual adapters and whatnot. For wiring it, I somehow had a bunch of relays setup with switches for the ignition/fuel (on/off switch) pump and the starter. Somehow, I had a momentary push button rigged up, that had to be pressed, while cranking with the key. It all worked when I parked it! Well sure enough after all these years have the cable runs were water soaked and ruined anyways. So I figured, F it, rip the wiring out and start from scratch when I had no idea where to start troubleshooting
So I tore out the switches and relays, jumped the HEI dist and pump straight to +12, and it eventually fired up. I guess the starter circuit is somewhat functional (more on that later).
I had a look at the wires coming out of the panel on the firewall. And heres the breakdown.
black/yellow (thin wire) - some doo hickey under the starter relay
yellow/black (thin wire) - elec choke (+12v switched power)
black - motor ground by starter relay
red x2 - Thick wire to main lug on starter relay
red/white - Thick wire to main lug on starter relay
dark green - Thick wire to starter
yellow - + 12 to alt little wire
So going with that, I tried connecting up a relay with pin 85 to the yellow/black +12v switched, 86, to gnd. 30 straight to the battery, and 87 to the positive bus I had setup for +12v switched accessories. The ignition, fuel pump and elec choke were on it. Hooked er all up to the batt, turned key to the ON position, relay clicked on, fuel pump kicked in and should be good to go.
Crank the starter, and while the starter is working I can hear (or not hear) the fuel pump. Stop cranking, and it just managed to catch fire, stumble and run, as the fuel pump came back on meaning the whole circuit was without power during cranking, so didn't get +12 to the ignition until I stopped cranking, the black/yellow got full voltage and clicked the relay. I guess there was enough momentum/gas/air in there to make it go.
Turn it off, hook up the volt meter to the black/yellow wire I'm using to drive the +12v accessories, and it drops to around 8v. BUT, before I had all the wiring sorted out I had run the +12v from the alternator to the HEI. Truck would fire up no problem (had the fuel pump connected through a diff wire). But now the truck wouldn't turn off when the key shut off, I guess the alt is still pushing 14v to the dist, keeping it running.
So I guess my problem is this, how can I get enough voltage through the black/yellow wire to drive the sense circuit on a regular bosch type relay. It's probably why I had the hot to the dist wired right to a switch.
Also, my starter relay is a friggin mess. I have no idea whats going on there. I know I had one my switch/relay setups running off the light green/white wire. But now that I've pulled all that stuff out, I don't even have it hooked up and the starter works fine with the dark green wire going straight to it.
I've attached a pic (I hope) of the starter relay wiring.
Other then that, the beast runs!