...My father and I just finished installing our rebuilt 302 in the 73 Bronco this weekend.
Congrats on getting it installed.
The question I always ask on rebuilt engines is, are you using a flat-tappet cam, or roller cam? And if flat-tappet, have you already broken it in?
I ask because of the difficulty in getting it started, and you didn't mention cam break-in or keeping it running for awhile.
I scrambled some of your items around a bit to work with my comments.
However, we don't have crank or start from the ignition switch.
The Bronco fires up from the solenoid right away, but nothing from the key.
That says that your starter relay/solenoid is not getting a signal from the Red w/blue wire. Could be the key, could be the neutral safety switch, could be the wiring in-between.
Wondering what else it could be as we've installed all of the following items new..
- New Voltage Regulator and condenser
- New Alternator
Those are ok to ignore for the moment, since they have no effect on starting.
- New Battery
- New Starter
Also ok to ignore for now too since the engine started when you jumped the relay. Proves the battery and starter (and starter cable) are good.
- New Ignition Switch
- New Solenoid
Now these could still be at fault. You need to do some testing.
Disconnect the small Red w/blue wire from the "S" post on the starter relay and have someone turn the key to START. You should be able to measure 12v at the wire with the key in the START position.
Likely this is the issue, as you've already tested the relay with your jumper.
If you don't already have a multi-meter (volt-meter, volt-ohm meter) for testing electrical circuits, you should. Bronco owners should have one at all times it seems!
The reason you can't rule out "new" parts anymore is that they often fail quickly, or are faulty right out of the box. And the ubiquitous Ford Starter Relay is probably the most often failed new part there is.
The fact that you already tested yours by jumpering it with a wire to the S terminal (that's how you did it, correct?) you've proven that the relay itself is still good. So my money is on no power at the Red w/blue wire.
So check for power on that wire at the starter relay, then check for power on that same wire up at the ignition switch.
If no power is found in START at the switch, the switch is at fault. If you do find power up there, but not at the relay, then likely something with the neutral safety switch or it's wiring is at fault.
That's always a good thing to check, but there are no fuses in the way of this problem. No fuse controls the starter circuit.
Could it be a wiring issue?
Definitely. Follow the Red w/blue wire as your main suspect.
Also, our bronco doesnt seem to have an ICM.
Correct. They only started using the Dura Spark ignition system in '74 on some Broncos, then '75 on all the rest if I remember.
If you have not already, you can pull the distributor cap off and look for points and condenser, or an electronic trigger. If original, yours has points.
They seem to be working too, as you said the motor runs when you jump the relay/solenoid/thingy. Otherwise, the ignition has no effect on the starter cranking.
Good luck.
Paul