1984 F250 460 dual tank - Starter Relay wiring problem

[Gary Lewis]

I'm beginning to realize I have alot of checking and rewiring to do.

The electronic vacuum trouble shooting manual diagram shows the fuse link T line "hot at start". I assumed this means when the ignition is turned to the position right before the "run" (when with engine starts to crank over).

Is there a terminal on the Starter Relay that sends 12 volts when the ignition is in the start position?

If the post "I" doesn't get power until the engine starts to crank, and I hook up fuse link T to it, how would the fuel pumps prime the carb (assuming this takes a couple of seconds)

Additionally, I tested the Aux battery relay (no additional battery hooked up - just a wire feeding it power) and it shows 12 volts all the time. I assume its wired incorrectly as it's should only show power when the ignition is in start, run and acc?

And now to your questions:

The aux battery relay should have 12v to it all the time on both of the main terminals. One side would be the 12v from the main battery, and the other the 12v from the aux battery - assuming it is connected. Those voltages will be slightly different - until you turn the key to Run. At that point you should hear a loud CLICK and the relay should come in. That will parallel the two batteries and essentially make their voltages the same. Then, when the engine starts the alternator will charge both batteries.

As for the Start position of the ignition switch, that's when the key has been turned all the way and, if all else is correct, the starter is spinning. And, during that time two terminals on your starter relay will have battery voltage that otherwise wouldn't - the little "I" terminal and the large starter terminal.

Priming the carb doesn't happen until Start. Yes, that can require a bit of cranking when the carb is dry, but it isn't too bad. However, some have added a push button switch to that circuit to bring the relay in prior to cranking in order to prime the carb. You can do that by placing the switch in parallel to the oil pressure switch, and when you push the button when the key is in Run the Fuel Pump relay will come in and spin the pump. But note that you'll be sending less than battery voltage to the pump since the voltage will be dropped by the .75 ohm resistance wire. The pump only gets full battery voltage in Start. But the reduced voltage is easily enough to prime the carb.

[Ferdinand]

Welcome Josh. Love family projects! Working on my Bronco with my girls has been a great blessing. Glad you found us!