When you refer to full-time power, are you referring to KAPWR (keep alive power)?
Sort of. I should have referred to them separately, but I wasn't really thinking of the KAPWR as much as I was the main power to pass through the relays (to power the pump and ECM).
In this harness and diagram it looks like they're one and the same Black w/orange wire you're talking about. So that sounds kosher so far.
In my comment about START, RUN and CONSTANT, I was ignoring (actually I was forgetting) the KAPWR completely. For now at least that's a secondary concern anyway I think. Unless the ECM is bad, this wire should not be the cause of your issue.
So the START in my comment was Pin 30 in the engine harness up top in the diagram (Black wire?), the RUN is the wire at the bottom of the diagram marked "to ignition switch" (does not list a color) and the CONSTANT was the Black w/orange for the relays (and KAPWR).
The only thing that one wire from the ignition switch does is send 12v to turn on (energize) the EEC relay so that everything wakes up, so to speak.
By that same token though, turning off the ignition switch should completely turn off power to everything as well. Killing the engine as you would expect a normal one to function.
Your issue seems to indicate that your switched power is on all the time instead.
But does your fuel pump prime for a second or two when you first turn the key to RUN? Or does it just come on when you hit START?
Can you cause the fuel pump to run all the time by grounding the correct pin location in the TEST plug? You can see the Tan w/light green #22 wire going up to the test socket.
There are two wires that come from my solenoid.
The EEC power relay is spliced into the black/orange KAPWR wire with a 20A fused wire.
Sounds good so far. This is ok as long as the wire is connected to Pin #30 of the relay. Not to be confused with Pin #30 of the EFI harness.
The Fuel relay is spliced into what looks to be an orange wire with a 25A fused wire, although based on the wiring diagram, that could be a red wire.
The initial wire colors at the fuses may be arbitrary. Hard to say. But first thing to note would be that the Pump relay also uses the same Black w/orange wire that the EEC relay does. Which should also be to it's own Pin #30 on the relay.
Then note the other colors and locations.
The Black w/orange will have 12v all the time.
The Pink w/black will have power the first few seconds after the key is turned to RUN, then thereafter when the engine is running.
The Red #37/57 should only have power once the key is turned on and the engine is running.
The Tan w/light green is a ground, but only after the ignition switch is turned on and the engine is running.
You can test those by unplugging the relays from their sockets and using your volt-meter to probe the sockets. The pin orientations may be listed on the side of the relay, or molded in small numbers underneath where the contact pins stick out of the plastic housing. But you can also find the proper orientation online most likely.
The relay pin #'s should be:
Pin #30 should show 12v all the time.
Pin #85 should show 12v only with the key in RUN
Pin #86 should be grounded.
Pin #87 (NOT 87A by the way) should have no power when the relay is unplugged.
Again, these are the relay pin numbers. Not the numbers on your EFI harness diagram.
Those are industry standard pin numbers for the standard Bosch or Hella type relays. If yours is using Ford relays they may be different.
Looking at the wiring diagram, which I confess to know little about, there seems to be some "overlap" there. Pin 1 KAPWR connects to both the EEC power relay, and the Fuel relay.
Correct. This wire is simply a common power wire from the battery positive. This is the "hot all the time" wire we've been talking about.
It's where the KAPWR gets it's constant voltage from, but is also the same circuit that lets 12v pass through the relays from the battery and on to their specific functions. With relays, just as with other switches, some wires are redundant to reduce the amount of wiring, and can power multiple things from one wire.
Maybe someone knows whether or not you can unplug the power relay while the engine is running without harming anything in the computer. 'Cause that would be a good test.
If you pull the EEC relay while the engine is running, it should die instantly. Like if you just pulled the plug. Which essentially you did.
If it continues to run, power is sneaking in from somewhere it should not be.
But don't do that until someone more knowledgeable than me says it's ok to do.
And the same is true with the power to the Fuel relay. Pin 37 red wire goes to both relays as well? That seems wrong to me, but again, I am likely using faulty logic.
Yep, it's ok. That's the wire that, once the relays have been energized, power passes through the Black w/orange wire from the battery, through the relays and on to many things in the system. But they should by design not be powered up until the key is in RUN and the EEC relay powers them up.
In other words, I can't use the coil hot to signal or power the alternator because I have a computer run system rather than non-computer ignition. If I understand correctly.
Not sure myself. I personally like to avoid entanglements like that, but not sure what the factory does. Either way though, your old coil wire (Red w/green) is a resistor wire, so it's best not to use it for the alternator anyway. A resistor wire loses voltage to resistance after it warms up, so your 12v initially turns into maybe 8 or 9 volts in a few minutes. Not sure what that would do with an alternator.
But the Green w/red wire that you're currently using for the alternator is perfectly fine.
And doubling it up to use for your EEC relay would likely be perfectly fine as well.
Pretty sure that the RJM/Ron Francis harness that we sell uses the old resistor wire to power the EEC relay. I've never opened one up, so can't say that for sure. But it makes sense since a relay doesn't really care if it's a resistor wire or not. Usually...
Sounds like you still need to track down what wire from your Bronco harness is connected to the EEC relay.
Other than that, I have and DVM and if there are things I can test for appropriate voltage let me know.
Start with the relay sockets and go from there. If you run across any anomalies, disconnect the alternator and test again to see if there is a change.
Specifically hunt for a signal voltage from the key. One that is off with the key.
Maybe I should have said this early on, but I do know that my battery is registering as "bad" by the parts store, but he said it can do that for a year. I did however order a new yellow top that will be in in the morning... if a weak battery can be problematic.
Hmm, they do cause lots of problems when low, but usually not a situation where you can't turn the engine off. I don't think anyway. The key is supposed to be able to shut everything down via the EEC relay.
Never run across that particular scenario, but it would not be beyond belief at this point either!
Just remember that any voltages listed as 12v in our conversation are really supposed to be "battery voltage" at the time. So if you're showing 11.9 at the battery, that's what you'd want to see at the wires. You're allowed a tiny voltage drop, but anything more than 2 or 3 tenths of a volt would be suspicious and should be looked into I would think.
The only exception to that is a signal wire coming from the computer which might show 5v instead. But you shouldn't be testing those with a standard meter anyway I don't think.
And the resistor wire, which you may or may not be using at this point.
Still the best of luck.
Hope at least some of that made sense. I think I started this at 11:30 but kept getting sidetracked scanning old family photos into the computer.
Amazing what memories and feelings that 100 years of family photography brings out.
Paul
