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Starter Wiring: 70's Ford 4-post w/ 6.0 Powerstroke Starter

Burns

Well-known member
Joined
Jul 9, 2020
Member Number
2271
Messages
132
Loc
Portland, ME
Gents, ladies, things, and "them"......I need your help. I've been building a 1974, 6BT, 6spd crew cab F250 (Stock '74 frame with 2005+ axles, shackle reversal and front 2.5'' resis) for the last year. Its always been my dream to have a pirate build...irate build, but I've done a shit job at taking pics. So besides the point...I need help with starter wiring and hoping someone may be able to help me understand what I have going on.

Running dual batteries, a 1-wire alternator, a stock ford 4 post starter relay and the cummins conversions uses a 6.0 powerstroke starter. My question is starter wiring.
1) Do I connect the right side of my 4 post relay to one pole on the starter.....and ground the other pole of the starter to the frame?
2) Does the 6.0 starter have a relay built in..and do I need to jump it in any way?
3) Right now I have positive from the battery to the left of the ford 4 post (also where the 1 wire alternator connects), and another over to the second battery (+ to +). Then I ground each battery out independently of each other onto the frame. Right side of 4 post down to starter.....as pictured with the black wire.

I can provide more pics and answer more questions to help you guys help me. Right now I'm at a dead end...and I want this big bitch to fire up!!!

Fummins Starter 3.jpg


Fummins Starter 4.jpg


Fummins Starter 1.jpg
 
Youre close but not quite right. That starter has a built in relay. So youre gonna use the fender mounted relay to trigger the starter mounted relay.

Apply battery power directly to the large post on the starter (where you connected your large black wire). Then the right post on your fender mounted relay (where your large black wire is currently connected), will instead get a 14-16ga wire, and go to the small post on the starter. The starter will ground thru the engine/trans.
 
That starter is completely self contained. It doesn’t need the ford 4 pole to work. You put cables from both positive batter posts to the big post on the starter that currently has nothing already going to it. The other big post that has the flat strap (closest to the starter body) gets nothing else added to it. To activate the starter/solenoid you put power to the small post from your momentary power source. That’s all it takes.

Of course you know grounds are good, one good ground from the block to the frame is all you need.

As for the remote mount 4 post. If you don’t run the alternator wire through it, the truck will run both batteries dead in less than a week. I’d have to spend a few hours going through wiring in my head to explain it better.

Maybe I missed it but what gen Cummins is it? IIRC even 94 up 12V’s take a keyed power to the injection pump. I’ve never messed with an 88 to 90 whatever first gen.
 
The starter grounds through the block, do not ground any terminals down there (unless you like smoke). If you want to do it like Ford would, you can put your engine ground on one of the starter bolts and run that directly to the negative post of the battery.

You need a trigger that is 12v with the key in "crank" wired to the small post on the starter and a positive battery cable to the large post (where your black cable is currently). You don't run that cable through the relay, it's a direct connection from battery to starter. Most of the time when a guy puts a late model PMGR starter in an old Ford, you simply run a small (14ga) trigger off the right (starter) side of the fender relay down to the trigger terminal of the starter. That's the simplest/least wiring changes way.

You can also ditch the fender relay entirely and swap to a modern mini-relay to trigger the starter if you want to.
 
Youre close but not quite right. That starter has a built in relay. So youre gonna use the fender mounted relay to trigger the starter mounted relay.

Apply battery power directly to the large post on the starter (where you connected your large black wire). Then the right post on your fender mounted relay (where your large black wire is currently connected), will instead get a 14-16ga wire, and go to the small post on the starter. The starter will ground thru the engine/trans.

So my colors may be off, but given supply of wire: I can switch the black cable that is currently running down to the starter from the right side of the fender mounted solenoid to the left side of the fender mounted solenoid (which is battery +), then use a smaller gauge wire (14-1awg as you mentioned) from right side of the fender mounted solenoid to the small nut, under where my battery + is connected?

JR4X I am running a '96 12v with a ppump and a one wire alternator. Currently the one wire goes through the left side of the four post relay "back to the battery". I had a custom built harness that powers the FASS, gauges, and fuel shutoff solenoid. Basically to make the chassis and engine stuff standalone.

Ill be sure to throw a good ground on the block heading to the frame!

Nothing needs to be attached to the post with the second larger nut/flat blade on it?

Thanks for the help guys. This one really got me :smokin:
 
You can wire the starter the way i suggested, or the way JR4X suggested, either will work.

No, nothing goes to that second large stud on the starter. If you look closely youll notice, that stud already has a solid connection down to the starter motor.

So my colors may be off, but given supply of wire: I can switch the black cable that is currently running down to the starter from the right side of the fender mounted solenoid to the left side of the fender mounted solenoid (which is battery +), then use a smaller gauge wire (14-16awg as you mentioned) from right side of the fender mounted solenoid to the small nut, under where my battery + is connected?


Yes thats correct. Thats how Ford did it once they switched to that style of starter, in the mid 90s.
 
There is more than one way.
The fender mounted solenoid does two things so I retained it for my application (although not a stinky, loud, heavy diesel :flipoff2:) and wired them in series.
1. It creates 'run + start' from 'run' and 'start'. It's a 2 pole relay and the extra pole isolates 'run' once started.
2. The current draw of the solenoid on the starter is much higher than the fender mounted one, and will require more current through 40+ yr old key switch and wiring.

You can get rid of fender mount, but would need to address #1 above with diode or relay, and 'should' add another relay for #2. So just leave it and done.

Using the fender solenoid to trigger the starter's solenoid is what you will find in most searches for a PMGR starter swap, but without any reasons why.
https://www.powermastermotorsports.c...___IS_PMGR.pdf

The later model 3 post solenoid vehicles and 90's are different in that the run+start function is done elsewhere. My suggestion is specifically for ''70's Ford 4-post"
 
Last edited:
There is more than one way.
The fender mounted solenoid does two things so I retained it for my application (although not a stinky, loud, heavy diesel :flipoff2:) and wired them in series.
1. It creates 'run + start' from 'run' and 'start'. It's a 2 pole relay and the extra pole isolates 'run' once started.
2. The current draw of the solenoid on the starter is much higher than the fender mounted one, and will require more current through 40+ yr old key switch and wiring.

You can get rid of fender mount, but would need to address #1 above with diode or relay, and 'should' add another relay for #2. So just leave it and done.

Using the fender solenoid to trigger the starter's solenoid is what you will find in most searches for a PMGR starter swap, but without any reasons why.
https://www.powermastermotorsports.c...___IS_PMGR.pdf

The later model 3 post solenoid vehicles and 90's are different in that the run+start function is done elsewhere. My suggestion is specifically for ''70's Ford 4-post"



The picture in your link was the most helpful thing so far....I sucked on too many batteries as a kid and for some reason that helped to clear it up.

BUT...why is the positive coming off the battery going to the left side of the fender solenoid black...that really is fucking me. Also, that’s where my alternator power comes in. So assuming on that pole I’ll have a power from the battery, my alternator, then the cable going down to the big post on the starter.

Right side of the fender mount will contain one, smaller gauge red wire going down to the smaller pole on the starter.

off topic....but I need to attach the blue and white wire of the attached picture (fuel shutoff solenoid) to something....and is it safe to assume I can utilize the smaller poles on the fender relay for these?

i appreciate the help.....as I’m electronically inept.

66380643-2B6D-40E4-A3EB-AFD523683D5D.jpeg


55CB0EFD-BC20-40F3-9CC6-80F73B13EAFB.jpeg
 
...So assuming on that pole I’ll have a power from the battery, my alternator, then the cable going down to the big post on the starter.

Right side of the fender mount will contain one, smaller gauge red wire going down to the smaller pole on the starter.

Yes.
Blue wire to start+run on solenoid.
 
Yes.
Blue wire to start+run on solenoid.

Thanks for the input above. Your picture/diagram link saved me.

im not sure if the solenoid is working....as...well...I had to jump it. But your wiring info worked. When jumped, all works as it should.

I’ll google how to test the solenoid tomorrow.

little insight here is that I bought the truck with no engine, no batteries, basically as a roller. The wiring has been gone through by a previous owner, and I’m unsure what’s been fucked with and what hasn’t. At the end of the day, any info you may have to help me trace if the solenoid wiring (From ignition) is correct would be great.

for now I’ll walk away with this:
nevernind. Can’t upload the video of it cranking when I jumped the solenoid. Damn.

8730961C-0EC2-4BEC-A144-7AE2930C54DB.jpeg
 
little insight here is that I bought the truck with no engine, no batteries, basically as a roller. The wiring has been gone through by a previous owner, and I’m unsure what’s been fucked with and what hasn’t. At the end of the day, any info you may have to help me trace if the solenoid wiring (From ignition) is correct would be great.
By the age of these trucks is more of what's hasn't been fucked with. Hackery on top of hackery.
I suggest you get the schematic, here https://www.fordification.net/tech/wiring.htm
Looks like just one wire from switch to solenoid, R-BL.
 
A 6.4 or 6.7 starter is an upgrade to the 6.0 starter. Just thought I'd throw it out there.
 
A 6.4 or 6.7 starter is an upgrade to the 6.0 starter. Just thought I'd throw it out there.

I bought this current 6.0 starter off of amazon for $40...new, not even remaned...so when it goes, iff step up to the 6.4 or 6.7. Any info on why they are an upgrade, spin faster? more powerful?
 
Hopefully the last question. Wiring up the fuel shutoff solenoid for the 12v. I connected the blue wire to one that when ignition is on, has a constant 12v. The WHITE WIRE....I don't fully understand its purpose, but If Im thinking correctly, I can attach it to the "I" terminal on the four post starter relay.....can anyone verify if this is correct?

What I don't comprehend is the difference between the white and the blue. If the blue has a constant 12v (solenoid is pulled) when the ignition is on...why do we need the white?

Fuel Shutoff.jpg
 
The new starter always has a solenoid on it, you don't need 2 (the old fender mounted one).
you just put the new crank wire on the small terminal.
bronco_gear_reduction_starter_upgrade_07.jpg
 
The new starter always has a solenoid on it, you don't need 2 (the old fender mounted one).
you just put the new crank wire on the small terminal.
bronco_gear_reduction_starter_upgrade_07.jpg

I did just that! Solved that issue, but I am curious about the white wire for the fuel shutoff solenoid on the cummins.....is it safe to say that I can attach the white wire which the fuel shutoff designates as "Start" to the same stud on the starter (the little guy you pictures above)?
 
Nice Crew Cab! Im jelly.

As for the white wire on the shutoff solenoid. It needs to be powered from a big relay (Dodge used a massive 70 amp relay in their trucks). Coming from your ignition switch is going to cause problems, if it works at all. You could use the fender mounted relay, and instead of it powering a starter, just send a 10 gauge wire over to the shutoff solenoid from the big stud that used to go to the starter.

Clear as mud?
 
I think the fuel solenoid has a high amp draw to pull it open and a smaller current to keep it open.
I could be wrong.
 
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