3G Alternator Install: A How To

Discussion in 'Fox 5.0 Mustang Tech' started by Roland69, Jul 3, 2006.

  1. The Green/Red Wire is what I need to tap into in order to use the FFI/RJM Harness correct?
  2. The 3G is an OEM application.

    You absolutely need circuit protection on the charge cable. When things are copacetic, you never know the fuse is there. Should an issue arise, you will be so glad you fused that thing.

    You got it. :nice:
    Your new regulator will have a terminal to loop to your lone stator connection (on the alt body), and it will have an eyelet to connect the sense (A) wire to the charge stud. That leaves the wire you connect to the grn/red wire (I).
  3. Awesome, Thanks for the Help, no extra fuses for me correct? This is my Winter Project this year, I already snagged a NOS Motorcraft 3G and I have my Power Wire and Fuse, and the FFI/RJM Harness is on the way!
  4. The way FFI has you do their retrofit harnesses, no fuse is used on the sense wire that I recall (the same is true for PA-P's harness as I recall. I recently gave away a spare one and the instructions or I'd double-check).

    However, Jrichker did bring-up a good point. I had always thought the fuse/fusible link on the sense-wire was for in case the sense-wire itself shorted out (from a chafe, etc) since this wire obviously is connected to the battery.
    With the short loop made with the retrofit, the chances of such a short are almost nill. I didn't realize the circuit protection was for the regulator itself, and in such a case, it would seem wise to fuse that wire.

    Maybe Jrichker has some more wisdom regarding how much of a risk there is with the regulator shorting out. :nice:
  5. would there be on a fuse on the back of the powermaster alternator, because the charge cable that it comes with doesn't have one, or is it something i could go pick up, Post has me thinking, I recently melted the charge wire to the fuel line right below my pressure gauge, I cut it and reconnected and was going to run the charge wire through some wire loom to the battery
  6. You definitely need an inline fuse or fusible link on the 4ga alternator charge wire going to the starter solenoid. Check the first page of this thread. jrichker has a good parts list there.
  7. If you like fire, excitement and cursing, you can use the stock wiring.:nonono:

    Seriously, how can you expect to push up to twice the power through the soda straw wiring and not have problems? You need a fire hose to deliver fire hose size power to the electrical system. See my post on first page of this tech note for a parts list and wiring instructions.
  8. sorry to bring up an old thread but I have a question.

    I recently did the 3g conversion on my 88 and I followed the diagrams in this thread where you just simply splice or tap into the smaller of the three wires in the rectifier harness and attach it to the stator port and your done.

    I haven't tested this yet because the car's down for a transmission swap that's taking way too long because of other little problems popping up as we go so what else is new.. anyways my reason for this post is because I was reading my August 08 issue of MM&FF and checked out there article in titled "dimmer switch" page 152 where they install a 3g alt, mini starter and efan. In this install they cut the rectifier wiring harness off completely and attach the stater wire to the 3g but also connect the two remaining orange/black wires from the rectifier harness to the power lug of the 3g alt.

    So my question is why did they attach the two orange/black wires to the alt's power lug and is it needed? Should I concider doing this as well or stick with what's been discussed in this thread already?

  9. Many of the ubiquitious instructions have folks reuse those stock wires. My feeling is that it's either a lack of knowledge about the issues the original wiring had or it's to allow a wider array of alternator outputs to be covered by 4 AWG cable. Otherwise, 2 AWG or numerically smaller cable would be requisite (4 AWG and the stock wires can carry almost any alternator-rating on paper, but aren't so effective in reality).
  10. I don't know if this is in this write up or not, but if you get one from a junkyard car, it's a lot cleaner and easier to tap and thread the top ear of the alternator and match it up with a bolt for mounting purposes (instead of running a long bolt and nut). This makes installation much easier.
  11. So in other words don't do it right hahah
  12. I wouldn't.
  13. So whats up with this yellow sensing wire that should be attached with the 4 gauge wire to the alt stud? I did my conversion a few months ago and still havent worked out all the bugs.

    Do you need to attach that yellow wire to the stud? Also where is the yellow wire? Is it a stock wire that is somewhere in the original wiring harness??
  14. Another thing i'd like to see is if someone could write up a how-to for the 4 eye cars with the external regulator....those cars REALLY need alt upgrades but the wiring is different and more complicated. I had to have my electrician buddy wire mine up and i didn't really pay attention enough to be able to pass it on to others.
  15. Soo could I pull the two thicker wires (orange/black) wires from the wiring harness and unhook them from the starter solenoid and be gone with them? Or do I need to keep them attach to the starter solenoid and hanging behind the starter for some reason? Also if there attached and hanging aren't the concidered HOT and kind of dangerous?
  16. The black/orange wires also joint the yellow/white wire that is the fused power feed for the regulator.
    Disconnect them and the voltage regulator has no power to make it work.

    Note the yellow/white wire has a fuse link of its own in the drawing below.

    Diagram courtesy of Tmoss & Stang&2birds

    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.

    Ignition switch wiring

    Fuel, alternator, A/C and ignition wiring

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

    Vacuum diagram 89-93 Mustangs

    HVAC vacuum diagram

    TFI module differences & pinout

    Fuse box layout
  17. thanks for the info.. looks like the org/blk wires are staying because I don't want to go hacking up the wiring.

    Much appreciated
  18. OK, so let me throw this out there then.......should you just add the additional 4ga wire on top of the orange/black that go to the solenoid? Perhaps I've missed something here. I'm so setting my car on fire.
  19. I basically asked that same question a few post up in this thread because I saw in a tech write-up in mm&ff that's what they ended up doing but everyone here suggested not to do it.