1989 5.0 3g Alternator Conversion.

Window

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Feb 13, 2017
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Im fairly certain i have all the information i need but have a question unique to my circumstances. ive always had a charging issue with this car and its been in the shop years ago because i wasnt confident enough to get at it myself. either way the issue i had was fixed for a little while but once again the fusible link going to the starter solenoid has blown. im going to be installing a 130 amp 3G with a 4 gauge power wire. At the moment my current 2g alternator 10 gauge orange/black wires are fused with a 14 gauge link and the 18 gauge voltage regulator wire(i think) that usually spliced into the 10 gauge orange/black wires is separately spliced which i think was done at the shop i brought it to. My question is can i just cap off both ends of that 10 gauge orange/black power wire (where the 14 gauge fusible link is toasted) and leave the 18 gauge voltage regulator wire independently linked to the starter solenoid without any problems? Again i will be installing a 4 gauge power wire with the new 130 amp 3g with an inline fuse. Sorry in advance for the short story.
 
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jrichker

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http://www.stangnet.com/mustang-forums/threads/3g-alternator-install-a-how-to.646825/#post-6673702

Alternator wiring.

attachment.php?attachmentid=50374&stc=1&d=1179322644.gif


3G rear view 75%.GIF


If you have a 3G alternator, the white/ yellow wire is critical to proper operation. It is the voltage sense and regulator power lead that picks up the difference in voltage at the alternator output stud and the connection point at the starter solenoid. If you cheat and run it directly to the alternator output, it sees the voltage at the alternator output stud. It does not see the voltage at the starter solenoid connection point where it feeds power to everything else. You may have a voltage drop in the wiring between the alternator output stud and the connection to the starter solenoid. Thus you may have low voltage or less than the standard regulated voltage at the starter solenoid connection point. This makes for low voltage throughout the rest of the car: everything operates at less than full efficiency.

Starter solenoid wiring 86-91 model cars.

Connect the fused 4 gauge wire to the alternator and the battery side of the starter solenoid.
attachment.php?attachmentid=52294&stc=1&d=1192414749.gif
 
Last edited:

Window

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Thats the exact guide im following but its a little different because my 10 gauge power (orange/black) and 18 gauge voltage regulator (yellow) are separately attached to the starter solenoid. i want to remove the power all together and leave the voltage regulator attached alone if it wont cause any problems.
 

Window

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View: http://imgur.com/a/Yotjk

Left wire is the 18 gauge voltage sense. Right is the 10 gauge orange/black with what im pretty sure is a fried fusible link. i want to cut down the orange and black here and also.....
View: http://imgur.com/a/I4N4X.....here
at the opposite where it becomes one wire and just tape off the now dead wire that is not attached to anything. then proceed with the 3G conversion as normal with the 18 gauge voltage sense wire on the left in the 1st picture directly attached to the starter solenoid without the orange/black wire.
 

jrichker

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View: http://imgur.com/a/Yotjk

Left wire is the 18 gauge voltage sense. Right is the 10 gauge orange/black with what im pretty sure is a fried fusible link. i want to cut down the orange and black here and also.....
View: http://imgur.com/a/I4N4X.....here
at the opposite where it becomes one wire and just tape off the now dead wire that is not attached to anything. then proceed with the 3G conversion as normal with the 18 gauge voltage sense wire on the left in the 1st picture directly attached to the starter solenoid without the orange/black wire.

That should work.
I left all the old wiring in place just in case I needed to revert back to the original alternator in an emergency.
 

Mustang5L5

i'm familiar with penetration
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Feb 18, 2001
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And solder your joints, those connections look like they where screaming in pain.

Yeah. +1 on solder

Butt crimps can loosen as the wire moves around, loose connections are high resistance which creates heat, heat makes things melt. Melting can lead to fires.

Solder + heatshrink