CHARGING ISSUE!!!!!!

[StangzRUs]

Ok i have a charging issue problem with my 89 stang. Ok heres the deal, i got my stock 89 alternator rebuilt to 130amps, i was told from two different rebuilders that you can put all the guts of 130amp into an older alternator and not have to change any wiring, i sure hope this is true. The car wont charge, just in case i tried my buddies stock alternator and i get the same result.

The battery, starter are brand new, and the alternator has been bench tested twice at two different locations, i tryed a known good alternator and still get the same result, with the car started and running i only have 12v, but when you give it some RPM to 1800 it charges at 14.5v, is this normal?

Some how i dont think so cause i have tested my chev truck and it reads
14.4v. I did some tests on my stang and this is what i found.......

Key off/ engine off, i have 12v at the black/orange wires, and 12v at the yellow wire and i have contnuity at the white/blak wire of 0.1 Ohm.

Key on/ engine off, i have 12v at the green/red wire and when i plug the connector in i have 3.8v. I have been told there should be 2.5v when the connector is plugged in, where would the extra volt come from?

All of the wires have continuity and a reading of 0.1 Ohms

Key on/Engine Running, Probe the green/red wire at the connector and see
12v, check at battery and reading is the exact same at 12v. The voltage at the battery should read 14.5!!!!!.

I dont understand i have tried almost everything i can think of, Unless i have missed something, i hope there is some answers out there, i appreciate any help, Thanks

 

[IH8BOWTIES]

Do a 3g conversion. I spent the last 30 minutes giving detailed instructions twice but for some reason I get it all in here and I lose it all before I can post it.

Here is a link on a 3g conversion. The Corral Tech
The only problem with this method is he is using the factory wires. You will want to get about 8' of 4awg wire. A high end stereo shop should have this. I also used the factory fusible link off the donor car. I went to LKQ salvage and got my alternator for $25 with a 30 day guarantee. I also got the factory eye connector and "D" connector since it already has the stator excite wire spliced in the loom.
Do not use the factory wiring (orange/black). It's two wires that go into one and they are not big enough to handle the potential output of the 3g. You don't need to remove them just cut off the ends and cap them off. I also used 4 guage butt connectors and heavy duty heat shrink from and electrical supply company like Locke supply.
Test fit and cut the alternator bracket as described in the article but the wiring should be installed from the alternator to the solenoid routing it along the stock wiring (over and behind the radiator)
Replace the "D" plug with the "D" plug with the stator wire. Using a vice, connect the 4 awg wire to the 3g stock eye connector and seal it with the heat shrink. Route through the car following the factory routing and using plastic slit conduit to prevent chaffing. (you will need to remove battery tray)
Cut off excess cable and make the connection at with the factory 3g fusible link, heat shrink it and connect it to the solenoid in place of the stock (black/orange) wire. Replace battery tray and hook battery up and fire it up.
I have a 2800 cfm electric fan and I can run my car with everything on and I still don't drop below 13 volts.
I did the conversion in about an hour and a half. It's not hard at all. If you want more bang from you alternator, this is the way to go especially for safety reasons. If you rebuild a 2g alternator to output 130 amps, this is a dangerous situation since the spade connector and stock wiring can only handle about 55-75 amps. 130 amp alternator can output 90 amps consistently with a load. I highly recommend this conversion. The police package fox bodys had a similar setup as to what I'm recommending because there was no way the stock alt could handle police equipment and Ford knew it. That's why they went to the 130 amp 3g in 94.
I hope this helps..........Any other questions, just pm me.

 

[87GT Drop Top]

I did a 6G conversion. The case is smaller then a 3G so you don't have to grind the mounting bracket. I ran a new 4 gauge power cable. I used a 175amp fuse from a 97 F150. I got it at the junk yard. I also read it was a good idea to use a better ground from the block to the chassis. I ran a 30" battery cable from where the battery ground mounts to the block to the body right next to the battery where there is already a ground strap mounted. It charges like crazy at idle, even with the duel electric fans on high, the 1200 watt amp and the A/C blasting.

Did you try your alternator in a car that is working properly? I think you might have a ground problem.

 

[IH8BOWTIES]

This is actually a better one from right here in this forum. This is almost exactly how I did mine. http://www.stangnet.com/mustang-forums/646825-3g-alternator-install-how.html

 

[HISSIN50]

To reiterate what IH8 said because it's so important: The stock charge-wiring could catch on fire with a stock 65 amp alternator. Do NOT run any sort of upgraded alternator without upgrading the charge-cable wiring.

 

[StangzRUs]

thanks for the help, so if the wiring can not handle 130amps, why is it when i put a stock 80amp on it still doesnt charge then?????? i will look into the 3G upgrade, i appreciate the help!!!!!!!

thanks again

 

[HISSIN50]

It sounds like you have some issue going on with the car's wiring right now.

We were simply stating fact regarding the current carrying ability of 8 AWG wire.

If two different alt's that tested good still won't charge, the wiring issue needs to be found first. That is unless you rewire the alternator circuit entirely (it's easy to do and is often done with hot rods).

 

[StangzRUs]

thanks, you have a good point about the wire size. I do need to find the problem though forsure.

But i just dont know where to look any more, i have power, ground, and continuity of 0.1 Ohms in all the wires and the bulb works in the dash, im just lost with it, i guess maybe new wires will do the trick.

 

[jrichker]

Never, never disconnect an alternator from the battery with the engine running. The resulting voltage spike can
damage the car's electronics including the alternator.

Do all of these tests in sequence. Do not skip around. The results of each test depend on the results of the previous
tests for correct interpretation.
Changes in wiring for a 3G alternator are in red

Alternator troubleshooting for 86-95 5.0 Mustangs:
Engine off, ignition off, battery fully charged.
1.) Look for 12 volts at the alternator output. No 12 volts and the dark green fuse link between the orange/black
wires and the battery side of the starter solenoid has open circuited.
3G alternator: Look for 12 volts at the stud on the back of the alternator where the 4 gauge power feed wire is bolted.
No voltage and the fuse for the 4 gauge power feed wire is open or there are some loose connections.
2.) Look for 12 volts on the yellow/white wire that is the power feed to the regulator. No 12 volts, and the fuse link
for the yellow/white wire has open circuited.

Engine not running, ignition on, battery fully charged.
1.) Alternator warning light should glow. No glow, bulb has burned out or there is a break in the wiring between the
regulator plug and the dash. The warning light supplies an exciter voltage that tells the regulator to
turn on. There is a 500
ohm resistor in parallel with the warning light so that if the bulb burns out, the regulator still gets
the exciter voltage.
Disconnect the D connector with the 3 wires (yellow/white, white/black and green/red) from the voltage regulator.
Measure the voltage on the lt green/red wire. It should be 12 volts. No 12 volts and the wire is broken, or the 500 ohm
resistor and dash indicator lamp are bad. If the 12 volts is missing, replace the warning lamp. If after replacing the warning lamp,
the test fails again, the wiring between the warning lamp and the alternator is faulty. The warning lamp circuit is part of
the instrument panel and contains some connectors that may cause problems.

2.) Reconnect the D plug to the alternator
Probe the green/red wire from the rear of the connector and use the battery negative post as a ground. You should see
2.4-2.6 volts. No voltage and the previous tests passed, you have a failed regulator. This is an actual measurement taken
from a car with a working electrical system.

Engine running, Ignition on, battery fully charged:
Probe the green/red wire from the rear of the connector and use the battery negative post as a ground. You should see
battery voltage minus .25 to 1.0 volt. If the battery voltage measured across the battery is 15.25 volts, you should see 14.50 volts

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
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

 

[StangzRUs]

I did all of the tests first and i posted them, i have all the proper values that are required. Could the pulley be the problem......... do i need a stock pulley or an underdrive pulley????

 

[87GT Drop Top]

The smaller the pulley the better.

 

[HISSIN50]

If the system doesn't function properly, something is wrong. If you have reason to believe the alt is ok, and have tested the wiring and believe it to be ok, something has been overlooked. If multiple alts bench test ok but none function properly in the car, I would retest the wiring again. It takes all of five minutes to do.

 

[StangzRUs]

well i retested all the wires and got the same values. But i think it might be a ground issue, so i am replacing all of my grounds and adding new ones, i will let everyone know how i make out, thanks again for everyones opinion and ideas.

 

[Sicarius428]

Check the fuseable links. You might have fried them already with your upgraded alt.
Kevin

 

[StangzRUs]

ok i finally got a chance to figure all of this out, my car is charging with no problems now. This is what i did...........

First off i took the alternator back and got the rebuilder to change the the plug at the rectifier with a post style to except a 4G wire and not the factory harness.

Second, i replaced all of the grounds and added a few extra ones, which more the better.

Third, i ran all of the new wiring with a 100amp fuse just like it was explained in the 3G upgrade.

So i fired the car up and was charging at 13.4v at idle, much much better than 12v. still not satisfied i looked into a smaller pulley, i guess the pulley i was using was stock. So i replaced it with an under drive pulley and i have 14.5v at idle.

I thank everyone for there help and knowledge

 

[87GT Drop Top]

Glad to hear you got it fixed.