I was wandering if anyone could help me out on this one? Installed my new 3g and have a question about the exciter wire or wire that turns the alternator on at low rpm. The diagram says to use the red/green wire from the main harness that use to be connected to the regulator/alt. harness. This wire is suppose to be hot with the switch on, mine is not.I used the wire that powers my electric choke instead. The alternator is charging but it seems lower than it suppose to be, 13.8 to 14 max and drops in the 12 's with all accessories in use. This is doing no better than my old 1g alt. I replaced. I have a DUI ignition installed so I have removed the ignition module and coil. Could this be the reason the red/green wire is not hot with the switch on?, or does it matter as long as I use a wire that's hot with the switch? The truck has the charge light instead of the gauges.My 79 bronco has the gauges and it's red/green wire is hot with the switch on.Also, where's the best place to wire your aftermarket volt meter for a true voltage reading coming from your alt.? Sorry for the long post,
Thanks' Greg

 

You're gauge light seems to be burned out, if it is the Red/Green will not energize. Which doesn't matter, any wire that is HOT in RUN will work, but make sure it is full battery voltage, the old choke wire ran at lower voltage.

Did you use a new alternator or a junkyard alternator? Either way I would of tested it before installing it.

Other than that, is your low voltage all the time regardless of RPM or just at idle? The 3G needs a little more RPM at idle to kick in.

Josh

 

Thanks' for responding, everything is new from Ryan at ford fuel injection. The voltage output is as high as 14 revved up no load but drops back in the 12's under full load(ac,lights etc.) That was my thought also as to the choke hot wire. I think I will hook to the key hot side of the solenoid for a full 12 volts(brown wire) So I guess what it boils down to is to have full voltage to turn the alt. on. I will post back and let you know how it goes. Thanks' Again,
Greg

 

I grabbed my alternator from the junkyard and after installing it I added a Cyberdyne electronic volt gauge to monitor the output.

The alternator, for the most part, is usually around 14 volts, give or take.2 either way. But sometimes it spikes to 14.5 and other times it will draw down to 13.2-13.5. This is all with or without the electric fan, lights or heater being on.

This is also taken from a voltage source in the cab which shows about an average of .3 voltage drop compared to at the battery.

Josh

 

I changed it to the solenoid wire and the results are more stable. Full load or no load, 13.7-13.8 average .Just thought I should be getting in the mid to high 14s' like a lot of people. Have not been able to get in touch with ford fuel injection by phone or email. Thanks' Greg

 

This is not related to my Ford, but my daily driver 01 Mitsubishi Montero Sport only puts out about 13.5 all the time too. After the OEM alternator went out in January of last year I went through four Autozone alternators within 6 months before I got the one that is on there now. It's been on there 13 months now. It still makes me nervous even after it's been on there a year that it's not putting out around 14.4 like I feel it should. But I guess it's ok.

 

I'M gonna install my original smaller v-belt pulley and try that.