After having a new engine installed I need some info on the Alternator wiring. (exciter wiring kit? for alternator) Who sales them or how to build one

[tom keyes]

After having a new 1981 engine installed I need some info on the Alternator wiring. (exciter wiring kit? for the alternator) Who sales them or how to build one? I have had issues over the years with this little Brown wire in the plug in headshell. when it is happy I have 12 volts at the volt meter. When it isn't working I have a dead Jeep. So far I have always been lucky enough to wiggle and refit it back on to keep rolling. I need to make a new setup if I can't buy something already made? Has anyone else played this game?

Thanks for ideas.

 

[sdsupilot]

Need a bit more information and/or pictures of the setup. What engine/alternator are you running?

That said its pretty common to do engine swaps with newer style alternators. I did an 89 GM TBI swap. If you google GM 3 wire alternator wiring they give pretty good examples of what is required. On mine I just put a resistor on the switched power to tell the alternator to fire up and charge.

 

[ag4ever]

If it is the stock alternator it will be a 10si or 12si. Essentially the same thing.

Should have 3 wires.

1) Charge wire to the bolt post on back of alt

2) Sense / Excite wire to the 2 wire plug on the rear edge of alt

3) Ignition switch wire to the 2 wire plug

The sense wire could feed directly to the post on the back, but that is a poor solution to making it work. This wire should connect to a splice in the main harness that feeds power to the various components. You want to read voltage here and not at the back of the alternator to determine the real voltage you are seeking at the various components, not the voltage the alternator is producing. It will be different due to voltage drop across the wire. If you sense at the back of the alternator or use a one wire alternator you could be delivering less voltage to the battery, radio, computer, lights, etc… than is really needed.

Try this as a source for wiring:

Catalog

 

[tom keyes]

It is/was the original style. two wires (one excite brown wire, one red power) attached in the head shell that plugs into the Alt. Then the red wire is attached again to the Alt, which then goes to the Starter Switch Solenoid battery terminal side. I don't see anything special about this Brown wire? Is it the wire gage or is there really a diode in line on the original wire? I have the diode that came with my MSD 6AL and have tried it and didn't see any real changes. That is sort of what lead me to ask the board if anyone else has played this? I ether get volts at the jeep volt meter or not.

 

[spankrjs]

This sums it up:

Small Brown Alternator Wire

Hi Guys, I just fired up the Jeep after replacing the BBD Carb with a Howell TBI System and noticed my alternator isn't charging. That's when I saw the wire wasn't hooked up and I forgot where the silly thing connects to. It's the small brown wire on the 2 wire connector from the Alternator...

www.cj-8.com

The brown wire is a resistor wire. It prevents the alternator from back feeding the ignition when you turn the key off, yet it allows enough voltage through itself to "excite" the alternator when you first start up the Jeep, without the need for revving the RPM's up.

You could replace it with a regular wire and a diode, if you wanted

On my red and green Scramblers, both with Hesco MPI, the kits came with a diode to install on this wire. Supposedly, even the little bit of back current that would trickle back down this resistance wire would be enough to keep the ECM/ignition engaged, so turning the key off would not shut off the Jeep

 

[tom keyes]

so it is a special wire which we need to build using a diode to make work properly. I did try the diode from MSD and I still had weird results. I put spade ends on the wire ends so I could try both ways. I will see what NAPA might have and also try a better wiring on the MSD diode.
Any other info I great though! I did run across this on line.

Alternator Delco 10S 2 wire connector plug - P10SI

Alternator Delco 10S 2 wire connector plug - P10SI

vintageautogarage.com

Thanks.

 

[spankrjs]

so it is a special wire which we need to build using a diode to make work properly. I did try the diode from MSD and I still had weird results. I put spade ends on the wire ends so I could try both ways. I will see what NAPA might have and also try a better wiring on the MSD diode.
Any other info I great though! I did run across this on line.

Alternator Delco 10S 2 wire connector plug - P10SI

Alternator Delco 10S 2 wire connector plug - P10SI

vintageautogarage.com

Thanks.

The linked part might work, not sure

The OEM brown wire is a silver, thin, single strand wire. From what I have read, the length of this brown wire is also important, but I could be wrong There is no diode on the OEM brown wire, its single strand/size makes a diode redundant in OEM/stock applications

I would try the linked part, and report back if it works, so I can redo my two Scramblers

It is a PIA trying to connect to that single strand wire, soldering is best option, but I have been known to strip enough insulation off and "double up" the single strand wire and use a crimp connector. Not the best, but will work in a pinch

Someone more knowledgeable will hopefully chime in

EDIT - I could be wrong on what wire, red or brown, that the Hesco diode is on, will have to look.

 

[tom keyes]

I ordered the part and will see what it can do. In the mean time I guess I will Fiddle with the OE brown wire. It has been such a pain at times... Like on a rock wall above Buena Vista, CO. a couple of years ago when the Jeep just quit.

 

[tom keyes]

OK guys here is where thing are. I installed the new wire. Didn't make a difference. I have turned almost every bolt on this old Jeep so I started going backwards towards the switch on the steering column. Well while my jeep was in this J-Holes shop he broke part of the cover on my tilt steering? I guess he had no clue about the activation rod in the steering column? I found where the mechanic took masking tape and wrapped it around my steering column and spray painted it black to hide the hands work. What a wimp.

It was not the exciter wire but the ignition switch on the steering column being messed with and not setup again properly. They the swtches have about 1/4" play up or down the column. I have replaced one in the past. You need to make sure the rod is in place and then do a dry run without the battery connected. it can be a pain.

 

[tom keyes]

I first thought this was the issue and did help.

"It was not the exciter wire but the ignition switch on the steering column being messed with and not setup again properly. They the swtches have about 1/4" play up or down the column. I have replaced one in the past. You need to make sure the rod is in place and then do a dry run without the battery connected. it can be a pain."


I ended up swapping back in the old Alt and wiring to see what would happen? Jeep fired up. It wasn't timed what so ever but that was a easy fix once I noticed the Dork had tried to re-run his own ideas of the vacuum system. That was a true mess once I started looking at it. Re routed the hoses to the correct ports, set the timing and now all is good. I will need to circle the wagons on the alt and wiring, but the new engine is running smooth and I hope it can also be good for the break in.

I'll maybe able to join the jeep rides in Colorado again next year? My Daughter misses it.