Alternator, Starter, and Solenoid all new

[KdkGrizz]

Hey everyone. I just replaced the Alternator, Starter, and Solenoid. All my wiring appeared to be in good condition (I know I need to start digging to be sure). Anyhow I am not getting any charge from the Alternator at all. Also showing a negative on the amp meter when the motor is running. Looking for some ideas of where to start looking for possible causes.

82 Waggy 360, Alternator is a powermaster 8002 (12si), Solenoid is Crown Automotive.

Battery is a couple years old, and does take a charge on the bench.

When I put the multimeter on the battery with the engine running it reads a pretty consistent 11.5 volts. Even after reving the motor to about 2500 rpms.

I am the first to admit when it comes to electrical issues I am an idiot !!

Help !!

[Woodchomper]

It is hard to give troubleshooting advice without knowing how you have everything wired. Pictures or a hand drawn wiring diagram of your alternator wiring would be helpful. I believe the Powermaster alternator you are using is a one wire output alternator.

For a quick test you could try hooking up the meter positive lead to the output lug of the alternator and the negative lead to the negative side of battery or ground. You should get at least 13.5 VDC.

Another thing you may want to do is to spend some time looking up Alternator Bypass wiring on this site. In your current setup you have a 100 amp alternator feeding your ammeter dash gauge before it goes back to the battery. This can become a fire hazard.

Lastly fuseable links on the solenoid go bad over time. If you have an open fuseable link you will not get power back to the battery.

[JeepJeepster]

If its a 12si then it should have the plug with two wires that plugs into it. Does it?

http://hartin.com/alternator.htm

[darylb]

I thought they had switched to voltmeters in FSJs by 82? My 73 has a voltmeter.

The Powermaster has either setup, 1 wire or 3. If you use 3 be sure you have the correct wires hooked up to the correct terminal.

More importantly if you use the 3 wire setup, don't replace, modify or solder the sensor wire. Like the wire going to your coil it is a resistance wire and if you put a regular wire in its place or modify it in just about any way you will cause problems.

I'd take the alternator to AutoZone or O'Reilley and have them test it. If it tests good and everything else is good, check your wiring.

[KdkGrizz]

I am using the factory wiring nothing new or special there. Just removed the old components and replaced them with new. Used the factory 3 wire setup. I also thought it was a 1 wire when it arrived. But after reading here and talking to the manufacturer of the alternator I removed the cap the installed over the blade terminals. So did a lot of reading and re-reading the threads on here about this issue. Seems to be a pretty common issue (charging issues). I just happen to have the dash apart so I double checked all the connections there. Still trying to figure out exactly how and where to check the resistance wire continuity. Tomorrow the new alternator comes off and old one back on as a check.

Oh I miss spoke there is a small wiring change I have installed a MSD 6al with MSD coil. Using the MSD pig tails. But I did that long before I changed out the starter, solenoid, and upgraded the alternator. Only upgraded the alternator because I am planning to add some lights etc. ok not too many etc's....trying to maintain a somewhat stock look....

[babywag]

Just because a part is new doesn't mean it cannot be bad. Have the alternator tested.
If it checks out, time to examine the wiring.

[serehill]

UH

Before you swap all that stuff at least check the wire n the back of the alternator to see if it has voltage with the engine not running. If not find out why.

[KdkGrizz]

The Battery terminal wire on the back of the alternator with the engine off is reading 11.8 volts.

And you're absolutely right BabyWag....wouldn't be the first time a new part was defective

[KdkGrizz]

Well everyone. Got home from work and decided to just grab the old alternator off the shelf and swapped it with the new one. 15 minutes later fired up the Waggy and low and behold its charging!!!! Ok now here's the rub. Took the new alternator to 2 separate auto parts store and had it tested. And what the heck it checked out good at both. Only me I swear. So I now know that my wiring is good....

Thanks for the help it's always appreciated

[KdkGrizz]

Hey guys just a quick observation. Going back to the OEM alternator which is 63amps I believe. I did.notice a change in the performance of the ignition system. I am running a full MSD ignition system including distributor. The main reason I upgraded to the 100amp alternator was my concern about feeding the MSD with enough juice. Am I way off base here ??

Be safe everyone

[babywag]

Yes, the MSD will run just fine, even on low voltage.
I forget the actual #, but it's pretty low. Below 12v IIRC.
Doubtful you would notice a difference, unless there was a problem w/ wiring.

[KdkGrizz]

Thanks for the info on the MSD. I figure eventually I will need to replace the current alternator. It could be OEM for all I know. I am only the second owner. So I would still like to replace the alternator with something with a little more juice in the future. Do I want to stay with something near stock 75-80 amps or can I move up to a 100amp without frying my charging system. Yes though all the wiring looks good. That resistance wire worries me.

[serehill]

Thanks for the info on the MSD. I figure eventually I will need to replace the current alternator. It could be OEM for all I know. I am only the second owner. So I would still like to replace the alternator with something with a little more juice in the future. Do I want to stay with something near stock 75-80 amps or can I move up to a 100amp without frying my charging system. Yes though all the wiring looks good. That resistance wire worries me.

No matter what you do as long as you don't add a lot of stuff to your system the alternator no matter how large will not draw anymore than the current used by the vehicle. It will recover better & stay more stable but it will not endanger the vehicle adding a larger alternator. Yeah it could use a little more in recharge but it is not a consequence. the old wiring & Idiosyncrasies of the jeep will burn under either circumstance.