alternator help

[Shields14]

ok guys i have a 68 coronet . alternator will not work .with 440 in it ,mopar electronics orange box,stock voltage regulator , i suck at electrical stuff so bare with me, my green field wire running from the voltage regulator has power to it even with the car not running  is that normal, and my alternator is not putting any power out at the stud when running, also do ineed to be running different regulator with that mopar electronic box and distributor, and what voltage should i be reading at batt, at alternator, at coil and at resisitor. any help would be greatly appreciated.

[Pete in NH]

Hi,

A stock 68 Coronet would have the older mechanical relay voltage regulator (small black box)and a single field wire alternator. The later cars with electronic ignition such as your orange box had a dual field wire alternator and electronic regulator which offered tighter voltage regulation. You may damage your orange box ignition system with the older regulator system. The older regulator was more prone to voltage spikes which can damage the electronic components in the ignition.  You can swap in a newer alternator and electronic regulator from a later (71 and up) setup. It would help if you have a reasonable understanding of auto electrics so you may want to get some help with this. Something does not sound right about having voltage on the green field wire, is this voltage there even with the ignition in the off position? If so something is not right as it should only be present with the key in the run position. Are you also saying you have no voltage at all on the alternator output stud? You should have at least battery voltage there even with the engine not running. If not, you have an open circuit somewhere in the wiring. Battery voltage ranges from around 12.6 V with the engine off to 14.5 V or so with the alternator charging the battery. Hope some of this helps, I'm sure some others will have comments as well. I don't recall if 68's had fusible links in the charging circuit between the battery and alternator, if so a link could be open.  You could also have some issues at the bulkhead connector between the engine compartment and dashboard.

[John_Kunkel]

my alternator is not putting any power out at the stud when running,

There should be battery voltage at the threaded stud whether the engine is running or not, if there isn't, check the connections...the threaded stud's source is the large threaded stud on the firewall-mounted starter relay.

[Shields14]

ya green field wire has power only when key is on. but i thought the car was suppose to be running for it to be powered up shows what i know.  no power at stud on altenator and i looked at bulk head connectors and my problem may lay there i see some melted plastic and such.  the distributor and box are just like a year old so do i need to change the regulator to a new style.

[A383Wing]

get power to alternator stud via the proper wires before replacing parts that you may not need to replace. Fix the bulkhead connector wires first, that might fix the entire problem

Bryan

[Pete in NH]

Hi,

As Brian suggested repairing the bulk head connector issue is a good place to start. Having this connector melt down on a few high current pins is a common issue on old Mopars. Here is an excellent thread about what happens and how to correct the problem- http://www.dodgecharger.com/forum/index.php/topic,33574.0.html  As to upgrading the regulator and alternator to the later version, you may not have an issue with the electronic ignition module with the older mechanical regulator, but, then again you may there's no way to tell.

[greyeagle]

Alright we'll I will tear into the bulk head and under dash wires and get this fixed. Thanks for the replies