My '72 is still having charging problems. It's about to drive me mad. To recap the history here, the car has never previously had charging problems during the first 50,000 some odd miles I drove it. I replaced the engine and trans (high mileage '74 250, which was not original to the car to begin with) in October 2007 with a low mileage '71 200. This engine only had 30k original miles, still had the original alternator and Autolite fan belt. The alternator went out in the first 500 miles, you could literally see sparks inside the back of it while the car was running. Replace the alternator with a new one, problem solved. Drive about 1,500 more miles problem free. Then my brother is driving the car down the interstate one night when the radio starts turning on and off by itself. The he notices the lights are getting dim. Gets home, shuts the car off, trys to restart, battery is dead. The alternator is not charging. So I decided to replace the voltage regulator and have the almost new alternator tested while I was at the auto parts store getting the regulator. Alternator tested bad. :16suspect Replace alternator and regulator. First time driving around town, all seemed well. Get on the interstate, and almost immediately, the radio starts flashing and within a few minutes the lights are going dim again. With a brand new regulator AND alternator! Figure something may be wrong with the harness that goes between the regulator and alternator, so replace it. Still no dice. Decide I'm tired of the factory setup. Research options, and decide to go with the Chevy 10SI alternator (I told them I wanted an alternator for a '78 Camaro with a 350). Get it all installed and wired up right. Let it sit there idling in the driveway for over 30 minutes with every electrical thing in the car going full blast, and everything seemed great. Drive around town for about 30 miles, no problem. About 500 miles later, the problems returned. Exactly the same problems, charges fine driving around town at slow speeds (under 45 mph), then you get on the highway and it starts going dead in a matter of minutes. Have the alternator tested, and it tests bad! Get another 10SI, triple check my wiring, find that the field coil exciter wire had melted on the header. Fixed that, then took the car for a drive. All seemed well for about 60 miles on the interstate. Then the problems came back again. Triple check my wiring again, can't find anything wrong. Close the hood and walk away, frustrated. Flash forward to today, I decide to pull a known to be perfectly working 10SI alternator off an old Oldsmobile my grandpa has sitting around and throw it on the Maverick. Same problems as always.. except this time for some reason it ate the fan belt.... Decide to put a Ford alternator back on with a new belt, same problems still. I seriously just don't know what to do. I've never had such a persistent problem with the charging system like this before. You would think it would be easy to figure out as simple as this stuff is... The only thing I haven't tried yet is the 3G Ford alternator. But I'm having a hard time shelling out that kind of money and have the problems still persist... This is driving me insane.
Jamie, where do you have the big charge and remote sensing wires hooked up to? I hooked mine to the battery side of the solenoid. The small wire for the charge light I ran a new wire inside, and put a small pilot light in line, hooking one side of it to the alt and the other side to my fuel pump switch. When I flip the switch to turn on the fuel pump, the alt gets juice to energize it telling it to start charging, and when I cut the switch off, the alt quits charging. Something was wrong with either my factory alt light or the wiring to it, thats why I just ran a new wire and light.
Not familiar with the chevy alternator but a bad ground on the voltage regulator can fry things. Thats why Ford ran the negative battery cable to the base of the regulator then over to the block. After market cables have no lug to do this so the regulator must seek its ground through the mounting screws, which corrode and rust causing a poor ground.
The car has a 6 month old battery, which tests fine. I've also tried the battery out of two other cars that were perfectly fine, and the problems still occurred. As for the grounding, I did not ever have the voltage regulator directly grounded like that. There didn't seem to be rust anywhere on it or under it. My ground cable goes from the negative battery terminal directly to the block. And then from the block to the fender apron. When checking continuity, it appeared I had perfect ground between the casing of the regulator and the negative battery cable. Bobby, for my wiring. I have terminal 2 on the alternator going directly to the battery terminal on the back of the alternator. It's literally about a two inch long 12 gauge piece of wire with a ring terminal on one end and a female push on terminal on the other end. Both terminals were crimped and then soldered on. I then have a 6 gauge cable going from the battery terminal on the alternator up to the constant hot side of the starter solenoid. My car is one of the 72's with the "Fasten Seatbelts" light in the center of the dash, so wired that into the exciter side (terminal 1). The light itself seems to work fine. When you turn the key to "on", it lights up. When you start the car, it goes out. Here is a picture I found on Google that shows exactly how mine is wired. Except I don't have the diode because I read elsewhere that you don't need it when using a charge light, because the light itself provides the necessary resistance.
Your wiring sounds pretty much like mine, except my terminal 2 runs to the solenoid with the battery wire. It must be some kind of ground issue, sounds like you have the positive side covered....
I can't seem to find any problems with the grounds. They are clean, the cables are brand new, and when poking around with a continuity tester, everything seems fine. This is frustrating as hell.
Nope, it's just the factory Fasten Seatbelts light in the middle of the dash. The bulb in it is small, but it's not an LED.
Check your ground wires with a volt meter - not a light or ohm meter. put the red lead from your volt meter on the cable end farthest from the negative battery terminal and the black lead on the cable end (same cable) closest to the negative battery terminal. If it reads .5 volts or more there is a problem with the cable and it needs to be replaced or repaired. You can check the alternator ground by putting the red lead on the alternator case and the black lead on the engine block first - then move it to the metal on the fender well and finally on the POST of the negative battery post. If you get .5 volts or more at any location then that is where your problem is. Lights are good for emergency use but a volt meter (even a cheap one from Harbor Freight) is MUCH better.
I am using a volt meter. My grounds are fine. I picked up a newish looking 3G alternator at Pull-A-Part today for 16 bucks. Came from one of the dozens of '93-'94 3.8 Tauruses there. Just need to find someone with a good strong impact gun to swap the pulleys for me before I can install it.
Get a 4 ga. cable to run from the 3G alternator to the solenoid. and make sure your grounds are just as big. That alternator can push as much amperage as your starter can use. Oh, and don't forget to remove the ammeter if you have one. You can't push 130 amps through 10 gauge wires and a 60 amp ammeter - they catch on fire!
