I've got a little problem with my 76 Maverick with the 250 inline 6 engine. When I bought the car it already had a lot of new parts under the hood including a new battery, solenoid and alternator. Well a couple days after I got the car I went to crank the engine and got nothing but clicking. after I jumped her off I tested the voltage to the battery with the car running, and only got 12v not the 14v I was expecting I started looking around at the wiring and found the black and orange alternator wire that is supposed to go to the battery side of the solenoid was disconnected. I reconnected it and tested again. This time I got 14v at the battery when running. My problem is after I turn the car off, if I leave the blk/org wire connected the battery starts discharging. If I disconnect the wire it hold its charge. I've checked out the wiring to the alternator and it looks OK there are only three wires, and they appear to be connected correctly. There is a ground lug on the alternator thats not connected to anything. That wouldn't cause the battery to discharge would it? I could sure use a little help figuring this out. I'm on a fairly tight budget, and cant afford to take the car to the shop for every little problem. I know this is a pretty long winded question, but I didn't want to leave anything out that might be important. Thanks Guys.
Yes, the alternator needs to have a ground. I believe there should be ground wire in the harness to the alternator that is separate from the 3 position plug.......If not, you can probably make a ground wire to connect to the block somewhere from the alternator ground post....
No I looked and there's no ground wire in the harness. I'll rig one up after work tomorrow and let you know if it fixed the problem. Thanks
This might help: http://1bad6t.com/Maverick/repair/engine_repair_02.html or this: http://1bad6t.com/Maverick/repair/76maverickwiring.pdf
Thanks Rusty. I found the same web site a couple weeks ago. I have gone over the wiring diagram both from the 74 Mav website and the chilton's maverick manual I got on ebay. Everything looks right. The only thing I can think of is that the voltage regulator might be bad. The alternator is producing power, but if I leave it connected when the cars turned off the battery discharges. I plan running a couple tests on the regulator tomorrow. It's a pain in the u know what to have to disco the battery every time I shut off the car.
Personally I bought a meter (craftsman from sears but you can get them elsewhere) that clamps around a wire and measures current flow. Extremely useful for troubleshooting issues like these. Shut everything off and starting from the battery check the current flow in each wire. The wire pulling current will eventually lead you to the faulty component.
Even though it's new,it sounds like a bad diode in the alternator. Any auto parts store can check this for you,with the alternator on the car. Most of our stores will charge very little if anything to do this.
It is likely a shorted diode (common with rebuilt alternators). With your wire disconnected see if it will make a 12v lamp glow when you connect the lamp to the wire and battery. If it glows you need to repair or replace the alternator. A bad regulator is the second choice and it may cause the light to glow too.
If it's not the alternator try disconnecting the neg battery cable and putting a test light in line. Pull fuses one at a time until the light goes out. That should tell you what circuit has the drain. Depending on your radio you may get a slight drain for hot the wire to run the memory for the pre-sets and clock
Problem Solved!!! I am usually not the kind of guy that just throws parts at a problem until it goes away, but in this case I figured that the only part that the previous owner didn't replace in the charging system was the voltage regulator. The fact that the voltage regulator only cost $10 was also a contributing factor in this particular decision. Well this time a hunch paid off. I replaced the part as well as the battery (which had been drained to many times to hold a charge) and voila. The battery has been holding strong at 12.89v with the car turned off for over an hour now. With the old regulator, even with a fresh battery it would have been totally dead by this time. Thanks allot for all the good advice. I've learned allot about the Maverick charging system, all for the price of a $10 regulator. Happy trails.
Gotcha. With the key off, unhook the field wire (orange w/ light blue) from the alternator and check the voltage from the regulator side. It should be 0V. If its not, I would replace the regulator. If it is 0V: With the key off, unhook the light green w/ red from the regulator and check it from the harness side. It should be 0V with the key off. If its not, you have voltage coming from the cluster / ignition switch. Let us know what you find.
