not charging, light says otherwise

[brianpainter]

First post here, maybe someone can offer suggestions on what else to try. First off, not a car expert, but was gifted a 1974 spider from my father in law. Somehow he thinks I'll be able to take care of it, and fix the issues with it!! Spent a good portion of this weekend working on the charging issues, and uncovered more issues while I was at it. Here's the list of facts in some sort of timeline

Initial state:
Car starts, runs well, battery does not charge. Light in dash is on to signal no charging. Meter on battery confirms - no charging. All fuses intact

First test:
Disconnect black wires from alternator, start car and look for voltage on the alternator terminal. Voltage increasing as RPM's increase.

Second test:
Check continuity between all wires on alternator and their destination. all are good.

Discovery one:
Relay for charging light is bad (burned up). Replaced with new relay.

Discovery two:
Wire from starter to alternator is burned. Red and brown wire seem to be OK, but black wire is exposed and bubbled in places. Replaced with new wires from starter to alternator.

Discovery three:
There are not enough hours in the day or beers in the fridge to fix the charging issue in one day. Packed it all back up and back into the garage for the day.

Final State:
New relay for charging light, new wires from starter to alternator, still not charging.

When I have the black wires connected to alternator, I only see battery voltage at alternator, and it doesn't increase with RPMs. Wires disconnected, I see increasing voltage from the alternator.


Is my next step to remove the alternator and take it for testing?, or is there something else simple that I may be missing?

Thanks,
Brian

***UPDATE***
New alternator is in, and battery is happily charging at 13.5 volts while running. Charging light is functioning, and all is happy with the car for now.

[azruss]

having the alternator checked is a good idea. Where did you get the new voltage regulator. If you have the one of the drivers side inner fender, there are 2 sets of points in them. If either set is welded together, you wont get charging. They can be adjusted to bring up the running volts.

[jlferris]

You don't need to remove the alternator to have it checked you can take it to autozone or kragan or pepboys and they can quickly check the alternator and v.reg. usually free.

[brianpainter]

Thanks for the recommendations, I'll do that as my next step. The strange thing is after we replaced the burnt up relay, the charging light comes on when I turn the car on, and goes off after I start the car. So according to the light, we are charging the battery.

Will drive to the local auto parts place and get them to test the alternator.

[baltobernie]

When your engine is running at 1500 RPM, the charge light is Off, is that correct? What voltage are you reading at that state? If you're showing 13+ volts, then you're OK. Now repeat the test, with heater fan and headlights On. If the charge lamp remains Off, and the voltage is still above 13, you're good to go. The alternator only charges if the system requires it, and the recommended way to test it is under load.

ps You should never remove wires from a running alternator; the diodes can be destroyed.

[brianpainter]

Engine Running at 1500 RPM, charging light is off, only reading battery voltage at the terminal (12.4). Turning on lights and fan gives me 11.8 volts. Are you saying that it is not OK to take the black wires off of the alternator, and then turn on the car and read the voltage? I did that this afternoon and was only reading 3.7 to 4.3 volts. It did increase as I increased RPM's, but it would take a whole lot of RPM's to get to 13 volts.

I removed alternator, and am looking to replace it. Now I have a new issue: how do I get the pulley off of the alternator?

[baltobernie]

12.4 is a typical battery voltage at rest. With the engine running, you should see around 13. Since you're only getting 11 under load, you're not charging. The problem could be in the regulator, alternator or wiring. You may have damaged the alternator with your testing method. The shop where you are buying your new alternator should be able to remove the pulley. The tool is called a "wheel puller", and clamps around the back side of the pulley, pushing against the shaft. The shop can confirm the condition of your alternator and also give you detailed instructions on testing the system. Good Luck!

[brianpainter]

Ok, now I've got the new alternator from Allison automotive, but it didn't come with any instructions, so I am lost. I see where the black wires go, and I know I don't need the gray wire that goes to the regulator, so that just leaves the yellow- red wire for the charging light. There is not a male connector to plug into, but there is one wire coming out of the alternator that is green. Is this the wire for the light? Seems to be the only logical thing, but I don't want to mess anything up. Anyone have experience with the alternators from Allison auto?

[manoa matt]

99% of electrical problems on Fiats result from bad grounds. The negative side of the battery should ground to the body via the cable. If the battery is not grounded it will "appear" to charge, but will not actually charge. I'd clean the terminal ends at the battery and at the point where the cable attaches to the body. If the twisted copper strands are no longer twisted and exposed near the terminal ends its time to change out that grounding cable.