1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Alternator not charging?

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Old Mar 4, 2008 | 10:24 AM
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Alternator not charging?

I have an '83 with a stock alternator. I have just replaced the motor and am trying to get it going. When I turn on the key the volt gauge shows 12 volts. When I start the car it does not move. The tac is not working either.

When the car is shut off the (B) terminal shows 12 volts. When I turn the ignition on the R and L terminals show 12 volts. The alternator worked fine with the old engine so I have not tested it yet.

Also I have removed the rats nest wiring and I now have a RB holley carb setup. I may have messed up the wiring when I removed the rats nest wiring.

I have searched and found a number of threads on this but I am still lost.

Thanks for the help.
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Old Mar 4, 2008 | 10:29 AM
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Do all of the warning lights come on when the key is 'ON' and then shut off after the car has started?

For the tach not working, either the trailing ignitor is bad or you are missing a connection (or broken wire) to the trailing coil (-) terminal. Have you checked for spark on all plugs?
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Old Mar 4, 2008 | 10:45 AM
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The lights do come on when the key is on and shut off when the car is started.

I have not checked for spark on all the plugs and I will check that tonight. What is the best way to do this?

I will test the trailing ignitor tonight also. I am guessing it is good, it worked the last time the car ran.

Is there a way to test the wiring to the (-) trailing coil without opening up all the wire loom?
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Old Mar 4, 2008 | 10:54 AM
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Check the FAQ for online manual linkage. Good diagrams and test procedures for all the Electrical stuff in there.

I would suggest you disconnect the battery for a while. And trace the connections again. Starting with the starter, fuseable links, blade fuses, cables etc.
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Old Mar 4, 2008 | 10:59 AM
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You can check for spark by either pulling off each plug wire (easiest to have a spare spark plug plugged into the end), lay it on the chassis, and crank. You should see spark. The other way (which is probably better for you since the car is running) is to just connect a timing light to each plug wire and see if the timing light flashes.

If there is no spark on trailing, that would cause the tach not to work. If everything is wired correctly to the coil, then the problem is usually the ignitor (trailing). Since you just replaced the engine, make sure that you have both of the 'T' shaped plugs plugged in on the distributor. Even if they look plugged in, pull them off and check the pins below. I have seen cases where the pin gets bent. The plug will look connected, but the pin is not making an electrical connection.

For the alt, it could be that you have the wrong plug plugged into it. What are the wire colors on the connector that is plugged into the alt?
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Old Mar 4, 2008 | 11:16 AM
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Thinking about it now, I did put the timing light on the trailing wires and it does not flash so that is the tach problem. I will check the conections tonight.

I will also look at the alt wire colors tonight and see if I got that right. I did mark the wiring to the alt and other stuff before I pulling the old engine out.

Thanks for all the help. I will give an update tonight.
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Old Mar 4, 2008 | 11:25 PM
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check your fuesable links... if the alt. is not charging the center one may be fried.
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Old Mar 5, 2008 | 09:02 AM
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Well the problem with the trailing and tach was one of the tabs on the ignitor was a little bent and not making good contact.

As for the alt. problem, it is working fine. The guage was sticking so was not showing the correct voltage. I tested it at the batt and it was charging fine. The guage slowly started working right after about 10 min of running.

Thanks for the help.
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Old Mar 5, 2008 | 09:08 AM
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Good to hear.
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