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Old 03-29-2006, 05:00 PM
  #1  
MAC67stang
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Default not charging

So I am lost, looking for a little advice.

I have a 67 289 coupe.

There is a problem with the charging system. The alternator, battery, starter solenoid, and voltage regulator are all 3 months old. I took the alternator out and had it checked at checkers, and it tested out fine. I replaced the VR with another new one. Added another block to body ground. retaped some frayed ground wires. With the car running it only puts out about 10.5-11 volts at both the battery and the alternator. I jumped A-F on the VR and it increases about 1 volt to about 11.5V.

I have also done the following procedure:
Disconnect the battery and get out the ohmmeter. Check the continuity of the following circuits:

1. Alternator output (large) terminal to battery positive.
2. Alternator field (small) terminal to regulator plug "F" connector.
3. Alternator case to battery negative (checks ground).

These all checked out fine

Reconnect battery and check for:

1. Battery voltage at the regulator A+ (in plug). 11.3

Turn Ignition Key on and check for:

1. Battery voltage (or within a volt or two) at the regulator I terminal. 10.5

If the above don't check out, then open circuit needs repair. If okay, then:

1. Connect a voltmeter across the battery terminals and measure voltage. Should be between 12.5 to 13.5 volts. Start engine and run at a minimum of 1100rpm. Voltage should be around 14.5 to 15.0 volts. If so, you are good to go. If not, disconnect the plug to the regulator and temporarily connect the A+ and F terminals in the regulator plug together while measuring battery voltage. Do not jump for more than 10 seconds as you can overheat the alternator. The voltage will typically be 15-16 volts. Doing this has bypassed the regulator and "full-fielded" the alternator causing max output.

If everything else is cool and the voltage still did not go up, you have a bad alternator. If the voltage went up you have a bad regulator.

Any ideas? I am stumped. Based on the test above it seems like it would be a bad alternator, but I watched checkers test it and it passed putting out 13.6V i believe it was.
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Old 03-29-2006, 05:17 PM
  #2  
slickman
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Default RE: not charging

Looks like you're on the right track and did allot of testing. This would lead me to think the alternator is bad in spite of what the testing showed. They may have only tested it with no load..

ORIGINAL: MAC67stang

So I am lost, looking for a little advice.

I have a 67 289 coupe.

There is a problem with the charging system. The alternator, battery, starter solenoid, and voltage regulator are all 3 months old. I took the alternator out and had it checked at checkers, and it tested out fine. I replaced the VR with another new one. Added another block to body ground. retaped some frayed ground wires. With the car running it only puts out about 10.5-11 volts at both the battery and the alternator. I jumped A-F on the VR and it increases about 1 volt to about 11.5V.

I have also done the following procedure:
Disconnect the battery and get out the ohmmeter. Check the continuity of the following circuits:

1. Alternator output (large) terminal to battery positive.
2. Alternator field (small) terminal to regulator plug "F" connector.
3. Alternator case to battery negative (checks ground).

These all checked out fine

Reconnect battery and check for:

1. Battery voltage at the regulator A+ (in plug). 11.3

Turn Ignition Key on and check for:

1. Battery voltage (or within a volt or two) at the regulator I terminal. 10.5

If the above don't check out, then open circuit needs repair. If okay, then:

1. Connect a voltmeter across the battery terminals and measure voltage. Should be between 12.5 to 13.5 volts. Start engine and run at a minimum of 1100rpm. Voltage should be around 14.5 to 15.0 volts. If so, you are good to go. If not, disconnect the plug to the regulator and temporarily connect the A+ and F terminals in the regulator plug together while measuring battery voltage. Do not jump for more than 10 seconds as you can overheat the alternator. The voltage will typically be 15-16 volts. Doing this has bypassed the regulator and "full-fielded" the alternator causing max output.

If everything else is cool and the voltage still did not go up, you have a bad alternator. If the voltage went up you have a bad regulator.

Any ideas? I am stumped. Based on the test above it seems like it would be a bad alternator, but I watched checkers test it and it passed putting out 13.6V i believe it was.
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Old 03-29-2006, 05:22 PM
  #3  
Derf00
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Default RE: not charging


ORIGINAL: MAC67stang

So I am lost, looking for a little advice.

I have a 67 289 coupe.

There is a problem with the charging system. The alternator, battery, starter solenoid, and voltage regulator are all 3 months old. I took the alternator out and had it checked at checkers, and it tested out fine. I replaced the VR with another new one. Added another block to body ground. retaped some frayed ground wires. With the car running it only puts out about 10.5-11 volts at both the battery and the alternator. I jumped A-F on the VR and it increases about 1 volt to about 11.5V.

I have also done the following procedure:
Disconnect the battery and get out the ohmmeter. Check the continuity of the following circuits:

1. Alternator output (large) terminal to battery positive.
2. Alternator field (small) terminal to regulator plug "F" connector.
3. Alternator case to battery negative (checks ground).

These all checked out fine

Reconnect battery and check for:

1. Battery voltage at the regulator A+ (in plug). 11.3

Turn Ignition Key on and check for:

1. Battery voltage (or within a volt or two) at the regulator I terminal. 10.5

If the above don't check out, then open circuit needs repair. If okay, then:

1. Connect a voltmeter across the battery terminals and measure voltage. Should be between 12.5 to 13.5 volts. Start engine and run at a minimum of 1100rpm. Voltage should be around 14.5 to 15.0 volts. If so, you are good to go. If not, disconnect the plug to the regulator and temporarily connect the A+ and F terminals in the regulator plug together while measuring battery voltage. Do not jump for more than 10 seconds as you can overheat the alternator. The voltage will typically be 15-16 volts. Doing this has bypassed the regulator and "full-fielded" the alternator causing max output.

If everything else is cool and the voltage still did not go up, you have a bad alternator. If the voltage went up you have a bad regulator.

Any ideas? I am stumped. Based on the test above it seems like it would be a bad alternator, but I watched checkers test it and it passed putting out 13.6V i believe it was.
Looks like you've done everything but replace the cables themselves. Never underestimate the capillary action that corrosion does. In other words, just because the outside of the cable looks good/clean, doesn't mean corrosion hasn't made its way into the cable itself. Sounds like you got too much resistance somewhere.
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Old 03-29-2006, 05:23 PM
  #4  
MAC67stang
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Default RE: not charging

Oh yeah, it has new cables too!
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Old 03-29-2006, 07:00 PM
  #5  
Soaring
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Default RE: not charging

Replace those frayed ground wires.
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Old 03-29-2006, 08:41 PM
  #6  
MAC67stang
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Default RE: not charging

Just put another new alternator in and still a no go. I guess I am going to try jumping the ground with cables or something and maybe try another battery, but still open to suggestions. Thanks for all the help so far.

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Old 03-29-2006, 09:18 PM
  #7  
dawtips
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Default RE: not charging

Maybe aliens have messed with both our electrical systems.
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Old 03-30-2006, 02:03 AM
  #8  
67t5ponycoupe
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Default RE: not charging

sounds like you know more about it than anyone here will. I can only offer one sugestion. Measure the continuity from the engine block to the chasis and from the altenator to the grounding point where the regulator mounts. You may find some bad grounds. A good ground should read less than one ohm. The case of the regulator also must be grounded well. These could cause an undervoltage condition.
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Old 03-30-2006, 06:42 PM
  #9  
MAC67stang
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Default RE: not charging

So I replaced the ground and power cable to the battery, even though they looked fairly new, and bam - it is working. Hopefully that was the problem and it was not a short that I just moved in the harness. We'll see how it goes. Thanks for all the help and ideas!
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