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Alternator/Voltage issues

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Old 02-02-2016, 06:45 PM
  #21  
Bill Curlee
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Originally Posted by CaliSStoZ06
So I installed the old alt back and all was fine for a week. It rained pretty good here lastnight and I went to go start the car this morning and got one click and nothing. Lights and radio work just fine.
Was your battery dead, OR would it just not crank????

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Old 02-03-2016, 11:43 PM
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Originally Posted by Bill Curlee
1. The RED (13) wire is the BATT wire. That wire is connected to the battery THROUGH the bolt on the starter SOLENOID main power input terminal. IF,,,,,,,, that solenoid terminal is LOOSE/CORRODED/BROKEN/BURNT,,, you will have **** poor fluctuating or NO charging voltages
The connections at the starter are the first thing to check with a fluctuating voltage. Don't just snug the bolt up. Take it apart and clean the terminal rings so they're nice and shiny then put it back together.


Originally Posted by Bill Curlee
3. What do you THINK the charging voltage should be??? There is NO set value. Sometimes it can be at 13.8 and sometimes it can be at 14.5. It all depends on what the regulator and PCM determines what it needs to be.

The PCM has NO control over the charging voltage. Pretty sad seeing this come from you Bill.

The voltage regulator has a temperature compensation circuit in it. So, the voltage will drop a bit when the alternator gets hot. This circuit is supposed to mimic the battery charging requirements. You charge a battery at a lower voltage when it's hotter and at a higher voltage when it's colder. It doesn't work the greatest since the battery and alternator are in two different locations, but it's the only thing that causes the regulator to vary the charging voltage.
Old 02-04-2016, 10:52 PM
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CaliSStoZ06
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Default Alternator Question

Originally Posted by lionelhutz
The connections at the starter are the first thing to check with a fluctuating voltage. Don't just snug the bolt up. Take it apart and clean the terminal rings so they're nice and shiny then put it back together.





The PCM has NO control over the charging voltage. Pretty sad seeing this come from you Bill.

The voltage regulator has a temperature compensation circuit in it. So, the voltage will drop a bit when the alternator gets hot. This circuit is supposed to mimic the battery charging requirements. You charge a battery at a lower voltage when it's hotter and at a higher voltage when it's colder. It doesn't work the greatest since the battery and alternator are in two different locations, but it's the only thing that causes the regulator to vary the charging voltage.
checked the voltage at the alternator was 14.4 so the DIC must be inaccurate, because it was reading less. Car started today just fine. Maybe sticking solenoid? I'm going to put the car on a lift next week and check starter and grounds

Last edited by CaliSStoZ06; 02-04-2016 at 10:53 PM.
Old 02-04-2016, 11:51 PM
  #24  
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Originally Posted by CaliSStoZ06
checked the voltage at the alternator was 14.4 so the DIC must be inaccurate, because it was reading less...
As suggested above on this post, now that you have the voltage measured directly at the alternator you need to take a reading directly at the battery. Both readings should be the same, or very close, otherwise the connection at the starter is not good.
Old 02-05-2016, 02:06 PM
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Bill Curlee
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Originally Posted by lionelhutz
The connections at the starter are the first thing to check with a fluctuating voltage. Don't just snug the bolt up. Take it apart and clean the terminal rings so they're nice and shiny then put it back together.





The PCM has NO control over the charging voltage. Pretty sad seeing this come from you Bill.

The voltage regulator has a temperature compensation circuit in it. So, the voltage will drop a bit when the alternator gets hot. This circuit is supposed to mimic the battery charging requirements. You charge a battery at a lower voltage when it's hotter and at a higher voltage when it's colder. It doesn't work the greatest since the battery and alternator are in two different locations, but it's the only thing that causes the regulator to vary the charging voltage.

SO,,,,, The PCM controlling the DUTY CYCLE to the regulator has nothing to do with the CHARGING SYSTEM. I should have stated Voltage & Current. The Duty Cycle helps regulate charge current.. and that comes from the PCM.
Old 02-05-2016, 06:52 PM
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Originally Posted by Bill Curlee
SO,,,,, The PCM controlling the DUTY CYCLE to the regulator has nothing to do with the CHARGING SYSTEM. I should have stated Voltage & Current. The Duty Cycle helps regulate charge current.. and that comes from the PCM.

No, it does not. The duty cycle signal goes from the alternator to the PCM. It is not a PCM control signal.
Old 02-06-2016, 06:48 AM
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Originally Posted by lionelhutz
No, it does not. The duty cycle signal goes from the alternator to the PCM. It is not a PCM control signal.



Mr. Sam



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