Alternator/Voltage issues
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
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 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.
Thread Starter
Instructor
Joined: Feb 2008
Posts: 114
Likes: 0
From: elk grove california
Alternator Question
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.
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.
Last edited by CaliSStoZ06; Feb 4, 2016 at 10:53 PM.
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
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.
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.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
No, it does not. The duty cycle signal goes from the alternator to the PCM. It is not a PCM control signal.
