computer controlled alternator with MS2
Moderators: jsmcortina, muythaibxr
computer controlled alternator with MS2
Hi All
On my ford 4.6, the PCM controlled the alternator. As far as I can tell, one of the 3 pins went to the indicator light on the dash, one went to the “sense” line, connected to 12v, and one went to the PCM.
What is the function of the PCM line, and can I just lift it and not worry? I think I blew out the logic circuitry on my alternator, and I ran with the 3 pin plug unconnected. The battery is over-charging, and I need to rev the engine a little upon start up to kick in the alternator..
Any thoughts?
Thanks
olaaf
On my ford 4.6, the PCM controlled the alternator. As far as I can tell, one of the 3 pins went to the indicator light on the dash, one went to the “sense” line, connected to 12v, and one went to the PCM.
What is the function of the PCM line, and can I just lift it and not worry? I think I blew out the logic circuitry on my alternator, and I ran with the 3 pin plug unconnected. The battery is over-charging, and I need to rev the engine a little upon start up to kick in the alternator..
Any thoughts?
Thanks
olaaf
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Re: computer controlled alternator with MS2
I've seen several different ways of doing this. On some cars, the ECU just switches the voltage regulator from high to low voltage mode. On others, it directly controls the alternator field winding.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: computer controlled alternator with MS2
Hi matt
What do you generally recommend people to do with PCM controlled alternators?
thanks
olaaf
What do you generally recommend people to do with PCM controlled alternators?
thanks
olaaf
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Re: computer controlled alternator with MS2
I think it depends on how the alternator functions. That will determine how to control it. Sometimes the wiring diagram will show the internal parts of the alternator. That will help.olaaf wrote:Hi matt
What do you generally recommend people to do with PCM controlled alternators?
thanks
olaaf
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
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Re: computer controlled alternator with MS2
Precisely - you need to figure out what the PCM is doing to control the alternator first.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: computer controlled alternator with MS2
That may be your problem right there. Regardless of what you do with the other two wires, do NOT run with the "sense" line disconnected! When you do that, the alternator may think the system is getting 0 volts and increase its output to compensate... thus overcharging the battery.olaaf wrote:I think I blew out the logic circuitry on my alternator, and I ran with the 3 pin plug unconnected. The battery is over-charging, and I need to rev the engine a little upon start up to kick in the alternator..
I'd try connecting the sense line to (in order of preference) the +12 "main junction point" if your car has one, or the alternator's output terminal, or the battery. Connect an indicator light to the light terminal and the ignition +12 (that'll eliminate having to rev the engine to get the alternator going), and go from there.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking
Be alert! America needs more lerts.
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking
Be alert! America needs more lerts.
Re: computer controlled alternator with MS2
Here's some info about the Ford alternator control: http://www.napaechlin.com/Ford-PCM+Cont ... ntent.aspx
http://ww2.justanswer.com/uploads/djenn ... 48_alt.png
The two control lines are the voltage command from the PCM to the alternator (voltage encoded by frequency or PWM), and alternator reporting its electrical load with a PWM signal. There's no provision even in MS3 to output an arbitrary frequency, is there?
http://ww2.justanswer.com/uploads/djenn ... 48_alt.png
The two control lines are the voltage command from the PCM to the alternator (voltage encoded by frequency or PWM), and alternator reporting its electrical load with a PWM signal. There's no provision even in MS3 to output an arbitrary frequency, is there?
Re: computer controlled alternator with MS2
I am using the following alternator from a Ford Focus TDci Mk1:
F03093 / C870 / 12A690 / O5 GENERATOR
ACTUAL PART NOS
MS1022118070
A115IM
?M5T1030[0/O]BC
MAGNETI MARELLI
It has the following Smart Charge pins:
pin 1 4-EB6 (GY) DATA LINK, BUS POSITIVE - ALT COM (alt command?) - Gray Wire
pin 2 5-EB6 (BU) DATA LINK, BUS NEGATIVE - ALT MON (alt monitor?) - Blue Wire
pin 3 30-BA10 (RD) PERM POSITIVE
Would I be correct in thinking that if I left pin 2 open (because I am not using a Ford Smart Charge Powertrain Control Module), connected pin 3 to permanent +12V (as per every Focus wiring diagram I've come across), and then connected pin 1 (which would be the alternator command wire from a Ford PCM) to a stable permanent +12V also, the alternator would would read the stable +12V on the command input as a 100% Pulse Width Modulation signal and assume a Ford Smart Charge Powertrain Control Module was telling it to output maximum power possible at all times..
I'm aware that if that *is* how it works, then in a normal, standard realworld battery charging situation there would be allsorts of attendant problems with doing this such as boiling the battery etc. I'd just like to try and find out if I'm understanding correctly the practicalities of how this Ford alternator control system works.
Is it more complicated than just calling pure +12V a valid 100% PWM signal? Is the valid signal a different voltage such as say 5V, is there a particular range amplitude and frequency of PWM pulses at play etc?
Can anyone point me to any datasheets for the Ford alternator data specifications / parameters / protocol descriptions?
F03093 / C870 / 12A690 / O5 GENERATOR
ACTUAL PART NOS
MS1022118070
A115IM
?M5T1030[0/O]BC
MAGNETI MARELLI
It has the following Smart Charge pins:
pin 1 4-EB6 (GY) DATA LINK, BUS POSITIVE - ALT COM (alt command?) - Gray Wire
pin 2 5-EB6 (BU) DATA LINK, BUS NEGATIVE - ALT MON (alt monitor?) - Blue Wire
pin 3 30-BA10 (RD) PERM POSITIVE
Would I be correct in thinking that if I left pin 2 open (because I am not using a Ford Smart Charge Powertrain Control Module), connected pin 3 to permanent +12V (as per every Focus wiring diagram I've come across), and then connected pin 1 (which would be the alternator command wire from a Ford PCM) to a stable permanent +12V also, the alternator would would read the stable +12V on the command input as a 100% Pulse Width Modulation signal and assume a Ford Smart Charge Powertrain Control Module was telling it to output maximum power possible at all times..
I'm aware that if that *is* how it works, then in a normal, standard realworld battery charging situation there would be allsorts of attendant problems with doing this such as boiling the battery etc. I'd just like to try and find out if I'm understanding correctly the practicalities of how this Ford alternator control system works.
Is it more complicated than just calling pure +12V a valid 100% PWM signal? Is the valid signal a different voltage such as say 5V, is there a particular range amplitude and frequency of PWM pulses at play etc?
Can anyone point me to any datasheets for the Ford alternator data specifications / parameters / protocol descriptions?
Re: computer controlled alternator with MS2
Apologies for the potential double post. Upon a little more searching I found some great relevant info here: http://www.msextra.com/forums/viewtopic ... 31&t=58716