Factory camaro alternator question
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
Originally Posted by Dave_62
Just for clarification, does the field terminal have to be connected to 12V for the Corvette alt to work, or just the lamp terminal like on the F-body alt? I have a Corvette alt for my swap with a F-body harness and wanted to wire it right the first time. John, thanks for trolling the boards and keeping us all straight. 
The field wire can be left out with no change in the function of the alternator. It was only used in some applications as an internal diagnostic to determine if the alternator is functioning properly.
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Last edited by Speartech; Dec 31, 2013 at 09:30 AM. Reason: Updating old post with more accurate info.
Originally Posted by Speartech
I've always wired up the field lead when using the Vette alternator, so I'm not sure what it would do if you didn't. It's a different voltage regulator in the Vette alternator so I would assume you need to wire the field in for proper operation. You could tap into the purge canister power lead (it's close by) for a switched 12 volt source.
Sounds good to me. I'll do it that way. Thanks John!
Im a bit confused...
Do I need this resistor to keep from blowing a 2000 alternator? I just pluged the plug from my wiring harness directly into my alternator, and everything works fine as far as I know....
-Jason
Do I need this resistor to keep from blowing a 2000 alternator? I just pluged the plug from my wiring harness directly into my alternator, and everything works fine as far as I know....
-Jason
Teching In
Joined: Jun 2006
Posts: 6
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hey slow 346, can you explain how you did the one wire hookup. I have a corvette stock alt in a 69 camaro with the painless wiring kit. car starts but battery doesn't hold charge. I don't have the plug in switch from factory so can I get the alt to work without that factory plug in since I am not running a computer on the ls1 as it is a carb setup?
This thread told me everything I need to know to wire up a Camaro alternator in a car with no PCM!
A couple of other points to make. The B terminal is also the voltage sensing wire for the regulator, so it is a good idea to have it come all the way out to the fuse box. It would be easy to hook the 500 ohm resistor to the output lug of the alternator, but then the regulator would be regulating the voltage there rather than at the fuse box.
Also I would think an LED could be used if it is connected in series with the resistor. With a 500 ohm resistor you would need a 25-30 milliamp LED.
http://www.kpsec.freeuk.com/components/led.htm
Again thanks for the good info.
A couple of other points to make. The B terminal is also the voltage sensing wire for the regulator, so it is a good idea to have it come all the way out to the fuse box. It would be easy to hook the 500 ohm resistor to the output lug of the alternator, but then the regulator would be regulating the voltage there rather than at the fuse box.
Also I would think an LED could be used if it is connected in series with the resistor. With a 500 ohm resistor you would need a 25-30 milliamp LED.
http://www.kpsec.freeuk.com/components/led.htm
Again thanks for the good info.
TECH Apprentice
Joined: Oct 2005
Posts: 320
Likes: 0
From: Norwalk, CT
I learned from experience that you need that resistor or a bulb in the circuit. When I rewired my car I ran 12v thru a regular wire. On a road test I glanced over at the laptop and noticed overvoltage faults. Turns out it was charging at something like 20v! I thought I could drive it home because I was only 2 miles away, but when I got back and opened the battery box... 
One exploded optima battery and a ruined brand new rear carpet set as well as staining the aluminum battery box.
I will never make that mistake again!!!!!
One exploded optima battery and a ruined brand new rear carpet set as well as staining the aluminum battery box.
I will never make that mistake again!!!!!
Staging Lane
Joined: Oct 2004
Posts: 98
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From: Near the start of the California gold rush
One additional thing I found after a bunch of beating head against the wall. I kept getting the DTC for F wire failure.
Replaced the battery (an old Optima) and once you rev the engine above 2,500 prm, the DTC fault doesn't return.
Replaced the battery (an old Optima) and once you rev the engine above 2,500 prm, the DTC fault doesn't return.
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Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
That will work just fine. I checked the alldata diagrams for a 98 and it is actually listed as 470 ohms so this will also work http://www.radioshack.com/product/in...tId=2062320&cp
There really is not much of a voltage difference between the two so either one is fine.
There really is not much of a voltage difference between the two so either one is fine.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Originally Posted by Speartech
The Corvette alternator is a little different in that it also brings out the FIELD terminal (terminal C). The FIELD terminal DOES go directly to a switched ignition 12 volts. So the lamp terminal (terminal B) would be wired as described in the above reply I made, and the field would be wired directly to the ignition switch.
Teching In
Joined: Feb 2006
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Corvette alternator with F-Body Harness
Originally Posted by Speartech
I've always wired up the field lead when using the Vette alternator, so I'm not sure what it would do if you didn't. It's a different voltage regulator in the Vette alternator so I would assume you need to wire the field in for proper operation. You could tap into the purge canister power lead (it's close by) for a switched 12 volt source.
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
Yes, that's correct. I don't know if you need the "D" to the battery or not. I guess it depends on what model year your alternator is for. Most of the alternators use what is called an "internal sense" for voltage control so there is no connection at D, but I see some of the newer models are going to an external sense and actually running "D" to the battery.
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Teching In
Joined: Feb 2006
Posts: 36
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Originally Posted by Speartech
Yes, that's correct. I don't know if you need the "D" to the battery or not. I guess it depends on what model year your alternator is for. Most of the alternators use what is called an "internal sense" for voltage control so there is no connection at D, but I see some of the newer models are going to an external sense and actually running "D" to the battery.
Teching In
Joined: Feb 2006
Posts: 36
Likes: 0
Originally Posted by Speartech
Yes, that's correct. I don't know if you need the "D" to the battery or not. I guess it depends on what model year your alternator is for. Most of the alternators use what is called an "internal sense" for voltage control so there is no connection at D, but I see some of the newer models are going to an external sense and actually running "D" to the battery.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Originally Posted by lechner80
John will I still need a resistor in the red wire from the F-Body PCM to the Vette Alt; or is this handled by the PCM or the factory harness. Thanks John L.
Alternator- rebuild or replace? On my LT1/280Z swap, the CS144 alternator was wired in to a +12V source with ignition on w/o the resistor and was not charging. I added the 470 ohm Radio Shack resistor in this line and it still is not charging. Of course, this alternator came with another motor I had bought a while ago so I don't know if it was any good to start with.
When this happens, what part of the alternator is damaged? The rectifier or voltage regulator or something else?
Is it worthwhile to rebuild it (complete kit about $50)?
I think I have this figured out for my Toyota swap (CS130 alternator)- the charge light wire is reversed polarity from the GM setup, but I can handle that with a relay to reverse the polarity.
When this happens, what part of the alternator is damaged? The rectifier or voltage regulator or something else?
Is it worthwhile to rebuild it (complete kit about $50)?
I think I have this figured out for my Toyota swap (CS130 alternator)- the charge light wire is reversed polarity from the GM setup, but I can handle that with a relay to reverse the polarity.
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
It's the voltage regulator that is damaged from it.
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com