FD ALT~Need quick help!!
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From: Maryland, 21794
FD ALT~Need quick help!!
Ok, just pulled my FC alt, it has one black wire w/ a white stripe, and one white wire w/ a black stripe. The FD alt has a green wire, and a green wire with a black stripe. Which goes to which? This is for the new plug to adapt FC=>FD alt. Help quick please!
Edit* whoops, the FD has green wire, and green w/ WHITE stripe(tracer)
Edit* whoops, the FD has green wire, and green w/ WHITE stripe(tracer)
Last edited by adrock3217; Aug 20, 2005 at 01:17 PM.
You're gonna need more than just the plug to install it.
S6 alternators are load sensing and if you just plug it straight in with that plug then you're just going to burn out your regulator and drain your battery whenever it sits. You need to make sure it's seeing a load signal even when the car is off. Search for "FD alternator install" and you should find a writeup on it.
S6 alternators are load sensing and if you just plug it straight in with that plug then you're just going to burn out your regulator and drain your battery whenever it sits. You need to make sure it's seeing a load signal even when the car is off. Search for "FD alternator install" and you should find a writeup on it.
https://www.rx7club.com/forum/showthread.php?t=363910 <--- Compliements of SilverRotor.
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Boost in..Apex seals out.
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From: Maryland, 21794
From the Silverrotor post :
Now..a little thing from me. I am not..electronically capable. I need pictures..heh..
I attached a pic including all the plugs, alts, and wiring. I just need a step by step way to plug it all up correctly, without any fancy tech. words, heh heh
How do I wire In my Harness Plug?
As quoted with permission from KYPREO (thank you again!):
s4 and earlier alt's are a L/R type alternator. the regulator is switched via ignition, usually through a check relay.
s5 and later alternators are a L/S type alternator. the regulator is always on, as the "s" terminal is connected to the battery positive.
Now, when you put a series 5 or FD alternator into a series 4 or earlier chassis and simply trim the old connector off and adapt it, is that the alternator expects to see 12V+ with the ignition off, but it actually sees 0V, as the ignition is off.
if you have a series 4 or earlier Mazda, is eliminate the old "r" wire, and run a fresh wire from a constant battery positive source.
I have a series 6 alternator on my Series 3 Rx-7 (australian delivered 1985 model), and I simply used the old plug, soldered the L/dash warning light wire on, then ran a new wire from a battery positive source and soldered that to the "s" wire on the s6 plug.
SIMPLE!
If you look at the factory service manual under the "engine electrical system" section of series 4 and series 5 rx-7s respectively, you will find that the wiring schematic in the alternator section shows exactly what I explained above.
Download the factory service manuals on this website for both series 4 and series 5.
Look into section 5: engine electrical system.
Go to Alternator.
Look at the schematic for series 4 and series 5 alternators respectively.
series 4 has a "T" plug. the horizontal part of the "t" is the "R" terminal. On the schematic it shows this wire going to the ignition circuit
Terminate this wire - you don't need it.
Keep the wire connected to the vertical part of the T, which is the "L" terminal (L is for warning light - it goes to the dash). This is the same for series 4 and 5.
Now, look at the schematic for the series 5 alternator. Look at the two terminals on the alternator, it should look like what is represented below - the horizontal line represents where the clip goes.
_
| |
S L
If you are looking at the front of the appropriate plug, it will be opposite.
Connect a wire from the terminal S to a constant battery positive source. Connect the exisiting s4 "L" wire to the L terminal.
As quoted with permission from KYPREO (thank you again!):
s4 and earlier alt's are a L/R type alternator. the regulator is switched via ignition, usually through a check relay.
s5 and later alternators are a L/S type alternator. the regulator is always on, as the "s" terminal is connected to the battery positive.
Now, when you put a series 5 or FD alternator into a series 4 or earlier chassis and simply trim the old connector off and adapt it, is that the alternator expects to see 12V+ with the ignition off, but it actually sees 0V, as the ignition is off.
if you have a series 4 or earlier Mazda, is eliminate the old "r" wire, and run a fresh wire from a constant battery positive source.
I have a series 6 alternator on my Series 3 Rx-7 (australian delivered 1985 model), and I simply used the old plug, soldered the L/dash warning light wire on, then ran a new wire from a battery positive source and soldered that to the "s" wire on the s6 plug.
SIMPLE!
If you look at the factory service manual under the "engine electrical system" section of series 4 and series 5 rx-7s respectively, you will find that the wiring schematic in the alternator section shows exactly what I explained above.
Download the factory service manuals on this website for both series 4 and series 5.
Look into section 5: engine electrical system.
Go to Alternator.
Look at the schematic for series 4 and series 5 alternators respectively.
series 4 has a "T" plug. the horizontal part of the "t" is the "R" terminal. On the schematic it shows this wire going to the ignition circuit
Terminate this wire - you don't need it.
Keep the wire connected to the vertical part of the T, which is the "L" terminal (L is for warning light - it goes to the dash). This is the same for series 4 and 5.
Now, look at the schematic for the series 5 alternator. Look at the two terminals on the alternator, it should look like what is represented below - the horizontal line represents where the clip goes.
_
| |
S L
If you are looking at the front of the appropriate plug, it will be opposite.
Connect a wire from the terminal S to a constant battery positive source. Connect the exisiting s4 "L" wire to the L terminal.
I attached a pic including all the plugs, alts, and wiring. I just need a step by step way to plug it all up correctly, without any fancy tech. words, heh heh
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adrock3217, a common fault one endures when Installing a FD Alt when supplied from me Is to follow the colour scheme with the supplied Harness Plug. Keep In mind that It Is a generic one, thus the colours coming out of the plug will (could) be different from another one.
When colours are referred to - always use the stock harness side.
When colours are referred to - always use the stock harness side.
With you having a s4 (86-88) the wiring Is as follows:
*blackwire/white stripe (R terminal) eliminate this wire by taping up the end. I used shrink wrap than black electrical tape.
*white wire/black stripe (L terminal) connects to the L terminal of the FD Plug.
*connect S terminal from FD Plug goes Into a 12v positive source, I used the Battery.
I highly recommend you solder, shrink tube all connections for permanent reliability.
Let me know If you have any additional questions.
*blackwire/white stripe (R terminal) eliminate this wire by taping up the end. I used shrink wrap than black electrical tape.
*white wire/black stripe (L terminal) connects to the L terminal of the FD Plug.
*connect S terminal from FD Plug goes Into a 12v positive source, I used the Battery.
I highly recommend you solder, shrink tube all connections for permanent reliability.
Let me know If you have any additional questions.
Yeah, dDuB to the rescue. 
Quite honestly, I thought you have had read my thread already - with this schematic being In there.
How did It go? Are you noticing your windows going up any faster? Better Idle?
Let us know please.
Quite honestly, I thought you have had read my thread already - with this schematic being In there.
How did It go? Are you noticing your windows going up any faster? Better Idle?
Let us know please.
'86 N/A Phone Dials
Joined: Mar 2005
Posts: 360
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From: Farmington, Minnesota
I have a quick question as I just purchased an FD alternator from silverrotor.
The diagram that was posted by dDub is great information, but would this work even better?...
Since, in parallel circuits, voltage is constant throughout every component, then the battery lead and constant lead need to be connected to the battery (12.66V, or 14.5V at Idle). The diagram suggests running 2 wires to the battery. One from the B terminal of the Alt. and one from the voltage regulator.
Here is the diagram again:
Can you just run a small length of wire from the S terminal to the B terminal and then have one long wire running to the Battery+? Here's what I mean:
The diagram that was posted by dDub is great information, but would this work even better?...
Since, in parallel circuits, voltage is constant throughout every component, then the battery lead and constant lead need to be connected to the battery (12.66V, or 14.5V at Idle). The diagram suggests running 2 wires to the battery. One from the B terminal of the Alt. and one from the voltage regulator.
Here is the diagram again:
Can you just run a small length of wire from the S terminal to the B terminal and then have one long wire running to the Battery+? Here's what I mean:
Registered 7 User
Joined: Jul 2005
Posts: 135
Likes: 0
From: Kitchener, Ont, Ca
I'm no expert but I'd say no because by the looks of things the S terminal is the alts input of power and the B is the output and you want to keep them separate to the alt, so it can have the power come from battery smaller line (because it needs little power there) on one line and leave with the other (the thicker one so your battery gets the most power) so you don't fry the alt…..oh and if you want a better electrical system yet upgrade the big three (car audio thing). The battery (-) to the Battery negative to chassis, the alts (+) to battery, and Engine to Chassis (-)
'86 N/A Phone Dials
Joined: Mar 2005
Posts: 360
Likes: 0
From: Farmington, Minnesota
Well, you didn't really convince me. Ohm's Law convinces me. In parallel circuits, such as the one in the diagram above, voltage is the same. So, I would ASSUME, Instead of running 2 wires that were 3-4 feet or whatever, just run one wire that was 3-4 feet, and one wire that was about 3-4 inches from the regulator to the B terminal.
In DC circuit theory, they are the same exact circuit. The latter having the advantage of less wire. A savings of Cost and Space. But if there is something I am not considering, please post.
In DC circuit theory, they are the same exact circuit. The latter having the advantage of less wire. A savings of Cost and Space. But if there is something I am not considering, please post.
Registered 7 User
Joined: Jul 2005
Posts: 135
Likes: 0
From: Kitchener, Ont, Ca
Well the only problem I could see is a fuse/Breaker but as long as you have it on that it would be fine but I know when I get my Fd alt in I won't be going that way (it's a pain to splicing into a 1/0 gauge wire)
Originally Posted by Needa13b
Well, you didn't really convince me. Ohm's Law convinces me. In parallel circuits, such as the one in the diagram above, voltage is the same. So, I would ASSUME, Instead of running 2 wires that were 3-4 feet or whatever, just run one wire that was 3-4 feet, and one wire that was about 3-4 inches from the regulator to the B terminal.
In DC circuit theory, they are the same exact circuit. The latter having the advantage of less wire. A savings of Cost and Space. But if there is something I am not considering, please post.
In DC circuit theory, they are the same exact circuit. The latter having the advantage of less wire. A savings of Cost and Space. But if there is something I am not considering, please post.
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