Let's figure out alternator wiring, once and for all! HELP!

[bobafett]

Okay guys, I am going to need to figure out the alternator wiring sooner than later.

My car was EFI, so I have the following wires coming off of the alt:

Obviously the large white wire that connects to a post using a ring terminal. This wire goes to the fuse box.

Next we have the green connector that has 4 wires.

Bl/Y = Black/Yellow
W/R = White/Red
W/Bu = White/Blue
W/G = White/Green

I need to figure out EXACTLY what these wires do, and how I need to use them.

For those that don't know I eliminated the stock fuse panel, and I am running a standalone 'painless' race panel. FYI it is not actually painless, this is a huge fucking PITA!

Here is what I can tell from my FSM...

Black/Yellow = I think this is stuff that gets activated when the key is at the 2nd click
- Hits all kinds of shit
- Cooling Fan Timer
- Main Relay and Fuel Pump
- Fuel Pump Cut-Off Relay
- Ignition Coil
- Condenser (??)
- Igniter Unit
- Something about Speed Sensors (WTF I thought we had cable speedo, and no electronic VSS (or are they talking about engine speed?))
- IG1 (Ignition Switch Position 1??) Does that mean that the first ignition switch position activates the things above on the list?

White/Red = no idea but I think this went to the ECU
- Goes to the ACGF on both EFI and Carbed models
- what the shit is the ACGF????

White/Blue = guessing that this is the wire that tells the something-or-other when to show the battery light on our dash.
- goes to choke/heater which then grounds
- meets up with the Black/Yellow and has to do with the 'Charge Warning Light' somehow
- Goes to 'Integrated Unit' (don't know what it does there - maybe lights the dash indicator?)
- Goes into 'EFE Unit' (WTF IS THAT??) which then grounds

White/Green = no idea?
- Cooling Fan Relay
- Cooling Fan Motor
- Condenser Fan Motor (Carbed Cars)
- Rear Window Defroster
- Main Relay eventually?

Anyway, if anybody can help me figure out exactly what these wires actually do, and which ones I need to use for the alternator to work properly, it would be greatly appreciated.

I have an accord service manual, and I got the info from the diagrams in the back, but I am terrible at reading these diagrams so my assumptions are probably shit.

Help me out here guys!

Thanks,
Chris

[bobafett]

http://www.pauldesign.ru/honda/shopmanual/engine_electrical.zip

If you download this guide and look at image 24-3 it is different than my manual, but simpler and a bit easier to read.

Ugh, if I go to 24-3 in my manual there is also a MORE simple breakdown. Still doesn't translate into what I can eliminate, and what I NEED, but it is easier to read and doesn't have all the BS!

Here's the AWESOME instructions for my fuse panel. They are about as pointless as it gets! http://painlessperformance.com/Manuals/50101Instruction.pdf

[bobafett]

Okay, looking at the simplified diagram, here is my revised stab at this:

Large White Wire is called the 'B' Terminal. It originally went to the Fuse Box.
- it looks like this is the wire that connects to the battery power in the fuse panel
- the power to the ignition switch is also on this circuit.

White/Blue Wire = 'L' wire. I assume this means LIGHT, because it is the warning light in the other diagrams. Seems to connect to the Black/Yellow, my guess is it checks the voltage on that wire, and if it is too high/low it will trip the 'warning light'

White/Green = "S" wire. Goes to underhood relay box, FUSE 8 (10A), according to the manual, fuse 8 is the voltage regulator.

Black/Yellow = "IG" wire. goes to ignition switch, coil, condenser etc,

White/Red = "FR" wire. Goes to ECU, dunno what it does there other than the previously mentioned confusing ACGF.

Yeah so it still doesn't make any sense to me. lmao...

[Ichiban]

You forgot one: It also grounds through the case....haha!

joking, anyways...

White/Red goes to the ECU. It doesn't seem to serve any other purpose then to set a trouble code when it isn't connected.

White/Blue (Terminal "L") goes to one side of the charge light and for some reason to the oil pressure warning circuit. I believe this might have to do with the post start dummy light check. I'm betting the sole purpose of this terminal is to provide a ground to activate the charge light when something inside the voltage regulator tells it to.

Black/Yellow (Terminal IG) goes to the other side of the charge light, then off to IG 1 off the accessory switch. IG 1 feeds a whole bunch of other shit, which I don't really think is too important to this discussion. I bet the purpose of this terminal is to energize the field windings of the alternator.

White/(Blue?) (Terminal "S") Here's where our diagrams obviously differ. Mine shows it having constant power on the same circuit as the White "out" wire. My diagram also simply gives it the colour white only. Something else in there obviously needs power.

I say get an alternator off of a 79-83 Toyota pickup. The external dimensions are identical to the Honda one, but it's set up for an external voltage regulator of your choice. Each terminal on the back of the alt is for what it does inside, not some mystery purpose.

BTW "EFE" is early fuel evaporation, that stupid heated grid under the carburettor.

[bobafett]

hmm thank you very much for the suggestion of the toyota alt! that would be a major headache avoided if it bolts right in and i can figure out how to wire it!

do you know the wires that would need to be hooked up to that alt, and what they would need to go to?

thanks for your post it was very helpful!

[cygnus x-1]

You guys just about have it but here is what I know.

Just the other day rigged up an older Camry alternator (typical Denso, just like Hondas) for my Diesel Samurai conversion. I actually used the 3 wire plug for a 3g carbed Accord alternator because I had it laying around and it fit.


The big post on the alt. goes to the + side of the battery (which also goes to the fuse box). This is the main power terminal.

The "L" terminal is for light or lamp. This tells you when there is a problem with the alternator. This should connect to one side of the "batt" lamp in the dash/panel. I would probably ignore the connection to oil pressure circuit.

"IG" goes to switched ignition. This needs to have power when the ignition switch is in the "ON" position and the "START" position. This does indeed provide power for the alt. field windings.

"S" is the sense line. This helps the voltage regulator inside the alt. maintain the proper voltage. The idea is to sense the actual voltage from a more remote part of the power system. This could be connected to any positive voltage source really. The battery + terminal or the main lug on the starter would be a good choice.

The 4th one I've not seen before, and my alt. doesn't have that. But some digging around on Google says that it's some sort of timing reference line for the ECU with a designation of "FR". I don't really know what that means but if you aren't using a factory ECU I would just ignore it.


C|

[Hauntd ca3]

in theory the alt only needs two wires to work
the out put to the batt and the wire going in from the warning light circuit which the alt needs.
thats the field current that turns the armature into an electro magnet so you can generate power.
newer systems will use the ecu to control the field current so that voltage is more consistant and current is varied depending on batt condition
the ign,l and s wires are all to do with the field circuit and the other is the batt wire as we know.
and the fr wire will have some thing to do with the ecu voltage correction for all the sensors.
i'd say that you cant really eliminate any of those wires without causing some sort of problem.
talk to an auto sparky and show him/her the diagram and they would tell you if you can or not.
but i still think its unlikely you'll be able to

[bobafett]

well thats part of the problem. the car doesn't have a dash anymore, so doesn't have a battery warning light. also the standalone ecu has no interest in alternator wires, so those are no longer stock and not as easy to accommodate.

from the help you guys have provided so far, here is my plan:

large white wire = Will go to the distribution block that the battery and fuse panel also connect to. This should allow the alt to charge the battery and feed the fuse panel. No big deal there, that was the only obvious one.

black/yellow (ig) = Will connect to the IGN switch. When IGN switch is activated (mine is just a toggle) the alternator will be getting power from this wire.

white/green (s) = Will connect to some other power source (starter wire seems fine. Though there really isn't a 'remote' section of wiring in my car since I am starting from scratch. But I will give some +12V source to go back to the alternator so it knows how much voltage the system is seeing.

---------------------

If white/red (fr) goes to the ECU to make adjustments to sensor readings due to system voltage then I don't need it at all. My standalone ECU has it's own provisions to make adjustments like that.

As long as the alternator functions properly without this wire (which a carb alternator certainly does) I should be okay just not using it.

----------------------

I don't know if I will utilize a warning light (at least not right away) but if I do, I feel that connecting the white/blue wire to one side of a lamp, and the black/yellow wire to the other side of a lamp, will activate a warning lamp if the system voltage gets too screwy.

If I am reading the diagram right that is all there is to it. haha the more I think about this, the more important a warning light probably is since this system is sooooo different than stock.

Thanks for your inputs so far, they have saved my headache and hopefully got me going on the right track. I can only stare at these wiring diagrams for so long before I get totally confused.

- Chris

[cygnus x-1]

I would almost guarantee that you don't need the FR connection. Wire it up like you just said and it will work fine. You might as well have an indicator too since you have one for everything else. :D Can't have too many lights, buttons, and gauges right?

C|

[Ichiban]

Just the other day rigged up an older Camry alternator (typical Denso, just like Hondas) for my Diesel Samurai conversion. I actually used the 3 wire plug for a 3g carbed Accord alternator because I had it laying around and it fit.



"S" is the sense line. This helps the voltage regulator inside the alt. maintain the proper voltage. The idea is to sense the actual voltage from a more remote part of the power system. This could be connected to any positive voltage source really. The battery + terminal or the main lug on the starter would be a good choice.

The 4th one I've not seen before, and my alt. doesn't have that. But some digging around on Google says that it's some sort of timing reference line for the ECU with a designation of "FR". I don't really know what that means but if you aren't using a factory ECU I would just ignore it.


C|

I've actually scavenged the brushes and other parts out of a Denso for Honda alternator for my toyota. Also, the Sense line does make sense, literally. I was wondering why it would need power from another source separate from the direct battery connection, and voltage sensing was what sprung to mind.

The carb'd alternators don't have that 4th line out, so if the ECU doesn't require it, I wouldn't bother with it.

[Hauntd ca3]

if your car is efi, i dont think you will be able to delete any wiresat al.
te 3 wires that go in the plug labled S, ign and L are all part of the alt field circuit and the alt wont work properly without them.
the fr wire going to the ecu will prob be for the ecus own voltage correction purposes .
since current flow changes with voltage assuming the resistance stays the same, the ecu will
think some values are wrong unless it can correct itself if it knows the voltage and everything runs sweet as

[Hauntd ca3]

as far as a warning light goes, why not just put a small ammeter and voltmeter in the field circuit since thats pretty much all the charge light does is tell you that there is field current and voltage ofmore than 12.5 volts

[2oodoor]

sticky please
this is right on time, I want to use JDM EFI alternator in the LX since it is already bolted on the engine belt and all.

[A18A]

^cant you just swap voltage regulators?

[bobafett]

if your car is efi, i dont think you will be able to delete any wiresat al.
te 3 wires that go in the plug labled S, ign and L are all part of the alt field circuit and the alt wont work properly without them.
the fr wire going to the ecu will prob be for the ecus own voltage correction purposes .
since current flow changes with voltage assuming the resistance stays the same, the ecu will
think some values are wrong unless it can correct itself if it knows the voltage and everything runs sweet as

My ecu has a +12V source that powers it. It handles voltage correction through that one power source, it does NOT need or have provisions for an 'extra' wire that does nothing but monitor voltage.

Luckily, the other wires appear to have nothing to do with the ECU, so I think I am good to go. If I LITERALLY CAN'T get rid of the FR wire, I will just buy a carbed alt, or get a toyota one if I can verify fitment etc...

http://distributorless.com/products/tec.php
http://distributorless.com/products/tecgt.php

That is my computer, nothing even close to a stock PJ0, so it just doesn't have the same connections. Also, I have 0 of the stock accord wiring left in my car, so it's not like I can hook it up anywhere close to the 'same' way.

I think I have a handle on it, but the rest of the car's wiring is not finished so I cannot test this just yet.

[Ichiban]

the fr wire going to the ecu will prob be for the ecus own voltage correction purposes .
since current flow changes with voltage assuming the resistance stays the same, the ecu will
think some values are wrong unless it can correct itself if it knows the voltage and everything runs sweet as

You are doing a good job of ignoring everything that's been said. He has no need for the FR wire as his aftermarket ECU has NO NEED for it. What we need to know is if not having the FR wire connected affects the alternator in any way, which I am sure it does not.

[drob]

Just a possibility - on a more recent Chrysler product, the FR signal is sent from the alternator to the ECU to tell it that the field is at full voltage (100% output). This is sensed by the ECU to bump the idle speed so the alternator can output higher voltage. So FR isn't strictly required in this case. It may appear to pulse at less that 100% output, so this is the reference others talk about.

[Hauntd ca3]

chances are that since your aftermarket ecu has its own volage correction, you will be able to dump the fr wire without any hassles.
since you hav custom wiring, just wire it so it works
i dont see anything wrong with what you doing otherwise

[bobafett]

Just an update, I wired this the way I described and it works amazingly well from what I can tell. With the car running I get 14.X volts and it is VERY steady. So for anybody attempting a weird alternator setup or weird ECU setup this plan seems to work very well!

[AccordB20A]

just for the record i have used a 3 pin regulator on a efi system. meaning the white/red wire was not needed. i think all it does is steps up the idle with something in the black box when theres large load on the alternator. wont cause any error codes etc etc.

my engine loom has two plugs on it currently, a 3 pin for a carbed regulator and a 4 pin for a efi one. so if i blow an alt i can temporarily plug in a carb one until i manage to find another 4 wire reg.... since i go thru alternators like i change my pants

[bobafett]

good to know. what what i have gathered on my electromotive ecu is that if voltage drops really really low, injector pulsewidth will be shorter than intended. so the tec-gt will increase the length of the pulsewidth to compensate for the fact that at 8 volts it will need to be longer for the car to run properly.

so i assume that as long as your car is operating in a normal range of voltage, the white/red wire will not be needed, and the car will run as expected. assuming that the accord uses this wire for the same function that my aftermarket ecu does.

[lostforawhile]

the oddball wire is just a calibration wire for the ecu so it can take the voltage at the alternator and calibrate the sensor input to it. it also senses load,the carbed cars don't have this.

[lostforawhile]

ok to explain the warning lamp, when the engine is running the regulator rapidly switches the field current on and off, when it's on it's 12 volts+ when off it's ground. one side of the charge lamp is connected to 12 volts + the other to field, when it's charging, there is 12 volts+ on both sides of the lamp
and it stays off, if it quits charging, field changes to - and the lamp comes on. it's connected to the multifunction box also, to allow the oil light flasher to only work when the engine is running. on carb cars it also powers the choke heater, if the alternator quits, the choke closes. the extra wire on fi cars tells the ecu the engine is under load and the idle speed is raised

[lostforawhile]

ok white/green goes to fuse 8 in the underhood fuse box, it's hot all the time
black/yellow is power switched on with ignition
white/blue is to the lamp, when it shows a positive state it also tells other circuits the engine is running, and powers the choke in carbed cars

white/red is for FI cars and tells the ecu the status of electrical load

[lostforawhile]

since the oil pressure light was mentioned here, I'll explain it since it ties into the alternator circuit. the oil pressure switch is directly connected to the light itself, when oil pressure is low, it grounds causing the lamp to come on, that part everyone knows, it's not connected to the bulb check circuit, because as soon as you turn on the ignition, without the engine running, it's going to come on anyway. the flasher circuit for the light, is designed to detect brief drops in oil pressure you might not notice, if it detects a drop, the flasher circuit provides an additional ground to the switch, causing the lamp to flash. the circuitry is in the multifunction unit under the radio. the lamp will keep flashing until the ignition is switched off then on, to keep the lamp from flashing until the engine is running, it's tied into the alternator field control circuit, same as the charge light, when the engine is running, that wire changes state from a ground to + 12 volts, this turns off the altenator lamp and arms the flasher circuit. this change in state on the wire also tells the ecu or carb control unit that the system is charging. that oil light flasher is more technology out of their race cars, in a race car you might get a brief unnoticed oil pressure drop and not see it on the gauge, so this would flash a waning lamp until reset. they adapted it to a street car. this is the same technology used in those expensive race car warning lamps you get from places like summit. it' s a simple circuit, when there is 12 volts + on the alternator field wire, and ground from the oil lamp circuit, a transistor latches and triggers a pulsing ground output to the oil pressure warning circuit. the transistor can latch faster then the lamp can even light. simple now, but high tech in 86. it's an AND AND logic circuit

[Dr_Snooz]

Lost, put down the ETM. Put it down and get some sleep for God's sake!

[lostforawhile]

Lost, put down the ETM. Put it down and get some sleep for God's sake!

oh i knew this without the manual

[Tomisimo]

Good read, Sud I sticky this?

While we are at it, can anyone tell me, whats wrong with my alt. Alt light dont go off after the car is started, even tho it gives steady 14.5V. Its my second brand new alt and same thing happens all over again.

[lostforawhile]

Good read, Sud I sticky this?

While we are at it, can anyone tell me, whats wrong with my alt. Alt light dont go off after the car is started, even tho it gives steady 14.5V. Its my second brand new alt and same thing happens all over again.

yea go ahead, unplug the connector at the alternator and see if the light goes out, if it does it's a problem with the regulator inside of the alternator, the small white/blue wire in the plug should have 12 volts between it and ground with the engine running