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Discussion Starter · #201 · (Edited)
Yes, the voltage regulator controls the charging. But where does the 5v reference come from on the FR circuit? It comes from the ECU, not the other way around. You need to back probe that wire with the connector plugged in to check that circuit.
The ECU supplies the voltage. When the alternator works harder, its regulator brings the FR voltage down by grounding it. The ECU monitors the voltage and uses it as a reference for how much it needs to increase engine RPM.


There is NO load detection on any wire connected to the voltage regulator. It does NOT sense a LOAD on the S circuit. Its IMPOSSIBLE for any meaningful load be carried on that circuit.
We don't know exactly what it detects. Perhaps it only senses up to 10 amps.


There is no DATA. CANBUS did not exist back then. The ONLY thing it reads.... is voltage because its SAFE.
The voltage in the FR circuit is used by the ECU as analogous data which the computer then uses in the form of digital data when running it through its program. An example of this program is:

// ECU
motoridle() {
if ($coolanttemp >= 150) {
$motoridle = 800;
}
while ($motorrpm >= 500) {
if ($fr <= 300) {$motoridle = $motoridle + 100};
}


IG ignition circuit only tells the voltage regulator when the vehicle is on literally by the presence of battery voltage
Ignition circuit is a power source only. The regulator is not energised without ignition power.


You will notice a trend here... Every wire going to the voltage regular is voltage input. The voltage regulator does not output on any circuit.
B outputs current to the battery, L signal outwards to the human, and FR signals outwards to the ECU.


SO, the correct conclusion you should come to is, if charging is controlled by the voltage regulator, it can only make decisions based on the voltage it is detecting. Therefore, if you have found a voltage drop on any circuit..... you should fix that first.
The voltage drop is on the ignition circuit. Its hard to say if it is affecting with without interfacing with its micro control unit. I will find out tomorrow when I run it straight to the battery.


What these amatuers should have done was created an ECU error notification for the owner by adding something into the ECU's program, such as this:

// Regulator
if ($s = 0) {$frground = 5; pause 2; $frground = 10; pause 2};

// ECU
while ($motorrpm >= 500) {
$frerror = {$frerrorvalue = $frgroundvalue; pause 2; $frerrorvalue = $frerrorvalue + $frgroundvalue};
if ($frerrorvalue >= 10 && $frerrorvalue <= 20) {$ecuerrorcode21 = true} else {$frerrorvalue = 0};
}

The regulator cannot digitally talk to the ECU, but it can signal it by alternating grounding from 4.95 volts to 4.90 volts every 2 seconds. The ECU can monitor the voltage and check the voltage every 3 seconds. If the sum of both checks equals approximately 15 volts, then that can be interpreted as the regulator advising it cannot sense any voltage and notify the technician. Instead, here I am messing about with an undocumented, technically unintuitive piece of shit.
 

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Discussion Starter · #202 · (Edited)
I've been thinking..... Its not the S circuit. When the alternator is charging and you pull the S fuse, the alternator ups charging from 14 volts to 15 volts. When you pull the fuse after the battery charge light comes on, nothing happens, meaning the regulator isn't functioning, meaning its not getting ignition power.

0.4 voltage drop at the alternator plug on IG, 0.034 at the other end of the socket where the power comes from

So I have to pull the loom, unwrap it and replace the IG wire. I have no idea how I am going to get the pin out of the socket at the top of the engine bay. Maybe I can just cut out the bad part of the wire and join a new part in.

It will be interesting to see how the hell the ignition wire went bad.
 

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Discussion Starter · #205 · (Edited)
So I jumped the S circuit, it made no difference. I jumped the IG circuit, it made no difference. I jumped the FR circuit, it made no difference.

The oil light flickered again tonight with the ignition on, motor off.

Also, another problem has developed since rigorously feeling and jolting the engine wire harness and grounding points two night ago. The temperature gauge now goes right up as soon as I start the car, from cold! And it moves around, mostly hovering around overheating.. and here is where it gets really interesting.. as soon as the battery charge light turns on (alternator stops charging), the temperature gauge comes down to normal and stops playing up.


Its like things are shorting out or have wires have rubbed through each other in the harness and fussing with each other.

With the battery charge light on, I get 12 volts when doing a voltage drop test by setting the multimeter to DCV 20 and putting a multimeter probe on the ignition circuit on the alternator plug and a probe on the battery positive post. That doesn't sound right.
 

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Discussion Starter · #207 · (Edited)
According to page 16-114 of the shop manual, the oil pressure switch should be open when the engine is running and grounded when the engine doesn't run. The fact it flickers with the engine off suggests there is an open in its wire running through the engine wire harness.

I must have shredded wires in my engine wire harness. The oil gauge and temperature sender is contacting something that is grounded, making them go haywire. And the alternator? I don't know.

This is probably related to my headlights going up and down non-stop when turned on, too.

Tomorrow I will pull apart the engine wire harness.
 

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You have gone down the rabbit hole on this pretty simple issue. Its a broken/rubbing wire grounding out and causing the issues.
Bypass the charge harness and start from there. I almost guarantee thats your issue, or possibly worn through harness somewhere on the backside of that harness.
 

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Discussion Starter · #210 ·
If it was a pretty simple issue, we all wouldn't be here in 2022 talking about why my alternator would suddenly turn off.

When you say bypass the charge harness, are you talking about the B circuit on the alternator or are you talking about the engine wire harness?

I'm not bypassing anything anymore. I already know the problem is in the engine wire harness. Tomorrow I am pulling it apart.
 

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By pass that charge harness, you overcomplicated this issue. You have been pointed down more simple methods of figuring it out, and yet you chose to go down a crazy rabbit hole.
Our cars are not OBD2 so they do not get controlled by the ecu, they are simple OBD0/1 cars that are a simple electronic setup.

I told you to bypass that charge harness from the beginning weeks later, you have gone way off track.
You could have solved this weeks ago, but for whatever reason a squirl seems to distract you and then you go down further into the rabbit hole.

You have been helped, at this point if you want to make it harder on yourself, then this all on you.
Good luck.
 

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Discussion Starter · #212 · (Edited)
I still don't know exactly what you mean by charge harness so I can't do what I don't understand. There is no such thing as a charge harness.

No, I have tried almost every method presented to me, none of them worked.

Yes, our cars are controlled by the ECU, that's why it says PGM-FI on the throttle body.

I have been helped, but I'm the one that found the problem. There's no rabbit hole about it. It was a difficult problem to diagnose as all circuits show correct voltage and all the components work.
 

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Discussion Starter · #213 ·
You are NOT GOING TO BELIEVE how badly I have screwed up. So the whole time I have been testing the IG, S and L circuit has been wrong.

I have test the circuits either at the alternator plug or between the engine wire harness and left engine compartment wire harness, here!:
Motor vehicle Automotive fuel system Electrical wiring Gas Auto part


Well fuckin, apart from FR, they don't even run up there! They run around to the fuckin under-hood relay box! Those wires in the pic above all probably go to the ECU!

I have the engine wire harness out of the car and have just been doing resistance checks on the alternator related circuits and noticed I wasn't getting anything up there apart from FR, then my heart sank as I realised how badly I have screwed up.

The same coloured wires go to the ECU but they are thinner wires. If you have a look at this photo in the background, there are the same coloured wires, but thicker- like the ones that run from the alternator plug (BLU/WHT, GRN/WHT and YEL/BLK) because they those wires coming from the alternator plug!
Finger Electrical wiring Gas Gadget Cable



I set my multimeter to 200 ohms. Touching both probes gave me a reading of 00.3. Then I tested the alternator circuits and got the following readings:

WHT/RED (FR): 00.3
WHT/GRN (S): 00.3
WHT/BLU (L): 00.3
BLK/YEL (IG): 00.3
WHT (B): 00.2


I don't know what the significance of B being 00.1 less than the rest, perhaps its because the cable is a lot thicker?

I'm not sure what that white goo is inside the big plug but I think its dialectic grease. I'm about the completely clean that plug and its socket with contact cleaner and bring it up nice. Hopefully doing that as well as getting rid of oil still amongst the wires will fix the problem. I'm also going to unwrap that end all the way down to the wires because there is still oil trapped in it.

I don't think I covered those wires when I hosed down the engine.

Things are looking up with this piece of shit car! :)
 

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Hopefully doing that as well as getting rid of oil still amongst the wires will fix the problem............................

YOUR KIDDING RIGHT? what do you think oily wires are doing? you know that engines get wet and oily and are designed to run this way? (unless you flood the ignition circuit) you are always going down one rabbit hole after another. As others have tried to help you, the charging circuit is SIMPLE if, as you say the "alternator is new", and you haven't "blown it up", if the 3 terminals B, S, IG, are connected to (+V) and the case is grounded (-V), IT MUST CHARGE PERIOD, this is how they are tested on an alternator test bench.......... it really doesn't get easier that that!!!! so disconnect the harness, now using 2 new wires, connect battery 12+ to S and IG pins of the alternator, (assuming you leave the main battery wire connected to the B terminal) and check the voltage and current..............EASY, you have been told this before but you always find pointless areas to check! if after you have done this "BASIC" test the output is correct, then you can then identify which wire is causing the issue, by connecting the "test wire" you connected to the S wire connection in the loom/plug and re-test, (leave the IG connected to 12+) if it is still working the S circuit is OK, then do the same with the IG wire and re-test, if the fault reappears you have found the faulty wire in the LOOM/PLUG.

You should also connect a test light from +12v to the L terminal to monitor this output. should light up when engine stopped and go out when started and charging. this terminal goes from basically ~0v when off to >12v+ when charging (causing the light to go out) .
 

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Discussion Starter · #215 · (Edited)
Ok, so I put the engine wire harness back in and the problem persists. But the alternator is now charging/not charging sporadically.

Now that I know IG, S and L run from the alternator to the fusebox, I'll do some tests at the fusebox. The problem must be between the fusebox and ignition barrel, everywhere else has been either replaced or checked.

So disappointed.

Going back to my voltage drop test data, IG and L stick out, and IG powers L. I know the drop on IG is a problem but I don't know what to make of it:

(Multimeter set to DCV 2000m)

BLK/YEL (IG) at alternator plug (unplugged) to battery positive post: 400
WHT/BLU (L) at alternator plug (unplugged) to battery positive post: 363
WHT/GRN (S) at alternator plug (unplugged) to battery positive post: 037
WHT/RED (FR) at alternator plug (unplugged) to battery positive post: 001
Alternator B post to battery positive post: 038
Alternator body to battery negative post: 007
Thermostat housing ground to battery negative post: 008


I got a new packet of fuses. I'm going to replace the fuses on IG and S.
 

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Replacing all
the fuses (again) didn't do anything.
STOP Pissing about and do theiis simple test,
charging circuit so SIMPLE if, as you say the "alternator is new", and you haven't "blown it up", if the 3 terminals B, S, IG, are connected to (battery 12+V) and the case is grounded (-V), IT MUST CHARGE PERIOD, this is how they are tested on an alternator test bench.......... it really doesnt get EASIER that that!!!! so disconnect the harness, now using 2 new wires, (NOT THE ONES IN THE LOOM) direct battery 12+ to S and IG pins of the alternator, (assuming you leave the main battery wire connected to the B terminal) and check the voltage and current..............EASY, you have been told this before but you always find pointless areas to check! if after you have done this "BASIC" test the output is correct, then you can then identify which wire is causing the issue, by connecting the "test wire" you connected to the S wire connection in the loom/plug and re-test, (leave the IG connected to 12+) if it is still working the S circuit is OK, then do the same with the IG wire and re-test, if the fault reappears you have found the faulty wire in the LOOM/PLUG.

You should also connect a test light from +12v to the L terminal to monitor this output. should light up when engine stopped and go out when started and charging. this terminal goes from basically ~0v when off to >12v+ when charging (causing the light to go out) .
 

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Discussion Starter · #218 ·
I'll bet this problem is being caused by a rusted grounding at G471. I have bad leaking rear lights. The trunk has rusted, and the back seat gets soaking wet from the condensation. G471 is bang smack behind the back seat. My retractable headlight problem only happens when using the stick switch which grounds to G471. I can't explain how the alternator is affected but my temperature gauge pegging with the engine running and then dropping down to normal when the alternator stops charging is some how linked and the temperature gauge also grounds to G471.

I look forward to sharing my rabbit hole findings.
 

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Discussion Starter · #220 · (Edited)
I used a file and contact cleaner to clean G471. It didn't help. I then used a file and contact cleaner to clean G1, G2, G101, G201, G202, and G203. Also, I stripped the screw on G291 so couldn't file it but I used contact cleaner on it.

I started the car for ten seconds but turned it off as it was 3 AM. The battery charge light was off and it had been all day, having started it about 10 times during the day. The temperature gauge and retractable headlights are still playing up. The engine is also ruff idling but that could be because the engine is very low on coolant (it does that auto choke thing once it warms up from low coolant).

Things are looking better but its too early to say if the charging system is fixed. Given the gauge is still playing up, its probably not fixed and the charging system will stop working after a minute of running the car. I will check tomorrow (today).

If its not fixed then I will continue cleaning every ground in the car; remaining: G3 (appears missing), G301, G302, G401, G402, G501, G701, G821.



Oh yeah Faulcun, if you have a look at the wiring diagram of the charging system, you can see the ECU is 'PGM-FI ECU'. PGM-FI means programmed fuel injection. The ECU in this car is for the fuel injection system only- no alternator controlling function. This car is so old.
 
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