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Discussion Starter · #61 · (Edited)
LOL IT SOLVED THE FUCKIN PROBLEM!!! !

  • Three months
  • Two replacement alternators
  • Replacement crankshaft pulley
  • Replacement drive belt

And all the problem was, was a fucking oil leak getting into the engine wire harness! Water must have pushed oil into the engine wire harness when I hosed down the engine, the WD-40 cleared it!

What has this taught me? Check in-your-face problems which arn't covered by the manual!

Thanks Stub & Wing8806 & DON NADIE & geonit & Faulcun & davidpham1029 & Kabuki for helping out!
 

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Discussion Starter · #62 · (Edited)
Ah FFS! The problem has returned again but not like before. The battery charge light comes on now only once the engine has warmed up.

I am almost sure it is the wire carrying the FR signal that is the culprit as cleaning it was the only thing that got the battery charge light to turn off.

I ended up cleaning the engine wire harness again where the oil had soaked it with throttle body cleaner as it's all I had. It was strong and did an alright job but perhaps there's still oil trapped inside the engine wire harness. I might do another round of cleaning it out of desperation but if there is oil trapped in the harness then I think it won't be coming out. I think I'm in big trouble.

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I found a page for the FR signal in the fuel-injection section of the shop manual.


The page confirms that the wire carrying the FR signal is 5 volts, and the page has a troubleshooting flowchart that I'm going to carry out tomorrow.

I read somewhere (and the manual page confirms it) that the 5 volts is a reference voltage that drops down (anywhere down to 1.2 volts) depending on the electrical load, and that the alternator uses the voltage reference to determine how hard it should charge. I would like to think the 0.49 volt loss in the wire between the node and the alternator connector has something to do with it but if anything it should be making the alternator work harder. Perhaps if there is oil trapped inside the harness then it's viscosity is increasing with the engine warming up which is changing the electrical resistance in the wire. Maybe not though, the troubleshooting flowchart says to let the engine warm up first, so maybe what ever the reason for that is where the problem is at.

I can't let go of this car now, I am so close and I don't like being defeated.

I am interested to hear thoughts.
 

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I dont believe the harness is your issue. Like I said, run a bypass wire on your FR circuit, and that will confirm your problem. But most 5v reference circuits range from .2-4.8v
 

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Discussion Starter · #64 · (Edited)
I know you have said a couple of times that you don't think it's the engine wire harness but the issue only started going away once I cleaned the oil off it, that's why I think it is the engine wire harness.

I'm not sure what you mean by "bypass wire". Do you mean pull the terminal out of the back of the alternator connector and insert a new terminal with a wire running to the node? When I say node I mean this:

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Do you know how to get the terminals out of the connector? I have tried with my pick set but I can't figure it out.

Also, I don't suppose you know if the engine wire harness is the same across the third generation? If my wiring can't be fixed then I may get a replacement engine wire harness.

Do you have an opinion about the charge light now only coming on after the engine has warmed up?
 

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My opinion on the light is the same. You are drawing down the battery to the point where it gets too low and because the alternator is not charging, the light comes on. The light literally comes on only when the voltage of the battery is below a certain threshold. It actually has nothing to do with the alternator itself. You can easily verify this by watching your battery voltage while the engine is running. Think of the light as the answer to a simple question: Is battery voltage above 11.2v: yes/no? Yes - light off, no - light on.

You dont need to pull pins out. You need to use probes like i linked in post #59. They have a needle that cleanly punctures the side of the wire. Do this on your FR wire. Simply put one close to the alternator, and one on the other side of the harness connector where you circled, then connect a clean wire to the probes. If you think your harness is the issue, then your problem should be fixed with this parallel wire in place. At this point, you can spend money on a new harness, or whatever else.

I suspect that you'll see the same result

Again, be careful about having a string of bad alternators.
 

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Discussion Starter · #66 · (Edited)
So I ran further tests today using a multimeter. Here are the results:

Battery positive post and battery negative post with car off: 12.5 volts

Battery positive post and battery negative post with engine running and battery charge light off: 14.5 volts

Battery positive post and battery negative post with engine running and battery charge light on: 12.51 volts

Battery positive post and alternator body with car off: 12.46 volts

FR terminal on alternator connector (connected) and alternator body with accessories on: 3.62 volts

FR terminal on engine wire harness node socket (connected) and alternator body with accessories on: 3.62 volts

FR terminal on node connector (disconnected) and alternator body with accessories on: 4.95 volts

FR terminal on engine wire harness node socket (connected) and alternator body with engine running and battery charge light on: 4.72 volts


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It turns out oil wasn't disrupting continuity between the alternator connector and the engine wire harness node socket. The first time I performed the test on the node I didn't know FR voltage was variable and I think I may have performed it when the engine was a bit cold and auto-choke was running the engine above 800 RPM after I had performed the rest of the tests on the circuit with the engine running at 800 RPM.

I already knew the alternator was working because the lights dim when the battery charge light is on but I ran the test anyway for the sake of science: With the engine running, 14.5 volts when the battery charge light is off; 12.51 volts when the battery charge light is on.

I see a big problem at the node where there is voltage loss between the engine wire harness node socket and node connector. With accessories on, the engine wire harness node socket is 3.62 volts and the node connector is 4.95 volts. When I removed the little rubber insert from the back of the FR terminal on the engine wire harness node socket I found water trapped inside the terminal hole which would have been from when I hosed down the engine. I wonder if that's causing the problem by disrupting the FR signal.

I'm going to let the water evaporate out of the terminal hole and then see if the problem goes away. If it doesn't then I'll run a bypass wire from the FR terminal on the node connector and see if that resolves the problem and then take it from there.

Here's a video of the battery charge light coming on once the engine warms up:



Here's a video of the battery charge light flickering on after restarting the engine while it's warm and then a strange slow auto-choke before the engine returns to normal idle:

 

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Discussion Starter · #67 · (Edited)
The FR terminal on the node connector test was flawed because I did the test with the connector disconnected.

FR terminal on engine wire harness node socket (connected) and alternator body with accessories on: 3.62 volts
FR terminal on node connector (disconnected) and alternator body with accessories on: 4.95 volts

I should have tested the FR terminal on the node connector while the connector was connected because I believe the alternator sends a signal to the ECU via FR which the ECU uses to moderate the FR voltage.

I will redo testing tomorrow but I now believe voltage is consistent throughout the FR circuit.

I think the battery charge light coming on once the engine has warmed up is a clue but I don't know what to make of it yet. It appears the ECU is being fed wrong information from somewhere which is causing it to tell the alternator to switch off.

And now I'm thinking back to how spraying the oil soaked engine wire harness made the battery charge light go from being always on to now only coming one once the engine has warmed up. I don't think that was a coincidence.
 

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Discussion Starter · #68 ·
There is one very important test that I need to do according to the troubleshooting flowchart, I meant to do it today but I forgot. I need to check the FR circuit voltage before and after turning on the headlights and rear defogger to see if the voltage drops. Voltage in the FR circuit is generated by both the ECU and the alternator which is all good but I need to check that the ECU is actually moderating it's reference voltage. If the ECU is not moderating it's reference voltage then that would explain the alternator switching off. Look at the last test:

FR terminal on engine wire harness node socket (connected) and alternator body with engine running and battery charge light on: 4.72 volts


4.72 volts is really high

I'm pretty sure it is working though otherwise the alternator would not be switched on when the car is warming up.
 

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Discussion Starter · #69 · (Edited)
So I did more tests today, here are the results:

Battery positive post and battery negative post with car off: 12.39 volts

Battery positive post and alternator body with car off: 12.39 volts

FR terminal on alternator connector (connected) and alternator body with accessories on: 3.61 volts

FR terminal on engine wire harness node socket (connected) and alternator body with accessories on: 3.61 volts

FR terminal on node connector (connected) and alternator body with accessories on: 3.61 volts

Battery positive post and battery negative post with engine running and battery charge light off: 14.52 volts

FR terminal on engine wire harness node socket (connected) and alternator body with engine running and battery charge light off: 3.69 volts

FR terminal on engine wire harness node socket (connected) and alternator body with engine running, headlights and rear defogger turned on and battery charge light off: 2.91 volts

Battery positive post and battery negative post with engine running and battery charge light on: 12.61 volts

FR terminal on engine wire harness node socket (connected) and alternator body with engine running and battery charge light on: 4.58 volts

FR terminal on engine wire harness node socket (connected) and alternator body with engine running, headlights and rear defogger turned on and battery charge light on: 4.58 volts


I can confirm that there is continuity throughout FR circuit.

I can confirm that when the alternator is on, the ECU moderates the FR reference voltage when there is a load on the electrical system.

I can confirm that once the engine has warmed up, the alternator turns off and the ECU no longer moderates the FR reference voltage when there is a load on the electrical system.


So it looks like once the engine warms up, the ECU decides to no longer moderate the FR reference voltage which could be what is causing the alternator to turn off. Look at the last two tests, the reference voltage is static at 4.58 volts. That voltage could be a high enough threshold for the alternator to turn off.

The question is why does the ECU stop moderating the FR reference voltage once the car has warmed up.

The shop manual FR signal troubleshooting flowchart goes on to instruct in letting the engine warm up and then putting a load on the electrical system. It then leads on that if there isn't a decrease in the voltage then to inspect the alternator, there is an open in the circuit or a short in the circuit.


The alternator is good, so according to the flowchart it's either an open or a short, but if it's an open or a short then why before the engine warms up does the FR voltage decrease when there is a load on the electrical system?!

What do others think?
 

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Discussion Starter · #70 · (Edited)
OMFG! I have noobed it so badly! FR and the ECU are fine! The ECU doesn't even send a signal to the alternator, it's the other way around! I got wrong information off some shit article!

I realised I had to go back to basics and had a look at alternator fundamentals and found some reliable information on an Accord forum which now makes me lean towards a theory I had earlier on today but dismissed it.

My upper radiator hose is leaking coolant right over where the loom connects that houses the wires for the IG, S and L circuits, and I think coolants' getting in and causing trouble.

This would explain why the battery charge light only comes on once the engine has warmed up - after the thermostat has opened up!


Fuckin shit car! LoL

I am going to test this theory tomorrow! :)
 

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Discussion Starter · #71 · (Edited)
Well well well

I fixed the leak. The battery charge light still came on but it took almost four times longer to come on.. way after the engine had warmed up. I thought coolant was trapped in the loom so I got a pressure bottle and blasted in between where the looms connect where the coolant was dripping onto. Then when I started the car and the battery charge light was flicking like crazy, that's never happened before. I expect water in the loom is now causing the same problem but the water will soon evaporate.

Everything now points to the coolant leak causing a short or resistance in IG, S and L circuits. Perhaps the alternators regulator is programmed to shutdown in such an event as a safety measure.

I'd like to say fixing the coolant leak will resolve the problem.

Hosing down the engine must have caused this fiasco by water getting in the loom. The first replacement alternator must have worked for the first half an hour because the engine hadn't been running for a month and the water in the loom evaporated but then half an hour later the coolant leak worked it's way into the loom.

The coolant leak must have started a day before I hosed down the engine because I changed the thermostat and mustn't have tightened properly the stupid non-OEM adjustable hose clamp on the upper radiator hose when I put everything back together. I hosed down the engine because I am in the middle of changing the power steering fluid and the bag I was using for draining the existing fluid touched the exhaust manifold and a hole burnt through causing the fluid to go everywhere.

Always consider other problems when diagnosing! The brain processes reality logically and because there is no correlation between coolant and an alternator the brain doesn't consider them at the subconcious level which in this case was the biggest fuck up!

In acting training I was taught to consider an opposite character because the brain will naturally go for the obvious character that is in the script which 9/10 of the other people in the audition room will be playing. This level neurologic applies to problem solving as well!

Thanks Faulcun for your continued support!
 

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Thanks Faulcun for your continued support!
lol thanks i guess. Im still skeptical of this harness situation though. The only thing i can figure... is a possible situation where some sheathing might be old and cracked inside the wire loom, exposing very small areas of wire to water and moisture. i suppose with the age of the vehicle.... anything is possible. But ive pressure washed many a engine bay and never came across a situation like this, even after directly spraying an alternator with water.

Never too old to learn something new though. Im intently waiting to see what the results are. :D
 

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Discussion Starter · #74 · (Edited)
Well I had a look at the loom today where the coolant has been dripping onto. There is a hole that looks like it's been eaten away. By the coolant? I don't know.. I'm not sure if coolant can even do that. I also have a massive oil leak from my CYL sensor that goes all over the place. I followed the loom to the under-hood fuse box. The loom ends at the bottom before coming up to the fuse box and there is gunky oil coming out of the loom down there! Maybe it's the oil!

If the battery charge light still hasn't gone away in a week then I am going to inject degreaser into the loom from the the hole followed by water to flush out the oil.

Yeah I have pressure washed my engine many times before as well. :\

So the battery charge light was on all day today. I kinda expected this given it took ages for the battery charge light to go off after hosing down the engine the first time.

I too am still a bit skeptical if it was the leaking coolant causing this problem but right now fixing the coolant leak has by far given me the best results, but I said that after spraying the oil off engine wire harness with WD-40 and it didn't turn out to be that so I just don't know yet.

Something interesting happened before. I turned on accessories but not the engine and after the two second cluster test, the battery charge light flickered for a few seconds. I'm not sure what too make of this but I am going to sit down after dinner and read more into alternator fundamentals and see the logic behind what makes the battery charge light come on. It's very strange that it was flickering with the engine off.
 

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Discussion Starter · #76 ·
So this was the file someone shared on the Drive Accord forum that explains the fundamentals of alternator circuitry...


The file explains IG, L, FR and C circuits. C is for computer controlled alternators. Our car predates that and has an S circuit instead.

I wanted information S circuit and found this convo...



It sounds like the alternators regulator monitors the battery voltage level via S and increases output according to the voltage level. It sounds like the more load on the electrical system, the lower the battery voltage drops, the harder the alternator works to bring the volts back up.

I have talked volts, but what about amps. My multimeter says '10 amps' for the high voltage circuit. The alternator puts out like 70 amps or something. Does this mean my multimeter would explode testing amps or is the 10 amps circuit for high voltage currents? So, can my multimeter handle more than 10 amps at 12 volts? I don't know much about electricity.

29435
 

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Discussion Starter · #79 · (Edited)
I am in the middle of drafting up an e-mail to someone who works in spare parts at my local Honda that I have good rapport with to ask him if he could get an experienced technician to have a look at my case. While I was collecting test data I noticed something interesting. Look at this:

FR terminal on alternator connector (connected) and alternator body with engine running and battery charge light on: 4.58 volts

FR terminal on alternator connector (connected) and alternator body with engine running, headlights and rear defogger turned on and battery charge light on: 4.58 volts

FR terminal on alternator connector (disconnected) and alternator body with the engine on and battery charge light on: 4.58 volts


See how in the first two tests I detected 4.58 volts on the FR terminal on alternator connector when it's connected?

Now see in the last test... 4.58 volts detected on the FR terminal on alternator connector when it's disconnected.

What this means is that the alternator regulator is shut down when the charge battery light is on.

This looks like an emergency shut down to me, likely caused by a short circuit.

I could be wrong though. The FR terminal on the alternator puts out only 3 volts with nothing connected to it. Does 4.58 volts from the ECU and 3 volts from the alternator combine to make a 7.58 volt circuit or would it still be only 4.58 volts? If it's 4.58 volts then perhaps the regulator hasn't shutdown and it's 3 volts is being cast over by the ECU's 4.58 volts.

If the ECU doesn't talk to the alternator like I hear, then why is the ECU even putting out voltage?

What do others think?
 

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Discussion Starter · #80 · (Edited)
The battery charge light came on later today which I expected. It came on after 10 minutes and 58 seconds from cold start. I am going to make a record over the next few days on how long it takes.

Tomorrow I am going to do more testing and look at other areas of the car. This problem is not consistent which means it is something physical causing it, and the problem is related to heat; something is warming up and changing state.

I might have to get funky with my tests such as removing the thermostat to induce a cold running engine to see if that keeps the alternator on. It doesn't sound logical but logic isn't doing me any favours right now.

And my local Honda dealer can fuck off with inviting me in for a diagnosis. Shit cunts.
 
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