EDIT:
Problem solved! It was the alternator all along!
I guess the used alt I got to replace the last one, ended up having the exact
same ******* symptoms.. and when I took to have it tested, it tested as A-OK.
yet when I swapped in YET another alternator, it fixed the problem.
thanks.
-----------------------------------------------------------------------------------------

OK i've been trying to figure out this prob for a while now.
My lights(headlights/dash/dome/etc) pulsate brighter to darker erratically.
The voltage I see at my batt. terminals jumps around from 14v to mid 15's erratically.

turning my fans to full blast with the headlights on seems to help tone this down,
but I need to fix this.

This all started when I put in my supercharger,
I have narrowed it down that the alternator is installed correctly,
the supercharger belt is on correctly and tight.
I can't find any loose grounds, or busted fuses.

BUT when I was first putting in the SC I had a problem blowing 80A battery fuses due to the alt touching the supercharger and shorting.
By the time I figured what the problem was I had blown a buncha fuses,
and ended up just using a wire to connect the fuse point and see if it sparked.
OK this was probably stupid, but I got tired of spending 5bux each time the fuse popped. So i'm thinking something got damaged due to that short.

Can you guys give me an idea what I should check?
I'm really noob at electrical/wiring systems, but I do have a multimeter.

I really want my car to work! the JRSC runs great, everything is good to go, it's just this last problem I need to fix!
I'd have a shop look at it but it's thankgiving weekend.. 4 more days of no hatch is fucked.

thanks in advance.
edit: heres the charging system diagram 4 my car.



Modified by Tad at 10:27 PM 11/24/2004


Modified by Tad at 6:16 PM 12/12/2004

 

it sounds like the alternator screwing up on u or the wrong one or connected wrong

but sounds so much like that

 

Voltage regulator. If it's integral with the alternator, then that has to be replaced. Check the alternator to battery connection before you yank it.

 

oh, also I went to kragen and hadem hook up their diagnostic doohickie to my car.
It said that both my battery and alternator were good.
(anyone notice that any non-honda guys are always baffled by how small our radiators are??? haha).
i'm thinking something is causing the voltage reg(yes its inside the alt) to overproduce.

I just don't know how to find what's causing it.

 

Intermittent electrical problems are tough to pinpoint. I'd check the alt to batt cable as well as the engine ground strap.

Borderline brushes or diodes could also cause this, but the test supposedly said it was good.

 

YEAH they are!
and yeh the cable is good.
at least up until it hits the fuse box.
hmm.. time to do some lookin there..

 

Alt cable goes through a fuse? What YMM is it? I'll look up the wiring diagram after I recover from this weekend's tryptophane binge and go look it up on Mitchell On-Demand on Monday.

 

before it hits the battery yes.
it goes from the alt to the fuse box, does some craziness in there, and hits the battery fuse(80A)
then goes from the fusebox to the pos. battery terminal.

i've got a helms, i'm looking thru right now, but it's pdf format and my comp is giving me ****

 

I'd look real hard there. Check for corrosion on the fuse contacts. In fact, try using a beefy jumper wire to bypass all that stuff and see if your light flickering goes away. The refresh rate on most DVOMs won't catch it fast enough to give you any useful info anyway. It'll just jump all over the place.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid2nr &raquo;</TD></TR><TR><TD CLASS="quote">The refresh rate on most DVOMs won't catch it fast enough to give you any useful info anyway. It'll just jump all over the place.</TD></TR></TABLE>

hmmm, lost me on that part

 

The DVOM will read voltage drops fairly steadily, even with fluctuating voltages, on sections that have good connections. When it's testing on a section with intermittent contacts, that's when it goes nuts. You're reading a flash sample that's close to a second old on some DVOMs. Try the jumper and see if the lights go steady.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tad &raquo;</TD></TR><TR><TD CLASS="quote">BUT when I was first putting in the SC I had a problem blowing 80A battery fuses due to the alt touching the supercharger and shorting.
By the time I figured what the problem was I had blown a buncha fuses,
and ended up just using a wire to connect the fuse point and see if it sparked.
OK this was probably stupid, but I got tired of spending 5bux each time the fuse popped. So i'm thinking something got damaged due to that short.</TD></TR></TABLE>

You got anymore more info you're neglecting to tell us? I've been following your problem and haven't read about blown fuses, espceially the monster 80A.

You also neglected to say that the voltage jumps up to 20v sometimes, or does it not do this anymore.

The alternator you have in there right now sounds like it has a busted regulator/recitifier. Did this particular alternator suffer from shorting out and blowing that 80A fuse?

And all to often, AutoZone or Pepboys are incorrect in their assesment of alternator/battery operation - don't rely to heavily on their diagnosis.

Try this, measure the AC voltage across your battery terminals - what do you got? Yep, the alternator actually generates an AC signal that is recitified to DC and if one of the diodes in the bridge goes bad, you'd see an increase in AC ripple voltage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">You got anymore more info you're neglecting to tell us? I've been following your problem and haven't read about blown fuses, espceially the monster 80A.

You also neglected to say that the voltage jumps up to 20v sometimes, or does it not do this anymore.

The alternator you have in there right now sounds like it has a busted regulator/recitifier. Did this particular alternator suffer from shorting out and blowing that 80A fuse?

And all to often, AutoZone or Pepboys are incorrect in their assesment of alternator/battery operation - don't rely to heavily on their diagnosis.

Try this, measure the AC voltage across your battery terminals - what do you got? Yep, the alternator actually generates an AC signal that is recitified to DC and if one of the diodes in the bridge goes bad, you'd see an increase in AC ripple voltage.</TD></TR></TABLE>

thanks,
yeah I did actually mention the blown fuses in some of my previous posts,
but i mentioned alot of stuff so I can see it being easily missed.
this was not the alternator causing the original short that blew those fuses.
(that was a denso type that I couldnt use cuz it hit the SC, i'm now on my 2nd mitsu type, first one did the same high fluctuating voltage thing, but eventually stopped giving out any volts).

I didn't mention the 20V surge in this post because I can't reproduce that problem,
I took a wire brush and terminal cleaner to my battery terminals, and battery fuse terminals. After that things actually seem alittle better.
CURRENTLY my charge light doesn't ever come on, whereas it used to flicker on/off randomly(usually when the engine was under load).

but the wacky voltage still persists.
just I believe it's contained below 16V(at least i hope it is.. maybe i should hookup some wires to the batt so I can monitor it while i'm driving.. hmm).

But yeah, i'll check the AC volts at the battery and report back!
if my multimeter has AC that is.

 

I had the pulsating headlights, and interior lights. I was also throwing a CEL for the ELD code 20.

Turn out to be an exposed wire rubbing against a motor mount had shorted.

 

heh, if only i DID have a CEL, then i'd have some clue where to look.

but anyways,
I drove the car around today, and took a look at the voltage occasionally. for most of the day everything was actually normal! volts chilled at around 14v, I couldn't get it to waver much at all, revving the engine or driving it around.
lights didnt flicker either.

but sigh.. the problem is still there, my battery light came really dim for a minute, then got bright er to full brightness.. then went off.
lights started flickering.. then it went back to normal.

GAH!!
and I checked the AC volts, it stayed at around 0.001 but occasionally if I watched it long enuf it'd pop up higher, then drop back down real quick.

Ima try and take the whole fuse box out and up to my room where I can examine it closer..

 

I would do a test for the regulator then the ELD, but to be honest since that battery light is turning on I have to say the regulator is full fielding and is not turning off, The alternator controls the output voltage depending on what it sees, there is a variable resistor that changes with voltage and temp that regulates how much the field should turn on and off which increases / decreases your voltage output, I bet in the cold or cold temps the problem is not there but as it gets hotter it shows up?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BatuKing &raquo;</TD></TR><TR><TD CLASS="quote">I would do a test for the regulator then the ELD, but to be honest since that battery light is turning on I have to say the regulator is full fielding and is not turning off, The alternator controls the output voltage depending on what it sees, there is a variable resistor that changes with voltage and temp that regulates how much the field should turn on and off which increases / decreases your voltage output, I bet in the cold or cold temps the problem is not there but as it gets hotter it shows up?</TD></TR></TABLE>

yessir! I kept being fooled thinking the problem was fixed,
I'd start the car, and it'd read low 14v steady.. then drive off and after a while things start getting wacky!

But my last alternator did the same thing. If I can find a third i'll try it.
But one thing that has to be done to all the alternators is I have to rotate the power terminal 90deg. to clear my supercharger. Is that ok?

 

how did you clock it? just move the shield on the nut or did you dissassemble it and move the top part of the alternator?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tad &raquo;</TD></TR><TR><TD CLASS="quote">yessir! I kept being fooled thinking the problem was fixed,
I'd start the car, and it'd read low 14v steady.. then drive off and after a while things start getting wacky!</TD></TR></TABLE>

You need to solve the voltage spike probs, and at this point I would say it would be safe to say it's very likely not your alt by itself. Voltage fluctuations such as those caused by poor connections or bad voltage regulators (alt diodes too) will drive the ecu voltage regulator nuts (the internal one that converts batt voltage to 5V). That's guaranteed to set codes because of the unstable 5V ref to the sensors.

I would also take a really close look at the FR (field regulator?) connection (blue wire). I didn't catch this earlier because your wiring diagram hadn't loaded earlier - thanks to my dialup. It seems to suggest that perhaps your alt field is regulated by the ecu. Before you blame the ecu, make sure that connection is solid and tight. It may have been damaged by prior alt replacements. It's also not uncoomon that a prior tech may have even jammed his DVOM probe in a connector - either at the alt or the ecu multi-pin connector - causing the female pins to spread slightly. (Don't laugh, cars have been lemon lawed that were later found to have had this exact thing happen. OEMs have special pin connector packs specifically made for techs to use for DVOM checks. The one GM sells is about $175. It's just a little baggie with a bunch of specialized adapter wires. If the FSE determines that a tech didn't use that, the dealer eats it in a big way. FSEs pound on the dealers super hard on this one, so it often resulting in the tech getting fired.) If this connection or circuit is compromised in any way, this very well could be the culprit. It fits all the scenarios described.

The next thing I would check is to find any other load-related ecu inputs, such as power steering pressure, AC controller, etc. On some systems, the ecu automatically jacks up the field current, which would increase alt output. If the input is intermittent, the ecu FR current would fluctuate as well in an attempt to keep up. I would try to temporarily isolate these and see if the voltage is steady inder varying vehicle operating conditions.

If you monitor alt output current, system voltage, and field current, you would also be able to determine if it was the ecu at fault (ALWAYS the last resort).


Modified by hybrid2nr at 10:24 AM 11/27/2004

 

well it's not the ecu,
just threw in my CX ecu, and it did the same thing.

still havent been able to get under the car to examine the wires though.

 

yea.. check the ground wire for the regulator, a bad ground for that will cause whats happening to your car.

 

OK I was able to do some more diagnosing on the car today.

I went through the helms troubleshooting flowchart.
the wires at the connector that plugs into the ELD checked out good(battery voltage showing up where it should be).

BUT, the helms asks you to check voltage between the pins d10(+) and a26(-)
with the headlights on full, and just parking lights on.
it's supposed to be like this
full 1.5 - 2.5V
park 2.5 - 3.5V

what i got(now it my whole problem is voltage bouncing around, so it was not a steady reading, but this is the range i got)

full 1.3 - 1.5V
park 2.2 - 2.4V

SO is that it?! Is the ELD the culprit!?
according to helms, if you dont get the specified values you should replace the ELD.
and thats exactly what i'm going to do. i'll lyk how it turns out.

Btw: the way the honda ECU plugs flip open letting you access the pins without actually unplug it is SOOOOOOO handy!! made things alot easier

 

nope.. swapped out the ELD and no change.

took the alt off and went to kragen to have it tested, just to make sure.
it tested out good.

checked the C, and F wires that run from the alternator to the ecu. Continuity checked out ok on both, and visually they look ok.

all grounds look fine..

i've tried a different ecu, no change.
checked all my fuses..

is there even anything else to check!?!?

the only extra electral component i have installed in the car is the JR map sensor kit(i dont even have a freakin radio).. but I can't find anything wrong there either, it taps into the 02 wire, and the IAT wires, and one power wire.. I just used butt connectors for everything.

 

up for one stumped mufuka

 

My vote goes with the voltage regulator in the alternator.

My MR2 just did the same thing. I installed a plug-in voltmeter and watched it constantly for a few weeks. The voltage would sit low, and the lights would kinda dim a little sometimes, and yet sometimes the voltage would sit at around 15.1 volts. It finally died and left me stranded.

I also had it tested twice at Autozone and they said the alternator and battery were fine. That didn't stop it from dying a week and a half later!