My voltage drops from 14 to 12(-), at idle/when coming to a stop...
If the climate blower is turned on high or the a/c is engaged, voltage jumps instantly back to 14.
When it drops, its noticeable -lights dim, fan slows, and my stereo turns off (resets).

I have no trouble with draining, or a constant low voltage while the car is running under load...
Battery always has a 12v when sitting.

I dont think Im running anything excessive - Just an Alpine, which req's direct draw from the battery, but no amp or subs.

Battery is relocated to the trunk, but its been there for years and this is a new problem.
I used 0 guage wire on that install...
Battery is less than 1 yr old. Dry-cell Odyssey.

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I vaguely remember reading something about checking the alt with a multimeter, at the battery?? I dont want to pull the damn thing to have it tested, if I can do it myself.

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edit**
Found this thread: https://honda-tech.com/zerothread?id=919581
A few people suggested the iacv or the distributor - both of mine are new (less than 6 months each)
Found several other threads with the same issues. Problem is, no one mentioned solving the problem and most of the users that experienced it are no longer active...


Modified by pdiggitydogg at 7:15 PM 10/5/2008

 

1st i would check your wiring since you relocated. like if you have bare/frayed wire touching metal, bad grounds etc...

2nd i would check the battery. use a battery tester to check CCA. this will tell you if you are under charged or have a bad cell

3rd i would test the alternator.

go for the easiest/cheapest fix first cause it may be something dumb like a frayed wire

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by honda.lioness &raquo;</TD></TR><TR><TD CLASS="quote">Try the quick and dirty alternator checks listed at http://honda.lioness.googlepag...rtips </TD></TR></TABLE>

I'll have to read that checklist. Thats worth something, thanks.
And its the original alt from 97, so its older.

 

Up for some more insightful replies.
Strange problem, if you ask me - never encountered it before.
No battery light either, btw.

 

One useful suggestion? This forum section is getting ridiculous, having only a handful of helpful people, when it comes to real tech. Drives me nuts that out of the thousands, there are less than 15 who can help with real questions.

I bought a new brush assembly online - will install and update the thread for future help.

 

Get a clamp ammeter and full field the alternator. If it doesnt put out at least its max rated amperage, your alt is ****.

 

Or if you have/know of someone or a shop with a VAT-40 tester, zap it with that.

 

run the test with the multimeter at the battery, with the car off should read about 12v with car running should be closer to 14v, if thats good sounds like possible the VRM(voltage regulator module) its part of the alt, can be replaced, consult the helms for TS the VRM

gl

this is also assuming all grounds and connections are good

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by egsleepercivic &raquo;</TD></TR><TR><TD CLASS="quote">run the test with the multimeter at the battery, with the car off should read about 12v with car running should be closer to 14v, if thats good sounds like possible the VRM(voltage regulator module) its part of the alt, can be replaced, consult the helms for TS the VRM

gl

this is also assuming all grounds and connections are good </TD></TR></TABLE>

Dude...please read before posting.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pdiggitydogg &raquo;</TD></TR><TR><TD CLASS="quote">My voltage drops from 14 to 12(-), at idle/when coming to a stop...
If the climate blower is turned on high or the a/c is engaged, voltage jumps instantly back to 14.

I have no trouble with draining, or a constant low voltage while the car is running under load...
Battery always has a 12v when sitting.[/b]
</TD></TR></TABLE>
Ok, so I missed the overcharge bit, but I did say "voltage drop".

And yeah, I know tons of people with VAT-40 units........
I've flipped through Helms, too. I disregarded it and am asking how to setup the multimeter at the battery to test for amperage.
Standard garage tools here...guys.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by King V &raquo;</TD></TR><TR><TD CLASS="quote">Get a clamp ammeter .</TD></TR></TABLE>

Standard garage tool

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pdiggitydogg &raquo;</TD></TR><TR><TD CLASS="quote">
Helms.</TD></TR></TABLE>

Standard garage tool

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by King V &raquo;</TD></TR><TR><TD CLASS="quote"> clamp ammeter .</TD></TR></TABLE>

If you use a multimeter to check amperage from an alternator, you'll fry it. Flukes can only take 10-20 amps when run to test for amperage. Hence my suggestion. And if you don't know how to set up a multimeter to read amps, maybe you should put the alternator on a bench and have it tested that way.

 

same problem in my jeep wen im comin to a stop my jeep actualy shakes on a voltage drop to just under 12 but wen driving constant its steady 14 i think my alternator is old though. its weird though b/c itll vibrate and shake on the voltage drops to 12 but nothing turns off. only voltage drops wen cold and at stops and accelerating at a couple mph.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by King V &raquo;</TD></TR><TR><TD CLASS="quote">
If you use a multimeter to check amperage from an alternator, you'll fry it. Flukes can only take 10-20 amps when run to test for amperage. Hence my suggestion. And if you don't know how to set up a multimeter to read amps, maybe you should put the alternator on a bench and have it tested that way.</TD></TR></TABLE>

I know how to set up amps on a multimeter, and some are rated for more amps than others. Ive seen them with 4gauge wires, which are capable.

And no, a clamp ammeter is not a std garage tool. Multimeter is. No one is questioning Helms.

 

Weird, I have the same problem. I have a 96 DX. It's completely stock except that I, too, have reccently installed an Alpine V-Drive deck that requires a direct connection to the battery. Before the deck install, I didn't have any alternator-related problems. I even jumped two cars a couple months ago... wasn't a problem. Now, when I'm in park or slowing down to a stop, the alternator light comes on, and the car dies. I've had alternators die on me before, and it was never like this... a slow fade out. But just wanted to bump this thread to see if the OP solved his problem.

 

I read some where on here that it is common for the voltage to drop to around 12 with no load. Someone said it had to do with the load detector in the ecu. there resolution was to keep the fan switch set at 2 to make the ecu detect a draw and switch the alt to charge at the higher rate.

From my own experiance with my car and alt problems the after market radio has always been a good indicator of a failling alt. When I started to get alt wine across the sound system it wasent to long before the alt would crap out.

Just before this last change out I installed a volt meter to keep an eye on things. This has given me insite into the way the charge system works and I have noticed that on little to noo load the voltage will drop to right around 12v and with the fan on 2 it always stays at 13.5 to 14 volts

It sounds like your alt is starting to go out. the symptoms you are having are the same sort of things that always happen when mine start going out

 

Oh last thing if you do have an amp meter that is capable of high amp and is not a clamp type. disconect the plus cable from the battery clamp the neg cable to the wire and the plus to the battery. set the meter to amp scale and you should be good to go

 

I appreciate the insight, finally something helpful.
I do have a volt gauge connected, in-dash, and ive been monitoring this for awhile.

I started to swap the brushes yesterday, but the lower bracket bolt was completely seized... Drilled it out as much as I cared to, then just modded a newer b series alt I had sitting around instead (the top needs shaving for the upper d bracket)

I am fairly confident the new brushes would solve the issue, they were very loose when I inspected them through the pin-hole (for new install purposes).
Im going to head to the parts store later, to pick up a weird belt size for this...its between 33.5-35". Will update after....even though a completely different/newer alternator should take care of it, regardless

 

Bump - How did you resolve this issue, Mr. Pdiggitydogg? :-)

I experience the same cut-outs once in a while in me EG2 (Euro) - Especially if the fan is not set to 2 or more.

Have a nice Easter :-)

 

Get your alternator tested.

 

You'll do much better by making your own thread rather than bumping an old one.