Easy Way to Check Voltage Reg. on 98 Civic?
 

Is there an easy way to check the voltage
regulator on a 98 Civic?

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Al" <ecarecar@yahoo.com> wrote in message
news:10tj2gbmmm5ib57@corp.supernews.com...
> Is there an easy way to check the voltage
> regulator on a 98 Civic?

You need to check the voltage across the battery with the engine running. A
digital voltmeter, even the cheapest one, is the best way.

The voltage should be between 13 and 15 volts DC, higher voltages in the
range with lower temperatures. Also measure the AC voltage across the
battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
be sure the alternator has bad diodes. If the regulator is bad but the
alternator is working, the voltage will be much too high or much too low. 17
volts DC is a typical regulator failure voltage, and that will quickly
destroy the battery.

Are you having problems with the battery not staying charged?

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Al" <ecarecar@yahoo.com> wrote in message
news:10tj2gbmmm5ib57@corp.supernews.com...
> Is there an easy way to check the voltage
> regulator on a 98 Civic?

You need to check the voltage across the battery with the engine running. A
digital voltmeter, even the cheapest one, is the best way.

The voltage should be between 13 and 15 volts DC, higher voltages in the
range with lower temperatures. Also measure the AC voltage across the
battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
be sure the alternator has bad diodes. If the regulator is bad but the
alternator is working, the voltage will be much too high or much too low. 17
volts DC is a typical regulator failure voltage, and that will quickly
destroy the battery.

Are you having problems with the battery not staying charged?

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
>
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tj2gbmmm5ib57@corp.supernews.com...
> > Is there an easy way to check the voltage
> > regulator on a 98 Civic?
>
> You need to check the voltage across the battery with the engine running. A
> digital voltmeter, even the cheapest one, is the best way.
>
> The voltage should be between 13 and 15 volts DC, higher voltages in the
> range with lower temperatures. Also measure the AC voltage across the
> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
> be sure the alternator has bad diodes. If the regulator is bad but the
> alternator is working, the voltage will be much too high or much too low. 17
> volts DC is a typical regulator failure voltage, and that will quickly
> destroy the battery.

In addition to Michael's suggestions:

The nominal voltage is 14.5 volts under normal circumstances. Factory
manual allows up to 15.1 volts. In my experience voltage regulators are
very accurate, +/- 0.1 volts is what I have seen.

Some Honda's use a system where the set-point for the voltage regulator
is reduced at idle. On mine (94 Civic), stepping on the brakes will
defeat this reduction.

To better asses the health of your voltage regulator you should measure
the voltage pr. Michael's instructions while you gradually increasing
the engine RPM. The voltage should stabilize as you get a little above
idle, and it should never exceed 15.1 volts. I usually go up to about
3000 RPM, and if the voltage is still steady, I am happy.

According to factory manual, if you reach 18 volts, abort the test, as
excess voltage can damage electronic components in the car.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
>
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tj2gbmmm5ib57@corp.supernews.com...
> > Is there an easy way to check the voltage
> > regulator on a 98 Civic?
>
> You need to check the voltage across the battery with the engine running. A
> digital voltmeter, even the cheapest one, is the best way.
>
> The voltage should be between 13 and 15 volts DC, higher voltages in the
> range with lower temperatures. Also measure the AC voltage across the
> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
> be sure the alternator has bad diodes. If the regulator is bad but the
> alternator is working, the voltage will be much too high or much too low. 17
> volts DC is a typical regulator failure voltage, and that will quickly
> destroy the battery.

In addition to Michael's suggestions:

The nominal voltage is 14.5 volts under normal circumstances. Factory
manual allows up to 15.1 volts. In my experience voltage regulators are
very accurate, +/- 0.1 volts is what I have seen.

Some Honda's use a system where the set-point for the voltage regulator
is reduced at idle. On mine (94 Civic), stepping on the brakes will
defeat this reduction.

To better asses the health of your voltage regulator you should measure
the voltage pr. Michael's instructions while you gradually increasing
the engine RPM. The voltage should stabilize as you get a little above
idle, and it should never exceed 15.1 volts. I usually go up to about
3000 RPM, and if the voltage is still steady, I am happy.

According to factory manual, if you reach 18 volts, abort the test, as
excess voltage can damage electronic components in the car.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Randolph" <trash@junkmail.com> wrote in message
news:41DB9E2E.5D5DEF42@junkmail.com...
>
> Michael Pardee wrote:
>>
>> The voltage should be between 13 and 15 volts DC, higher voltages in the
>> range with lower temperatures. Also measure the AC voltage across the
>> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>> can
>> be sure the alternator has bad diodes. If the regulator is bad but the
>> alternator is working, the voltage will be much too high or much too low.
>> 17
>> volts DC is a typical regulator failure voltage, and that will quickly
>> destroy the battery.
>
> In addition to Michael's suggestions:
>
> The nominal voltage is 14.5 volts under normal circumstances. Factory
> manual allows up to 15.1 volts. In my experience voltage regulators are
> very accurate, +/- 0.1 volts is what I have seen.
>
The voltage is compensated to match the battery's response to temperature.
In Phoenix warmed up cars in the summer can read as low as 13.2 V. Here in
Flagstaff the locals tell me the winter voltage can get close to 16 volts,
but I've never seen it above 15 in anything. My '85 Volvo has a temperature
sensor mat the battery sits on that connects to the (built-in regulator in
the) alternator.

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Randolph" <trash@junkmail.com> wrote in message
news:41DB9E2E.5D5DEF42@junkmail.com...
>
> Michael Pardee wrote:
>>
>> The voltage should be between 13 and 15 volts DC, higher voltages in the
>> range with lower temperatures. Also measure the AC voltage across the
>> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>> can
>> be sure the alternator has bad diodes. If the regulator is bad but the
>> alternator is working, the voltage will be much too high or much too low.
>> 17
>> volts DC is a typical regulator failure voltage, and that will quickly
>> destroy the battery.
>
> In addition to Michael's suggestions:
>
> The nominal voltage is 14.5 volts under normal circumstances. Factory
> manual allows up to 15.1 volts. In my experience voltage regulators are
> very accurate, +/- 0.1 volts is what I have seen.
>
The voltage is compensated to match the battery's response to temperature.
In Phoenix warmed up cars in the summer can read as low as 13.2 V. Here in
Flagstaff the locals tell me the winter voltage can get close to 16 volts,
but I've never seen it above 15 in anything. My '85 Volvo has a temperature
sensor mat the battery sits on that connects to the (built-in regulator in
the) alternator.

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tj2gbmmm5ib57@corp.supernews.com...
>
>>Is there an easy way to check the voltage
>>regulator on a 98 Civic?
>
>
> You need to check the voltage across the battery with the engine running. A
> digital voltmeter, even the cheapest one, is the best way.
>
> The voltage should be between 13 and 15 volts DC, higher voltages in the
> range with lower temperatures. Also measure the AC voltage across the
> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
> be sure the alternator has bad diodes. If the regulator is bad but the
> alternator is working, the voltage will be much too high or much too low. 17
> volts DC is a typical regulator failure voltage, and that will quickly
> destroy the battery.
>
> Are you having problems with the battery not staying charged?
>
> Mike
>
>

No. It's just a hunch and probably wrong.

I bought the car new. About a year later the air bag
SRS? light went on. I took it to the dealer. They fiddled
with it, couldn't find anything wrong, reset the light and
sent me away. About a week later, the light came back on.
I went to the dealer and went through the same process and the
light came back on a few days later. Since
I didn't plan on having an accident, I ignored the light.

About 6 months after that, the check engine light came on. Eventually
ignored that, too.

The one thing I have noticed is that if you release the accelerator
from whatever constant speed, the lights - and particularly the
check engine indicator - dim while the engine is slowing and, I'm
fairly certain, the SRS light and check engine light were triggered
while the engine was either at idle or slowing to idle.

I just wondered if the system voltage dropped to a level that
might cause these faults to trigger? Just a wild guess.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tj2gbmmm5ib57@corp.supernews.com...
>
>>Is there an easy way to check the voltage
>>regulator on a 98 Civic?
>
>
> You need to check the voltage across the battery with the engine running. A
> digital voltmeter, even the cheapest one, is the best way.
>
> The voltage should be between 13 and 15 volts DC, higher voltages in the
> range with lower temperatures. Also measure the AC voltage across the
> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you can
> be sure the alternator has bad diodes. If the regulator is bad but the
> alternator is working, the voltage will be much too high or much too low. 17
> volts DC is a typical regulator failure voltage, and that will quickly
> destroy the battery.
>
> Are you having problems with the battery not staying charged?
>
> Mike
>
>

No. It's just a hunch and probably wrong.

I bought the car new. About a year later the air bag
SRS? light went on. I took it to the dealer. They fiddled
with it, couldn't find anything wrong, reset the light and
sent me away. About a week later, the light came back on.
I went to the dealer and went through the same process and the
light came back on a few days later. Since
I didn't plan on having an accident, I ignored the light.

About 6 months after that, the check engine light came on. Eventually
ignored that, too.

The one thing I have noticed is that if you release the accelerator
from whatever constant speed, the lights - and particularly the
check engine indicator - dim while the engine is slowing and, I'm
fairly certain, the SRS light and check engine light were triggered
while the engine was either at idle or slowing to idle.

I just wondered if the system voltage dropped to a level that
might cause these faults to trigger? Just a wild guess.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Randolph <trash@junkmail.com> wrote in message
news:41DB9E2E.5D5DEF42@junkmail.com...
>
> Michael Pardee wrote:
> >
> > "Al" <ecarecar@yahoo.com> wrote in message
> > news:10tj2gbmmm5ib57@corp.supernews.com...
> > > Is there an easy way to check the voltage
> > > regulator on a 98 Civic?
> >
> > You need to check the voltage across the battery with the engine
running. A
> > digital voltmeter, even the cheapest one, is the best way.
> >
> > The voltage should be between 13 and 15 volts DC, higher voltages in the
> > range with lower temperatures. Also measure the AC voltage across the
> > battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
can
> > be sure the alternator has bad diodes. If the regulator is bad but the
> > alternator is working, the voltage will be much too high or much too
low. 17
> > volts DC is a typical regulator failure voltage, and that will quickly
> > destroy the battery.
>
> In addition to Michael's suggestions:
>
> The nominal voltage is 14.5 volts under normal circumstances. Factory
> manual allows up to 15.1 volts. In my experience voltage regulators are
> very accurate, +/- 0.1 volts is what I have seen.
>
> Some Honda's use a system where the set-point for the voltage regulator
> is reduced at idle. On mine (94 Civic), stepping on the brakes will
> defeat this reduction.
>
> To better asses the health of your voltage regulator you should measure
> the voltage pr. Michael's instructions while you gradually increasing
> the engine RPM. The voltage should stabilize as you get a little above
> idle, and it should never exceed 15.1 volts. I usually go up to about
> 3000 RPM, and if the voltage is still steady, I am happy.
>
> According to factory manual, if you reach 18 volts, abort the test, as
> excess voltage can damage electronic components in the car.

Radio Shack used to carry a lighter plug-in battery checker that gave some
of that info. The they had last I checked has five levels and two "ranges"
for running and engine-off. You have to rig it for a cig lighter or else
manually connect it somewhere. The only thing it doesn't explicitly do is
check the ripple (AC), but you can usually see that as rapid flashing of two
voltage levels.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Randolph <trash@junkmail.com> wrote in message
news:41DB9E2E.5D5DEF42@junkmail.com...
>
> Michael Pardee wrote:
> >
> > "Al" <ecarecar@yahoo.com> wrote in message
> > news:10tj2gbmmm5ib57@corp.supernews.com...
> > > Is there an easy way to check the voltage
> > > regulator on a 98 Civic?
> >
> > You need to check the voltage across the battery with the engine
running. A
> > digital voltmeter, even the cheapest one, is the best way.
> >
> > The voltage should be between 13 and 15 volts DC, higher voltages in the
> > range with lower temperatures. Also measure the AC voltage across the
> > battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
can
> > be sure the alternator has bad diodes. If the regulator is bad but the
> > alternator is working, the voltage will be much too high or much too
low. 17
> > volts DC is a typical regulator failure voltage, and that will quickly
> > destroy the battery.
>
> In addition to Michael's suggestions:
>
> The nominal voltage is 14.5 volts under normal circumstances. Factory
> manual allows up to 15.1 volts. In my experience voltage regulators are
> very accurate, +/- 0.1 volts is what I have seen.
>
> Some Honda's use a system where the set-point for the voltage regulator
> is reduced at idle. On mine (94 Civic), stepping on the brakes will
> defeat this reduction.
>
> To better asses the health of your voltage regulator you should measure
> the voltage pr. Michael's instructions while you gradually increasing
> the engine RPM. The voltage should stabilize as you get a little above
> idle, and it should never exceed 15.1 volts. I usually go up to about
> 3000 RPM, and if the voltage is still steady, I am happy.
>
> According to factory manual, if you reach 18 volts, abort the test, as
> excess voltage can damage electronic components in the car.

Radio Shack used to carry a lighter plug-in battery checker that gave some
of that info. The they had last I checked has five levels and two "ranges"
for running and engine-off. You have to rig it for a cig lighter or else
manually connect it somewhere. The only thing it doesn't explicitly do is
check the ripple (AC), but you can usually see that as rapid flashing of two
voltage levels.

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Al" <ecarecar@yahoo.com> wrote in message
news:10tp4cveu58psf8@corp.supernews.com...
> Michael Pardee wrote:
>> "Al" <ecarecar@yahoo.com> wrote in message
>> news:10tj2gbmmm5ib57@corp.supernews.com...
>>
>>>Is there an easy way to check the voltage
>>>regulator on a 98 Civic?
>>
>>
>> You need to check the voltage across the battery with the engine running.
>> A digital voltmeter, even the cheapest one, is the best way.
>>
>> The voltage should be between 13 and 15 volts DC, higher voltages in the
>> range with lower temperatures. Also measure the AC voltage across the
>> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>> can be sure the alternator has bad diodes. If the regulator is bad but
>> the alternator is working, the voltage will be much too high or much too
>> low. 17 volts DC is a typical regulator failure voltage, and that will
>> quickly destroy the battery.
>>
>> Are you having problems with the battery not staying charged?
>>
>> Mike
>
> No. It's just a hunch and probably wrong.
>
> I bought the car new. About a year later the air bag
> SRS? light went on. I took it to the dealer. They fiddled
> with it, couldn't find anything wrong, reset the light and
> sent me away. About a week later, the light came back on.
> I went to the dealer and went through the same process and the
> light came back on a few days later. Since
> I didn't plan on having an accident, I ignored the light.
>
> About 6 months after that, the check engine light came on. Eventually
> ignored that, too.
>
> The one thing I have noticed is that if you release the accelerator
> from whatever constant speed, the lights - and particularly the
> check engine indicator - dim while the engine is slowing and, I'm
> fairly certain, the SRS light and check engine light were triggered
> while the engine was either at idle or slowing to idle.
>
> I just wondered if the system voltage dropped to a level that
> might cause these faults to trigger? Just a wild guess.

Sounds like a possible alternator (not regulator) problem, all right. The
most common defect of this sort is bad diodes, and an AC voltage reading
across the battery at idle will tell the story on that. If the alternator is
bad, forget about the rebuilts from auto stores - they have earned a very
bad reputation for frequent failure. The stores may offer a lifetime
warranty, but they won't pay the labor to have it replaced.

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

"Al" <ecarecar@yahoo.com> wrote in message
news:10tp4cveu58psf8@corp.supernews.com...
> Michael Pardee wrote:
>> "Al" <ecarecar@yahoo.com> wrote in message
>> news:10tj2gbmmm5ib57@corp.supernews.com...
>>
>>>Is there an easy way to check the voltage
>>>regulator on a 98 Civic?
>>
>>
>> You need to check the voltage across the battery with the engine running.
>> A digital voltmeter, even the cheapest one, is the best way.
>>
>> The voltage should be between 13 and 15 volts DC, higher voltages in the
>> range with lower temperatures. Also measure the AC voltage across the
>> battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>> can be sure the alternator has bad diodes. If the regulator is bad but
>> the alternator is working, the voltage will be much too high or much too
>> low. 17 volts DC is a typical regulator failure voltage, and that will
>> quickly destroy the battery.
>>
>> Are you having problems with the battery not staying charged?
>>
>> Mike
>
> No. It's just a hunch and probably wrong.
>
> I bought the car new. About a year later the air bag
> SRS? light went on. I took it to the dealer. They fiddled
> with it, couldn't find anything wrong, reset the light and
> sent me away. About a week later, the light came back on.
> I went to the dealer and went through the same process and the
> light came back on a few days later. Since
> I didn't plan on having an accident, I ignored the light.
>
> About 6 months after that, the check engine light came on. Eventually
> ignored that, too.
>
> The one thing I have noticed is that if you release the accelerator
> from whatever constant speed, the lights - and particularly the
> check engine indicator - dim while the engine is slowing and, I'm
> fairly certain, the SRS light and check engine light were triggered
> while the engine was either at idle or slowing to idle.
>
> I just wondered if the system voltage dropped to a level that
> might cause these faults to trigger? Just a wild guess.

Sounds like a possible alternator (not regulator) problem, all right. The
most common defect of this sort is bad diodes, and an AC voltage reading
across the battery at idle will tell the story on that. If the alternator is
bad, forget about the rebuilts from auto stores - they have earned a very
bad reputation for frequent failure. The stores may offer a lifetime
warranty, but they won't pay the labor to have it replaced.

Mike

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tp4cveu58psf8@corp.supernews.com...
>
>>Michael Pardee wrote:
>>
>>>"Al" <ecarecar@yahoo.com> wrote in message
>>>news:10tj2gbmmm5ib57@corp.supernews.com...
>>>
>>>
>>>>Is there an easy way to check the voltage
>>>>regulator on a 98 Civic?
>>>
>>>
>>>You need to check the voltage across the battery with the engine running.
>>>A digital voltmeter, even the cheapest one, is the best way.
>>>
>>>The voltage should be between 13 and 15 volts DC, higher voltages in the
>>>range with lower temperatures. Also measure the AC voltage across the
>>>battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>>>can be sure the alternator has bad diodes. If the regulator is bad but
>>>the alternator is working, the voltage will be much too high or much too
>>>low. 17 volts DC is a typical regulator failure voltage, and that will
>>>quickly destroy the battery.
>>>
>>>Are you having problems with the battery not staying charged?
>>>
>>>Mike
>>
>>No. It's just a hunch and probably wrong.
>>
>>I bought the car new. About a year later the air bag
>>SRS? light went on. I took it to the dealer. They fiddled
>>with it, couldn't find anything wrong, reset the light and
>>sent me away. About a week later, the light came back on.
>>I went to the dealer and went through the same process and the
>>light came back on a few days later. Since
>>I didn't plan on having an accident, I ignored the light.
>>
>>About 6 months after that, the check engine light came on. Eventually
>>ignored that, too.
>>
>>The one thing I have noticed is that if you release the accelerator
>>from whatever constant speed, the lights - and particularly the
>>check engine indicator - dim while the engine is slowing and, I'm
>>fairly certain, the SRS light and check engine light were triggered
>>while the engine was either at idle or slowing to idle.
>>
>>I just wondered if the system voltage dropped to a level that
>>might cause these faults to trigger? Just a wild guess.
>
>
> Sounds like a possible alternator (not regulator) problem, all right. The
> most common defect of this sort is bad diodes, and an AC voltage reading
> across the battery at idle will tell the story on that. If the alternator is
> bad, forget about the rebuilts from auto stores - they have earned a very
> bad reputation for frequent failure. The stores may offer a lifetime
> warranty, but they won't pay the labor to have it replaced.
>
> Mike
>
>

AC reading across the battery?

Shorted diode?

If that is the right area, couldn't it be an open diode?

Re: Easy Way to Check Voltage Reg. on 98 Civic?
 

Michael Pardee wrote:
> "Al" <ecarecar@yahoo.com> wrote in message
> news:10tp4cveu58psf8@corp.supernews.com...
>
>>Michael Pardee wrote:
>>
>>>"Al" <ecarecar@yahoo.com> wrote in message
>>>news:10tj2gbmmm5ib57@corp.supernews.com...
>>>
>>>
>>>>Is there an easy way to check the voltage
>>>>regulator on a 98 Civic?
>>>
>>>
>>>You need to check the voltage across the battery with the engine running.
>>>A digital voltmeter, even the cheapest one, is the best way.
>>>
>>>The voltage should be between 13 and 15 volts DC, higher voltages in the
>>>range with lower temperatures. Also measure the AC voltage across the
>>>battery - it should be less than 0.1 VAC. If it is over 1/2 volt AC, you
>>>can be sure the alternator has bad diodes. If the regulator is bad but
>>>the alternator is working, the voltage will be much too high or much too
>>>low. 17 volts DC is a typical regulator failure voltage, and that will
>>>quickly destroy the battery.
>>>
>>>Are you having problems with the battery not staying charged?
>>>
>>>Mike
>>
>>No. It's just a hunch and probably wrong.
>>
>>I bought the car new. About a year later the air bag
>>SRS? light went on. I took it to the dealer. They fiddled
>>with it, couldn't find anything wrong, reset the light and
>>sent me away. About a week later, the light came back on.
>>I went to the dealer and went through the same process and the
>>light came back on a few days later. Since
>>I didn't plan on having an accident, I ignored the light.
>>
>>About 6 months after that, the check engine light came on. Eventually
>>ignored that, too.
>>
>>The one thing I have noticed is that if you release the accelerator
>>from whatever constant speed, the lights - and particularly the
>>check engine indicator - dim while the engine is slowing and, I'm
>>fairly certain, the SRS light and check engine light were triggered
>>while the engine was either at idle or slowing to idle.
>>
>>I just wondered if the system voltage dropped to a level that
>>might cause these faults to trigger? Just a wild guess.
>
>
> Sounds like a possible alternator (not regulator) problem, all right. The
> most common defect of this sort is bad diodes, and an AC voltage reading
> across the battery at idle will tell the story on that. If the alternator is
> bad, forget about the rebuilts from auto stores - they have earned a very
> bad reputation for frequent failure. The stores may offer a lifetime
> warranty, but they won't pay the labor to have it replaced.
>
> Mike
>
>

AC reading across the battery?

Shorted diode?

If that is the right area, couldn't it be an open diode?