Scirocco Dead. Alternator test?

My 88 16v Scirocco is dying after I start it drive it and park it starting
today. After getting my emissions done and going to the DMV my rocco died. A
guy gave me a jump and it fired right up.

My friend said you can test the alternator by pulling the + terminal while
running. If it dies then it's the alternator that's bad. If not, then
battery. I just wanted to make sure this would be safe on my car. I don't
have a stereo or anything. I just don't trust going to checkers and getting
the voltage checked because I've always ran pretty low volts. I guess that
might cause extra stain on the battery. I think the last time I replace
battery was in 02 or 03. Thank for any tips.. I'm tipsy.

"CMORE" > wrote in message
. ..
> My 88 16v Scirocco is dying after I start it drive it and park it starting
> today. After getting my emissions done and going to the DMV my rocco died.
> A guy gave me a jump and it fired right up.
>
> My friend said you can test the alternator by pulling the + terminal while
> running. If it dies then it's the alternator that's bad. If not, then
> battery. I just wanted to make sure this would be safe on my car. I don't
> have a stereo or anything. I just don't trust going to checkers and
> getting the voltage checked because I've always ran pretty low volts. I
> guess that might cause extra stain on the battery. I think the last time I
> replace battery was in 02 or 03. Thank for any tips.. I'm tipsy.

Not sure I quite understand or buy your friend's logic but here's what I go
by.

A battery does little/nothing to run a car. It's pretty much for starting
only and for not losing your radio presets

A car can run just fine on its alternator alone *once the engine is
running*. If your car passes that test, you're fine b/c the alternator is
putting out the juice to run the car.

If your car runs fine but simply won't start, your battery isn't accepting
the charge anymore. If it's not "maintenance free", pop the caps off and
fill with distilled water as required. If it's maintenance free, well
sometimes they really aren't "maintenance free" and you can still pop the
caps off and check/fill with water..

But on a 3 y.o. battery it might not be worth it. 3 y.o. isn't really old
but it isn't young either. Take it to a good FLAPS and have them test it.
They can tell you in about 20mins. if the rate at which it charges is good
or bad. The longest I've had a battery last is 5.5 years but after about
3-4 years any failure is pretty likely.

Your alternator would be bad only if your car would routinely wear down the
battery under normal driving. This is because instead of the alternator
putting out the juice your car would cannibalize the battery instead until
it was dead. You'd see your lights dimming and eventually the ECU wouldn't
have the juice to run the car and it eventually would die. Plus, your
alternator light would probably be on anyway under this condition.

"CMORE" > wrote:

>My 88 16v Scirocco is dying after I start it drive it and park it starting
>today. After getting my emissions done and going to the DMV my rocco died. A
>guy gave me a jump and it fired right up.
>
>My friend said you can test the alternator by pulling the + terminal while
>running. If it dies then it's the alternator that's bad. If not, then
>battery. I just wanted to make sure this would be safe on my car. I don't
>have a stereo or anything.

Bad idea. The battery acts as a filter to filter out
electrical spikes produced by the alternator. Computers (like your
fuel injection and ignition ECUs) can be killed by such spikes.
Removing the + wire while the engine is running is also very bad for
an alternator's voltage regulator.

> I just don't trust going to checkers and getting
>the voltage checked because I've always ran pretty low volts. I guess that
>might cause extra stain on the battery. I think the last time I replace
>battery was in 02 or 03. Thank for any tips.. I'm tipsy.

If the alternator was producing "low volts" then it probably
wasn't keeping the battery fully charged.


Todd
Seattle,WA
'86 GTI, Red of course. (exciting racey car) 261,000 miles
'87 Golf, Polar Silver. (boring work car) 557,000 miles <- Yeah, baby!
http://www.pureluckdesign.com <-Ferrari & VW stuff
--
NewsGuy.Com 30Gb $9.95 Carry Forward and On Demand Bandwidth

"Matt B." > wrote in message
news:U_F_f.407$zf6.378@fed1read08...

> Not sure I quite understand or buy your friend's logic but here's what I
> go by.
>
> A battery does little/nothing to run a car. It's pretty much for starting
> only and for not losing your radio presets
>
> A car can run just fine on its alternator alone *once the engine is
> running*. If your car passes that test, you're fine b/c the alternator is
> putting out the juice to run the car.
>
> If your car runs fine but simply won't start, your battery isn't accepting
> the charge anymore. If it's not "maintenance free", pop the caps off and
> fill with distilled water as required. If it's maintenance free, well
> sometimes they really aren't "maintenance free" and you can still pop the
> caps off and check/fill with water..
>
> But on a 3 y.o. battery it might not be worth it. 3 y.o. isn't really old
> but it isn't young either. Take it to a good FLAPS and have them test it.
> They can tell you in about 20mins. if the rate at which it charges is good
> or bad. The longest I've had a battery last is 5.5 years but after about
> 3-4 years any failure is pretty likely.
>
> Your alternator would be bad only if your car would routinely wear down
> the battery under normal driving. This is because instead of the
> alternator putting out the juice your car would cannibalize the battery
> instead until it was dead. You'd see your lights dimming and eventually
> the ECU wouldn't have the juice to run the car and it eventually would
> die. Plus, your alternator light would probably be on anyway under this
> condition.

Thanks a ton for the info Matt B @ Racertod! I think I'll just yank it out
when I get a chance and have them run a test at Sears. I kinda figured
pulling the + terminal would not be a very good idea to test the alternator.
But hey, my friend knows hillbilly mechanics 101 . I remember the last
time it did this was before I put the battery in that it's using now. I
think I paid like $40 or $50 from KMart for the Silverline. This car isn't a
DD so the battery hasn't had that many cranks over the years.

CMORE wrote:
> My 88 16v Scirocco is dying after I start it drive it and park it starting
> today. After getting my emissions done and going to the DMV my rocco died. A
> guy gave me a jump and it fired right up.
>
> My friend said you can test the alternator by pulling the + terminal while
> running. If it dies then it's the alternator that's bad. If not, then
> battery. I just wanted to make sure this would be safe on my car. I don't
> have a stereo or anything. I just don't trust going to checkers and getting
> the voltage checked because I've always ran pretty low volts. I guess that
> might cause extra stain on the battery. I think the last time I replace
> battery was in 02 or 03. Thank for any tips.. I'm tipsy.
>
>

Don't pull the +ive cable with the engine running, bad juju. Go ahead
and measure the voltage at the battery with the engine running, should
be about 13.7V. it really should be over 14 in an ideal world but for
some reason Bosch sets their voltage regulators lower than everyone
else. If you are not getting full voltage pull the regulator out of the
back of the alternator and check the length of the brushes, usually the
brushes wear out before anything else craps out.

good luck

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

dont run the car with the disconnected battery calls for trouble, the
'new' cars are not as heavy duty as the old fashion ones.. spikes can
hurt the ECU unit if you blow that one you will never be start your car
again until you replace the ECU for example.

Sebastian

The battery acts like a surge supressor as the power coming from the
alternator is rectified 3 phase and therefore liable to be full of
little spikes. So don't disconnect your battery while the engine is
running under any circumstances.

CMORE wrote:
> My 88 16v Scirocco is dying after I start it drive it and park it starting
> today. After getting my emissions done and going to the DMV my rocco died. A
> guy gave me a jump and it fired right up.
>

1st off: Don't Pull the Battery Cable off of the Battery when the car
is running. Don't do it.

Now then, you mention that after you get a jump the car runs OK but
won't restart without another jump, is that right?

Checking for voltage across the battery terminals with the car running
should show you more than 12 volts.

You should pull your battery and have it recharged if it is depleted
because what ever life it has left will be reduced by sitting around
run down.

Lastly, get yourself a Bentley repair manual, and a companion Hayes to
go with it. If brand new is too rich for your blood used copies can be
found online and at used bookstores in your area. It's a beautiful
thing to have the diagnostic tests right at hand.

TBerk

"TBerk" > wrote in message
ups.com...
> Checking for voltage across the battery terminals with the car running
> should show you more than 12 volts.

I get over 12.5 with the engine off, goes up to a but under 14 when running.

When my alternator died I was still getting 12.3 or .4 with the engine running.

- Bill

Those results sound like the Battery is the one producing the 12.x
readings, but when the car is running and the Alt is in good shape the
"goes up to a (bit) under 14 when running" part is what is expected.

C'More, let us know how it turns out.


TBerk