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Discussion Starter #1
Ok ok, I know I should have cleaned the connections before I post this message, but this is really bothering me.

I just installed a new CD player and it turns itself off whenever I pull to a stop. To be exact, whenever I disengage the clutch and press the brake. Also whenever I engage reverse.

I've checked my generator (alternator) and all the wirings, and the voltage of my battery (engine stop or running), all seem to be fine to me - with a decent charging amp and a slightly low voltage. (12.4 stop, 13.5 idle)

I am just wondering is that a specific voltage for the charging light to be turn on and off (really dim, only can been seen at night)? It doesn't make sense to me that the light is off when idle but dimly on when running.
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The weird thing --
Idle, complete stop, with brake on: battery light completely off, radio turns off

Car begins to run-
battery light starts to brighten, radio turns on

car running -
battery light dimly on, radio still on

clutch disengaged, car running, engine idle -
battery light off, radio still on

cluth disengaged, car STOPPED, engine idle -
battery light off, radio still on

if I step on the brake now, the radio will turn off

:D
 

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Discussion Starter #2
Spec

Anyone has the spec for an Alfa electrical system check-up?

non running voltage & amp
idle voltage & amp
running voltage & amp

output test from alternator? :confused:

Can't find anything on the web nor the manuals I have.

Thank you for the help. Thank you.
 

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sounds like you have a bad ground to the radio are you grounded to the chasis?? Also try getting the 12 volt supply for the radio from a different source.What I did was I used a relay to supply my radio with power , I found a 12 volt supply from the ignition when it was in the onposition and used this to activate the relay.This way i was sure not to get any low voltage issues.Or you can connect the radio directly to the battery and press the brake to see what happens.
 

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It definitely sounds like your alternator.

I was driving my GTV6 in rush hour traffic on the 110 at the 101/5 interchange. Twice I stepped on the brakes and the radio turned off. Then the car started sputtering and coughing. Somehow I crossed four lanes of traffic to get to the shoulder before it completely died. Turned out that my alternator was producing just enough power to keep the car running. The radio was just too much.

A beautiful CHP officer pushed my car off the freeway to safety. She and I....well that's another story.
 

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Probably prudent to check the alternator output first. The following info is from the CARDISC CD Alfa service manual:

Disconnect the wire from the B+ terminal on the alternator.

Connect a voltmeter between the B+ terminal and ground. Start engine. Should read 12-13 volts with engine running.

Connect ammeter between B+ terminal and battery + terminal. Reading should be 20-30 amps.

Agree with others that all connections need to be checked clean and tight. Check especially the grounds. Might also check for any wire chafing around movable items, like brake and clutch pedals.
 

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I had the same problem in my Milano. I was driving with the lights, wipers and radio going. After about 45 minutes of driving, my radio would shut off when I came to a stop light. I had to rev the engine to keep the radio on. The alternator was the weak link. Actually, it was the voltage regulator.
 

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OK Jeff,

We're all adults here. Let's hear the story about the Hot Cop...
 

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Discussion Starter #8
I've just took the time to clean all the connections (under the 96F SoCal Sun)
Here are my readings -

Alternator B+ > Ground = 13-16V (it moves violently) I cannot find a 30A ammeter to measure B+ > Battery + :(

Battery voltage -
Engine not running - 12.56
Cranking - 10.33
Idle - 13.2x
Increase engine to 1500rpm - 13.5
3000rpm with load (everything on) - 13.02-13.06
However, whenever Irelease the gas, and the engine idle again it slowly drops to12.41 :confused:

Another thing - it seems the battery is not holding voltage pretty well. I've charged the battery to 12.70 volt one night, and then it becomes 12.6 again the other day, and it keeps dropping.

Time for a new Optima Red Top?
Would the 35 fit? :D

Or do I need a new voltage regulator too? Or even a new alternator (that's going to hurt my wallet :( )

Thank you everyone.


Roadtrip said:
Connect a voltmeter between the B+ terminal and ground. Start engine. Should read 12-13 volts with engine running.
 

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Hi, I believe that you should trouble shoot your problem based on the reaction of the "battery" light and put the radio reaction aside for now. The radio is an unknown and using it to diagnose means you have two unknowns working.
So how does the light work with the radio off. Remember that the light is a charging indicator. If you have more current being produced than is being used, the light cannot light. If you are using more than the alternator is sending to the battery the light comes on. If the light comes on with the radio out of the picture, your alternator is not creating enough current or the regulator is not allowing enough current to go to the battery. Once the engine is running, the alternator should supply the current needed the battery should not need to supply any and the light should stay OFF.
If the light does not behave properly with the radio out of the picture, forget the radio and have your charging circuit checked.
The regulator is most often the problem but not always.
If the light works OK with the radio off, the alternator is not creating enough current to supply everything. Now you need an ammeter. You need to determine if the power produced is too little (<30 amps) or the power needed is too much (>30amps).
I have used a lot of words to say the same thing as others (alternator/regulator output is too low) but I think it is important to understand what is happening. The radio could be simply overloading the alternator. 50 watts for the speakers is 4+ amps, a couple more for the CD motor and you are using 6 amps.
MrC
 

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Sounds like the voltage test is good. As long as the voltage is above 12, it'll charge the battery.

Really need to do a Amp test. Check out Walmart or an Discount Auto Store for one. Or better yet, mooch one off a friend. An ampmeter is important because it will tell you if the alternator is putting out sufficient CURRENT (vice voltage). Also, an ampmeter can tell you if there's a short somewhere (even with the key off) that can slowly drain the battery. If you do have current being drawn off the battery with the key off (assuming there's no clocks, etc running on a hot bus), you can probably isolate the problem circuit by removing fuses one at a time until the ampmeter show zero.

Have you checked for bad cells in the battery with a specific gravity battery tester? If you don't have one, they're a couple of bucks at Walmart.

BTW, what kind of radio do you have . . . . one of those 500W blasters?

Are you sure you've check the clutch and brake pedal area for interfering wires, pinched wires and inadvertent shorts?

Of all problems, electrical ones are probably the most frustrating. Take you time and think logically.
 

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Discussion Starter #11
I really need to get an ampmeter. :)

Went to all auto part stores in my area, without luck. All they got are some cheapo gauges. Went to Fry's today, all they got is the CLAMP (induction?) one ($149.99), with rating at 1000A and 400A (the same one my dad uses to test those 330V industrial generators and circuit breakers >400A)
Are they accurate enough to test a 20A 30A generator? :confused:

Thank you. :D

I never though it would be that hard to buy an ampmeter.

One thing I am certain now is the radio turns off whenever the voltage drops below 12.50. That is when the car is idling and with either a headlight/turn signal/back up light is on.

Gotta drop by Harbor Freight, HomeDepot & WalMart tomorrow.
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I've just replaced the Pioneer cassette player with a Clarion CD Player (50Wx4). It somehow fits the styling of the GTV dash nicely, all black with a tiny chrome knob. No fancy displays and buttons.
 

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Discussion Starter #12
Ammeter

Maybe I've been looking for the wrong gauges.
I was looking for a electronic instrument style ammeter, with accuracy down to two decimal points. :p

Would this work?
 

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First off, I am no expert in any of this. With that said, would a power amplifier for the stereo help things out? I had a 25Wx4 cd player in my old Honda with eight speakers. They'd cut out if I turned up the volume past half way.

When ever I had electrical problems, I'd go to Sears for a free check. They'd give me the answer, I'd thank them and then go buy the part (battery or alternator) myself. Could this help?
 

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Sears or any other good battery store is probably a good bet here.
The dash type ammeter will certainly work but be very careful how you handle it. You are hopefully going to run 30 amps through it and 30 amps will burn a hole in a lot of things.
The inductive ammeter (clamp around the wire type) will also work fine as long as the scale will show 30 amps. The value that you want should be in the middle of the scale.

With all of the electronics/electrics in todays cars, 30 amps does not offer a lot of reserve. I will try to get some research done on alternators that are readily available, mechanically compatible and have 50 to 60 amp capability.
MrC
 

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You're looking for the wrong stuff. What you need is an "Engine Analyzer." These were common before the advent of electronic ignitions. The one I have is about 20 years old and still works perfectly. It's a Sears Penske Model # 244.21033, about the size of a cinder block. I don't even know if they sell them new anymore given that the new cars are all have EFI and electronic ignitions.

Mine measures:

1. Point resistance
2. RPM
3. Volts 0-16 & 3-32
4. Amps -5 to 90
5. Ohms 0-40k
6. Spark output

The generally come with all the cables and shunts necessary to test a generator or alternator for max output.

I looked over on Ebay (under "engine analyzer") and there are loads of them available in good condition for $5 -$20. If you get one off ebay, be sure the instruction booklet, cables, and shunt come with it. The instruction book is really important because it will show you exactly how to make the connections to test what you want to and not damage something, yourself included. Even an anemic Bosch 30A alternator can really stand your hair on end.
 

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Discussion Starter #16 (Edited)
Yes they still have it in Sears!! :D

It's now made by Craftsman though. It looks like a very useful piece of tool, gotta have it. :D

I saw similar products in Fry's, about triple the pirce of the Sears one, but they're all electronic and doesn't measure the amp at all.

Thank you RT, thank you everyone. I really appreciate it.

Roadtrip said:
You're looking for the wrong stuff. What you need is an "Engine Analyzer."
 

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Another couple of things to go with it are a compression tester and a vacuum gauge/fuel pressure tester. I think I saw a used Sears analyzer (like the one in your picture) on ebay that included those things as well, all at a really good price.
 

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Discussion Starter #18
The new Sears Craftsman one doesn't come with any of those. :(


I think this is the one that you've, is that correct?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3025329073&category=14932

Let me try to bid on that one. :D It has EVERYTHING!


Roadtrip said:
Another couple of things to go with it are a compression tester and a vacuum gauge/fuel pressure tester. I think I saw a used Sears analyzer (like the one in your picture) on ebay that included those things as well, all at a really good price.
 

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Discussion Starter #19

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If all you are doing is checking the amperage, you can use a multimeter they are fairly in expensive.You can check voltage and amperage with it , that is all you need right now from what i am reading.A digital one would probally work best than a analog one.But the Sears unit would work and offers more of a variety.
 
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