Won't Charge then Won't Start - 2 for the price of 1

[gratefuljoe]

Alrighty All, I'll try to be brief :roll:

2 Electrical Problems, 1 after the other.  

91 Golf 1.6 NA (300k), new alternator, new belt (tightened recently), old wiring.

-I started the car and the battery light stayed on for longer than usual.  
-Then it flickered out, however, it came back on as soon as the rpm climbed over 800rpm.  
-The light stays on while driving, accept for very low rpm and idle.
-Obviously the battery wouldn't charge, so I charged it between drives.  -This behavior resulted in a dead battery (battery was fairly old)

I couldn't quite figure out what was going wrong.  The alternator is new.  I took out the voltage regulator (brushes) and they look just fine.  One would assume that the belt was slipping, however, I assure that it wasn't, I checked it a bunch of times.

*I did potentially do damage to the voltage regulator: when tightening the belt, my wrench bridged some of the points on the back of the regulator to the positive terminal and there was a brief spark.  May this have done in the alternator?

THEN:

-I swapped in a fully charged battery to start her up and get her to the shop and she wouldn't crank over at all.
-All accessories work and the glow plugs fired.
-When I twist the key to start, there's no sound at all (no solenoid sound, and certainly no cranking sound).
-This happened about 3 times in the past, however, removing and replacing the positive cable from the battery solved the problem and she started.  This time, no such luck.

Any ideas?  I suppose I could attempt to bridge the starter to see if there's power going to it.  However, are there any connections to check?  I had just recently sanded down the grounds.  

In any case, any help would be massively appreciated.

All the best,

gratefuljoe
Edmonton, AB
1991 Golf 1.6 NA 300k

[Doug]

Take a set of jumper cables connecting one cable end to the positive of the battery. Connect the other end directly to the starter motor terminal to see if the motor will crank. I suspect that you have a bad ground or positive cable connection. Can you put a voltmeter across the battery while you do this? I seriously doubt that a momentary ground at the back of the alternator whilst tightening would do harm unless your model has a fusible link in the wiring that has let go that is not obvious.

[jtanguay]

i've sparked stuff under the hood many times.  i think only microchips would be affected by a spike, depending on where you close the circuit.  (electricity takes the path of least resistance right... so the junction would have the peltier effect and the battery would get hot because of all the electrons flowing so quickly.)

i love driving a car with no computers to mess up!  my clock did reset when i accidently sparked though....  :lol:

[somolovitch3]

That spark was (possablely - probably) your diodes going to ........(well, lets just hope it is a better place).

Get that checked out.

Belt should have a 5 mm deflection in the crank to Alt section when tight.

Agree with the bad Ground, Positive cable conection idea.

What kind of shape is/are the cable(s) in themself? Free of crud and that loverly green stuff creeping out of the insulation?

On the jumper cable trick, also run one from the Negitive post on battery to the frame of the starter.  Yes I know there is not a lot of room in there.
Run the Negitive one under the car and bring the positive one down from the top. Warning, there will be a big spark when you make contact with the stater post, don't jump and hurt yourself.

Cheers! :twisted:

[burn_your_money]

You'll need a helper for this

Have them turn the key to start and hold it there. Don't do this for extended periods of time, you'll start a fire or explode your battery. 30 seconds with a 2 minute wait should be fine

With your multimeter set to volts place one lead on a batter post and the other end on the clamp around it. If you have a reading over 0.2V you have a bad connection.

Next leave the lead on the clamp there and put the other lead on the end of that wire. Again, over 0.2V and you have a bad wire. Replace it or recrimp it.

You have to be cranking (or attempting to crank) while you are getting the readings.

Basically clean up or replace any area where you get a reading over 0.2V. Check all the charing and cranking wires/connections using this method and you'll find your problem

[bigblockchev]

Assuming that you have a multimeter do a couple of things. First disconnect the battery and snug up the starter cable connections and all the other battery cable connections, just a bit not to break things off. You can clean off corroded terminals by pouring HOT water on them use a kettle if necessary. Then reconnect the battery cables to the posts and hook your meter leads on the DC volts setting across the battery. The battery voltage with no load should be 12.5 to 13V if the battery is good and fully charged. If it will crank over check the voltage while cranking, it should not drop much below 10V if it does your battery is not great, not well charged or your starter is getting tired. If it starts turn on your lights, fans, rear defogger, in short every thing. If you then rev the motor you should see at least 13.5-14V on your meter. This tells you that the alternator is good. If you don't see the voltage climb at all either the alternator is bad or your belt is not tight enough.  This should point you in the direction of where the problem lies. An interesting statistic is that 60% of all calls to BCAA are because of loose battery terminals. Cheers Dan

[gratefuljoe]

Thanks guys, I'll have some time to attempt your suggestions tomorrow.  I'll post back.