Alternator or something else?

[Fel]

Hi everyone,
I faced a problem. I have a 340 GL 1.7 carb. 1986
Engine running almost well, but last night, when I was driving almost all the night something with electricity went wrong.
All the lights dimmed during ~1h.
Strange thing is that there was no battery warning light.
And of course, after such a ride, battery is almost fully discharged now.
With discharged battery engine still worked fine (I didn't feel any lack of spark).
Maybe you can tell me wether to change an alternator or search for the problem with the wiring?

P.S. Sorry, have no time to check with a voltmeter at the moment to say if it gives 14-15 V to the battery (but I guess it's not)

[volvodspec]

can you still start it easy?

you could also check the brown wire near the lightshandle on the steering collumn, if that gets loose you also get weird light problems

[MCHUDD]

Hi Fel.
It could be that your voltage regulater in the altonater needs renewed.
I am shure that some of the tech guys will come up with other sugestions to help you.
Cheers Mark.

[Fel]

No, I can't start it at all now, battery is discharged.
Will try tomorrow to check it in the daylight the voltage coming from alternator.

Thank you for your replies!

btw, I was searching in this forum similar problems and found this quote:

"the battery light also takes its feed from the 12V main supply to the other warning lamps, so if that's dicky then the battery light won't be working correctly, cos IIRC it works on a balance of voltages and if one side is missing then it'll light up."

It is strange, that battery light is not working.. I don't get it.

EDIT: that light controller works fine, so I don't think, that problem is in that.

[classicswede]

A good pointer would be to start the engine then disconnect the battery wires. The engine should continue to run if it is charging. If teh engine dies then pretty much either the alternator is not working or one of teh wires going to it is broken.

[Fel]

A good pointer would be to start the engine then disconnect the battery wires. The engine should continue to run if it is charging. If teh engine dies then pretty much either the alternator is not working or one of teh wires going to it is broken.

thanks for the advice.

result: alternator kaput.

when I hit the throttle one moment it started charging (12 V), but only for a few moments. Later engin ran only on battery (12 V).
Disconnected the battery "-" wire and angine stopped.

Will try to take the alternator to service, I think it is better to fix this one (if possible of course), than to buy 2hand and wait for that to stop working.

EDIT: battery warning light still not working. It's "on" only when ignition is "on" but engine is not started.
Question: What is it doing there?

[Fel]

can you, please, tell me, what kind of alternators ar used with 1.7 carb engines?
it's about mounting points.

[nomead]

I have repaired the alternator in three different cars:
Seat Toledo -98 1.9D at about 250000 km (Bosch)
Seat Toledo -96 1.9D at about 315000 km (Bosch)
Volvo S40 -98 1.9TD at about 325000 km (Valeo)

Haven't had to touch my 340 or 360 alternators yet.

In all cases they didn't work due to worn out brushes. When I repaired the first one, I just didn't know enough and bought the whole regulator, that comes with new brushes installed. For the second and third ones I found new brushes and replaced just those. It wasn't an easy job though, mostly because the regulator is usually built so that it is easy to mass produce and some parts are protected from corrosion with some elastic resin (maybe silicone?) that is sometimes a bit hard to scrape off. But since they're basically just a piece of graphite carbon with a wire attached, the whole thing cost maybe one euro to replace.

Anyway the local Motonet sells the regulator+brush assembly for B172 "Paris Rhone" alternator for 13.50 euros. That should be easy enough to change, instead of swapping the whole alternator.

And here's a picture of some random (very worn out) brushies :

brushes.jpg (53.18 KiB) Viewed 4799 times

[Fel]

so, it was the second type of mounting, if it makes sense to anybody
I have changed the alternator, haven't checked yet, what was wrong with that and here it goes again.. alternator is charging the battery, but when I switch the ignition on, battery lamp is off. what is the reason?

[volvodspec]

so without a running engine and ignition on the battery warning light is off?

in that case, the warning light is broken

[Fel]

so without a running engine and ignition on the battery warning light is off?

in that case, the warning light is broken

yes, that's right, but before changing the alternator it was working.