alternator intermittant problem?
 

Hi,

jumped in Paloma to drive down to Devon for a great weekend and half way there my battery died, with no warning from my charging light. the RAC guy identified the alternator and we duly inspected it. he took out the rectifier but could find nothing wrong. He put everything back together and it still didn't work.

so i got towed home, only to discover that my alternator is now working perfectly! damn. anyone have any idea what might be occurring here. i've had the car 4 years and it's been as reliable as.....as a porsche!

any thoughts most welcome.

thanks as always.

justin

Connections
 

I had the same problem. It was an internal ground wire. I bet it was just a loose connection.

when you say internal, what exactly do you mean? i have searched the front and back to check contacts on all wires, expecially grounds, but don't find anything amiss. Perhaps you mean internal to the alternator, ie taking it apart and investigating.

the mechanic did open up the alternator and spent quite a long time examining the wires, he was quite thorough.

someone mentioned the alternator wires somehow connected to the starter motor, not sure what this means or why, but i haven't checked into this option yet.

thanks in advance as always.

jusitn

Alt problems
 

I have a regulator that is mounted to the back of the alternator. The regulator was removed from the back of the alternator The ground connection from the regulator to alternator was the problem.

They bench tested the unit for 30 min and everything was ok. It cost me $30 to repair.

How is the battery? And battery cables? Sometimes batteries will check out OK with a conductance test, but fail in a load test.

i presume that the regulator is the same as the rectifier? the RAC mechanic referred to the unit with the brushes on as a rectifier, since this was the only thing he took off (from the back of the alternator) i presume we are talking about the same thing.

if we are, he looked at this pretty thoroughly and i presume reattached it properly. but he did admit that he couldn't test it to be sure.

as for the battery, it's about 2 years old, never been run down, until Friday, and from the 15 minutes or more that it took to run down (i first became aware of the problem when the cassette machine stopped playing) i suspect is okay. cables as far as i can trace them are all sound and well connected.

i think i will tear down the alternator myself and really inspect the solder of the connections and trace the wires as far as i can. i inspected the springs myself when the rectifier was off and they seemed good.

thanks goodness SCs don't have too many electrics, it's the only thing that ever goes wrong on my car.

thanks

i haven't had a chance to look at the car, but took it out for a test and now, although the alternator is charging, the charging light doesn't come on when i turn on the ignition. (it did when i started it up after being towed home!)
i think the bulb is okay and now suspect some wiring around the light bulb, could this be a potential problem, or is the light purely indicative, and not structural to charging. if that makes sense?

thanks

Does the charge light come on if you turn the key to the run position and not the start position?

If not your bulb is out and the bulb need to be good in order for the alternator to work properly.

test voltage
 

try a volt ohm meter across the battery terminals and run the car at 3000 rpm,,you should have around 13.7 to 14.7 voltsi think...do a search on the board for exact.....if lower then probably your alternator if higher then your voltage regulator

just to clarify what could be a confusing post i'll try and bullet point the problem from the beginning.

1. car working perfectly for 4 years

2. last weekend light came on as per normal on start up but whilst on motorway, the cassette player suddenly died and then the engine started spluttering. the battery was clearly being run down but during this time the light did not come on. the battery was dead by the time i pulled over and the car wouldn't start. mechanic couldn't identify anything wrong but suspected the regulator

now the fun starts:

3. two hours later after the tow home i turned the key to the run position and the light came on (ie it was working as normal), the battery had clearly recovered some energy and the car started easily and the light went out as you would expect. i checked the charge and it was charging. so at this point i thought the car seemed to have fixed itself. i checked for loose earths but couldn't find anything obvious.

4. yesterday, (the first chance i have had to test the car), the light didn't come on in the run position (or on start) but the car fired up and is charging.

i didn't make a good note of the charge rate but i did see high 14 going into 15 volts. perhaps this is too high and a clue to a faulty regulator.

(by the way, is the regulator the matchbox sized plastic part that also contains the brushes?)

so it looks to me like a faulty regulator, if 15volts is too high, but would that stop the light from working? or is the light to blame? or was the light blown by the high voltage?

i will try and do some more investigations tonight but appreciate any thoughts before i do. how easy is it to replace the charging light?

as always, many thanks for your thoughts


PS. since posting this i have now bought a new regulator as someone has told me that i could blow up my battery by overcharging it, and probably fry other things too. so will report back on the situation when i have fitted it.

hi,

i need a bit of help right now!!

i'm just installing a new Valeo regulator and it has two wires a blue one and a yellow one. the original unit only had the blue, so i can't see anywhere to attach the yellow one.

help!

on the valeo internal reg alternator the yellow reg wire goes on the male connector next to the + output lug.

The blue goes on a similar male right next to the regulator on the right side.

According to my supplier, the yellow wire is an earth. thr original regulators earthed through the bolts but this was considered inferior to a dedicated wire, so they have added the yellow earth on the new ones.

1st pic is replacement up-grade
2nd is factory stock 1988 911



http://forums.pelicanparts.com/uploa...1158240452.jpg


http://forums.pelicanparts.com/uploa...1158240468.jpg

Justin: What year is your SC?
Some '82's didn't have the ground wire from case to alternator. (Search for Porsche Tech. Bulletin on this) Do you have this ground wire?
Yes, brushes are inside the regulator.
Check the connections to the bulb and get a new one.
Check the Voltage across the battery when running, should be about 14V

now i really am confused.

one preson has told me that they think a ground wire is unlikely to be yellow and that they connected their yellow wire to B+ ie to the red wire! whereas the supplier says to the ground. and in teh photo both wires look yellow...though the left one looks more yellow..

i have checked and my alternator is an A14N11 with a big brown ground wire at D-. year of car is late 82, 83 model.

so do i connect the yellow wire on teh regulator to the Ground, or to the red?

perhaps part of my indecision is being caused by the fact that it's obvious where the blue wire fits. the female connector slots over the copper male blade. however, there is no equivalent male blade on the other side. so do i cut off the female part and crimp on a ring and slot it over the red terminal?

sorry i'm being a bit lame here, but i don't want to do it and put the whole thing back together again only to discover it doesn't work, or that i've blown the regulator, or something else,
thanks, not least because if the regulator isn't the problem i will still have an investigation on my hands.

many thanks for your patience.

Well after more investigations i can report that:

the forum is correct, yellow goes to B+.

the confusion arose because the spade connector on the 3.2 carerra alternator for which this regulator was designed looks like it is welded onto the alternator body (ie ground), but an electrical test reveals that it is indeed connected to the B+ terminal.

teh original 'single-wire' regulators are not supplied anymore, so apparently anyone with an 81-83 SC will not have the built in spade connector for this upgraded 'two-wire' regulator.

thus i will have to cut off the yellow spade connector and fit an eye connector for the B+ terminal.

i hope this helps someone in the future, and thanks for all your help.

I agree with you about being careful about connecting the yellow wire correctly.
Ronin's picture shows (And he says it is connected to a male Faston on that terminal)
Confirm this with another source. It may be that you have to get this special Faston clip that mounts under the nut on that terminal to hold the yellow wire.
Start a new thread: "Internal Regulator Question"

well, i finally got a free evening to sit down and have a go at sorting out Paloma, the first thing i did was take the dash instrument out and clean the connections around the bulb and

HEY PRESTO!

she works again!

bloody hell, all that effort replacing the regulator etc...