Battery / Alternator Warning Light and no charge
03-03-2019, 10:32 AM
#1
Instructor
Thread Starter
Battery / Alternator Warning Light and no charge
Hi Folks,
I've been doing lots of jobs on my 944 Turbo over the winter and managed to get the main engine jobs finished over the weekend so celebrated with the first ignition since last August!
However I found a few issues whilst I was doing some final jobs yesterday including a no-charge condition with the battery / alternator.
I ran the engine for a good 30-45 minutes and it the voltage meter was dropping pretty low and the alternator light was on constantly along with the ABS warning light (which I understand is usually down to low voltage).
This morning I cracked out my voltmeter and read 12.6V across the battery with the ignition off and about 12.1 - 12.2 with the ignition on...
I pretty annoyed as the alternator is a pain to get to on the turbo and I'd already replaced the regulator as preventative maintenance before I re-installed it.
I replaced the regulator with a BERU GER 004 and I made sure that I cleaned up the alternator and the electrical contacts before I'd put it back together.
I've heard sometimes that a new regulator won't work as it won't "follow" the tracks that the old regulator has made on the contact bearing? Is this the likely cause - I was also very careful when I fitted it to not break the brushes.
I'm going to check continuity of the cables on the alternator next and see if I get the same voltage reading that I do from the battery - the only problem is it is impossible to run the engine whilst testing the alternator on the turbo due to the amount of stuff that needs to be removed for access!
I'm hoping this isn't going to be another huge bill as I've been looking and can see that replacement alternators range anywhere from £150 - over £500...
Thanks!
I've been doing lots of jobs on my 944 Turbo over the winter and managed to get the main engine jobs finished over the weekend so celebrated with the first ignition since last August!
However I found a few issues whilst I was doing some final jobs yesterday including a no-charge condition with the battery / alternator.
I ran the engine for a good 30-45 minutes and it the voltage meter was dropping pretty low and the alternator light was on constantly along with the ABS warning light (which I understand is usually down to low voltage).
This morning I cracked out my voltmeter and read 12.6V across the battery with the ignition off and about 12.1 - 12.2 with the ignition on...
I pretty annoyed as the alternator is a pain to get to on the turbo and I'd already replaced the regulator as preventative maintenance before I re-installed it.
I replaced the regulator with a BERU GER 004 and I made sure that I cleaned up the alternator and the electrical contacts before I'd put it back together.
I've heard sometimes that a new regulator won't work as it won't "follow" the tracks that the old regulator has made on the contact bearing? Is this the likely cause - I was also very careful when I fitted it to not break the brushes.
I'm going to check continuity of the cables on the alternator next and see if I get the same voltage reading that I do from the battery - the only problem is it is impossible to run the engine whilst testing the alternator on the turbo due to the amount of stuff that needs to be removed for access!
I'm hoping this isn't going to be another huge bill as I've been looking and can see that replacement alternators range anywhere from £150 - over £500...
Thanks!
03-03-2019, 09:22 PM
#2
Addict
Rennlist Member
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If the old slip rings are badly worn I suppose you might have a few minutes of poor contact while the new brushes wear in, but not 45 minutes of runtime.
03-03-2019, 10:11 PM
#3
Rennlist Member
Have you tried looking for a specialist? I realize things may be very different there, but here was able to have my alternator completely rebuilt locally for ~$150. That is of course assuming that your alternator is where your issue lies.
03-05-2019, 06:16 PM
#5
Rennlist Member
If the light is on on the dash, then the field wire (the little blue one) is grounded (and most likely grounded properly though the field wire).
I think you just have to take the alternator out and have it tested. It's possible there's more of a problem than the regulator you replaced.
I think you just have to take the alternator out and have it tested. It's possible there's more of a problem than the regulator you replaced.
03-06-2019, 05:41 AM
#6
Instructor
Thread Starter
Thanks Guys - I'm away for a couple of weeks, so plan is to check out the alternator when I return and make sure everything was fitted correctly, check continuity etc.
Not sure how to test the alternator when it isn't attached to the car but will try and find a good local auto electrician - doesn't seem to be many around as I think most garages these days don't bother troubleshooting the alternator, they just replace it with a new item from what I can see.
Not sure how to test the alternator when it isn't attached to the car but will try and find a good local auto electrician - doesn't seem to be many around as I think most garages these days don't bother troubleshooting the alternator, they just replace it with a new item from what I can see.
03-06-2019, 06:56 AM
#7
Rennlist Member
Thanks Guys - I'm away for a couple of weeks, so plan is to check out the alternator when I return and make sure everything was fitted correctly, check continuity etc.
Not sure how to test the alternator when it isn't attached to the car but will try and find a good local auto electrician - doesn't seem to be many around as I think most garages these days don't bother troubleshooting the alternator, they just replace it with a new item from what I can see.
Not sure how to test the alternator when it isn't attached to the car but will try and find a good local auto electrician - doesn't seem to be many around as I think most garages these days don't bother troubleshooting the alternator, they just replace it with a new item from what I can see.
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03-08-2019, 09:24 AM
#8
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The usual electrical tests should be possible with the alternator in place. A good battery connection at B+ (the big screw terminal) on the alternator. Switched power on the D+ (the smaller screw terminal) , good ground. Check the voltage output engine running and not. 12.5V or so key on, engine off. 13-14V running.
In addition if you loosen the belt you should be able to feel the resistance of the alternator field if you light it up. Use the ignition switch or briefly connect a test lamp or a small jumper lead from the battery + connection to the switched power / D+ / the "other" terminal. The alternator should get hard to turn by hand. If it does not you probably have a bad voltage regulator or broken brushes.
Brushes are easily replaced for small money with a drill and a soldering gun or big soldering iron. Volvo or Merc brushes from the same era work fine.
You should be able to idle the car with the piping and whatnot off, otherwise connect test leads and replace what you need without clamps so you can start and idle.
In addition if you loosen the belt you should be able to feel the resistance of the alternator field if you light it up. Use the ignition switch or briefly connect a test lamp or a small jumper lead from the battery + connection to the switched power / D+ / the "other" terminal. The alternator should get hard to turn by hand. If it does not you probably have a bad voltage regulator or broken brushes.
Brushes are easily replaced for small money with a drill and a soldering gun or big soldering iron. Volvo or Merc brushes from the same era work fine.
You should be able to idle the car with the piping and whatnot off, otherwise connect test leads and replace what you need without clamps so you can start and idle.
03-08-2019, 12:29 PM
#9
Instructor
Thread Starter
The usual electrical tests should be possible with the alternator in place. A good battery connection at B+ (the big screw terminal) on the alternator. Switched power on the D+ (the smaller screw terminal) , good ground. Check the voltage output engine running and not. 12.5V or so key on, engine off. 13-14V running.
In addition if you loosen the belt you should be able to feel the resistance of the alternator field if you light it up. Use the ignition switch or briefly connect a test lamp or a small jumper lead from the battery + connection to the switched power / D+ / the "other" terminal. The alternator should get hard to turn by hand. If it does not you probably have a bad voltage regulator or broken brushes.
Brushes are easily replaced for small money with a drill and a soldering gun or big soldering iron. Volvo or Merc brushes from the same era work fine.
You should be able to idle the car with the piping and whatnot off, otherwise connect test leads and replace what you need without clamps so you can start and idle.
In addition if you loosen the belt you should be able to feel the resistance of the alternator field if you light it up. Use the ignition switch or briefly connect a test lamp or a small jumper lead from the battery + connection to the switched power / D+ / the "other" terminal. The alternator should get hard to turn by hand. If it does not you probably have a bad voltage regulator or broken brushes.
Brushes are easily replaced for small money with a drill and a soldering gun or big soldering iron. Volvo or Merc brushes from the same era work fine.
You should be able to idle the car with the piping and whatnot off, otherwise connect test leads and replace what you need without clamps so you can start and idle.
would like to see you test an alternator in place on a 944 Turbo.... the air intake system and boost pipes have to be removed to gain access to it and the electrical connections can only be accessed once the alternator is removed from its mounts.I've already replaced the regulator as mentioned in my original post but thanks for the advice.
03-08-2019, 07:28 PM
#10
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I've owned two of them. Yes, it's not easy but this is the life we chose.
How do you know your new regulator did not quit working? Brushes get broken? Newness is actually an indicator that some might be the problem, not that it cannot be.
Maybe the wires have come loose?
How do you know your new regulator did not quit working? Brushes get broken? Newness is actually an indicator that some might be the problem, not that it cannot be.
Maybe the wires have come loose?
03-09-2019, 08:47 AM
#11
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What ‘other’ jobs have you done? Are you sure that the alternator wiring is making a complete path. It goes from pos battery to the starter. Starter to alt. Alt to ground. Ground to negative battery.
when I got my project the guy who had it before me, who was obviously just trying to get it started so he could sell it, hooked up the large leads on the starter incorrectly...meaning different posts. The car actually started but didn’t produce any voltage. Eventually that incorrect connection fried the starter. Once hooked up correctly it was making 14.3-14.8.
when I got my project the guy who had it before me, who was obviously just trying to get it started so he could sell it, hooked up the large leads on the starter incorrectly...meaning different posts. The car actually started but didn’t produce any voltage. Eventually that incorrect connection fried the starter. Once hooked up correctly it was making 14.3-14.8.
04-22-2019, 07:05 PM
#12
Instructor
Thread Starter
I got a rebuilt Bosch alternator in a Lucas box with a test certificate print-out showing the actual test results from the alternator in the box. Everything has been replaced and it looks brand new so well chuffed and it also fixed my problem and showed a healthy voltage when running! I'm pretty sure that my rectifier / diodes were stuffed as if I recall correctly before the car was taken off the road the voltage wasn't stellar but is now showing a healthy 14v on the in-dash voltmeter.
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