Electrical issues.... starter and alternator screwed?
Discussion
Searched on here and found so many threads, it's hard to sort through them, so I thought I'd add to it by starting another...
Charged battery up.
Ignition lights, fuel pump primes, relay in footwell clicks but starter does nothing.
Bump started car (pushed)
Car ran till battery ran out, then it died
Could it be that both the starter and alternator are screwed? Or is it something else?
Thanks for any help
Charged battery up.
Ignition lights, fuel pump primes, relay in footwell clicks but starter does nothing.
Bump started car (pushed)
Car ran till battery ran out, then it died
Could it be that both the starter and alternator are screwed? Or is it something else?
Thanks for any help
Did the battery take a proper charge? Your relays and ignition worked but not the starter. Charge the battery again and see if there's enough power to light the headlamps, if not then that is probably why the starter doesn't work. You could also check the 100amp fuse between the starter and alternator. Good luck.
ButtonIt said:
Car ran till battery ran out, then it died
This certainly suggests there's a problem charging the battery. This could be due to a faulty alternator or a blown 100A fuse in the alternator circuit.Does the car start if the battery is fully charged? If it does then the battery and starter are OK. If not, then you've got a problem with one or the other.
With the ignition off and some charge in the battery, how many volts are there across the alternator? There should be 12V across it indicating that it's connected to the battery. If there are 12V this suggests an alternator problem. If there is not 12V then the fuse in the cable between the alternator and battery has blown and needs to be replaced.
The battery is new and has been fully charged. When turning the ignition key there is no drain, just a light click from the passenger footwell and nothing else. Bump started fine and ran lovely until it just stopped, at the time it stopped there was no juice left in the battery (lights very dim, fans slow etc).
To test the alternator once you get the car started again, you'll need a multimeter to measure the voltage at the battery and at the alternator. Measure voltage between the alternator main output terminal and ground. This should be between 13.9 and 14.4V. Then measure again (also with engine running) across the battery. This should be above 13V.
A further test to check that the alternator works under high load conditions - Switch on headlights, heater fan and anything else that pulls significant current. Get someone to hold the engine revs at 2000 and recheck the voltage at the battery - it should still be above 13V.
Another factor to take into consideration is that the alternator is primed at start-up by the current running through the ignition warning lamp. Check that the warning light comes on before the engine starts and goes off when the engine has started.
Mike
A further test to check that the alternator works under high load conditions - Switch on headlights, heater fan and anything else that pulls significant current. Get someone to hold the engine revs at 2000 and recheck the voltage at the battery - it should still be above 13V.
Another factor to take into consideration is that the alternator is primed at start-up by the current running through the ignition warning lamp. Check that the warning light comes on before the engine starts and goes off when the engine has started.
Mike
OK,so a multimeter on the main output and ground shows 0.2 volts. (Incidentally, just below the alternator there is a small white cylinder that appears to be spliced into the wiring of the alternator. Is this a voltage test jack?)
Is the alternator and starter motor on the same circuit? Would they both be affected by the 100A fuse?
I did have a quick look at the fuse, but haven't jacked it up sufficiently to have a proper look yet (it's wet outside).
Is the alternator and starter motor on the same circuit? Would they both be affected by the 100A fuse?
I did have a quick look at the fuse, but haven't jacked it up sufficiently to have a proper look yet (it's wet outside).
My alternator's required the diode pack changing twice during my ownership. Both times with the engine switched off the shaft protruding through the pulley was mildly magnetic (attracted small spanner when place close to it). This leakage was puling the battery down causing all sorts of wierd things to happen. I also recall a whirring noise during running, good news was that local autoelectrician repairs for £20 a time.
ButtonIt said:
OIs the alternator and starter motor on the same circuit? Would they both be affected by the 100A fuse?
not AFAIK. The charging circuit from alternator to battery is "protected" by the 100A fuse, if present. I believe the starter motor circuit is unfused (it would have to be given the currents required to start the engine). ButtonIt said:
OK,so a multimeter on the main output and ground shows 0.2 volts.
Assuming you did this while the engine is running then your alternator is not working and so won't recharge the battery. Your car will run while there's enough charge in the battery. What's more, the fact that you did not measure 12 volts suggests the battery is not properly connected to the alternator either!When the car, including ignition, is off there should be approximately 12V across the battery and the alternator.
When starting the voltage across the battery will drop down as low as 9V but once running, if the alternator is working you should have over 13V across the battery and the alternator. If you have over 13V across the alternator but only 12V across the batter then the connection between the alternator and battery is faulty - first suspect is the 100A fuse.
I've had exactly this experience my self just a couple of weeks ago. I've bought an Accumate TestMate mini and using a cigar lighter adapter can see the voltages change before, during and after starting my Chim.
ButtonIt said:
(Incidentally, just below the alternator there is a small white cylinder that appears to be spliced into the wiring of the alternator. Is this a voltage test jack?)
Pass.ButtonIt said:
Is the alternator and starter motor on the same circuit? Would they both be affected by the 100A fuse?
No, they're on separate circuits. They both use the chassis for the ground but the alternator circuit goes to the battery via the 100A fuse while the starter goes to the battery via a solenoid.The solenoid connects the starter circuit only when you start the car while the alternator is always connected assuming the fuse has not blown.
ButtonIt said:
I did have a quick look at the fuse, but haven't jacked it up sufficiently to have a proper look yet (it's wet outside).
OK, finally I had the time to get under the car and have a good poke around.
First thing... the 100A fuse was corroded and then split in half when I took it off. That's the first issue, easy enough to fix. That would probably explain why the alternator wasn't charging back through.
Anyway, I took the starter motor out and tested the solenoid and motor spin on a battery, both were fine. I also did the tests that Steve Heath suggests in The Bible, using a multimeter, and they passed. The unit was clean and gunk free, so seems to be in good shape.
Now, I didn't have a chance to see if 12v was present at the positive battery connection because the battery was disconnected, but I'm thinking it'll be fine anyway, the chances are it's now donw to the ignition control wire and the immobiliser. Agree??
First thing... the 100A fuse was corroded and then split in half when I took it off. That's the first issue, easy enough to fix. That would probably explain why the alternator wasn't charging back through.
Anyway, I took the starter motor out and tested the solenoid and motor spin on a battery, both were fine. I also did the tests that Steve Heath suggests in The Bible, using a multimeter, and they passed. The unit was clean and gunk free, so seems to be in good shape.
Now, I didn't have a chance to see if 12v was present at the positive battery connection because the battery was disconnected, but I'm thinking it'll be fine anyway, the chances are it's now donw to the ignition control wire and the immobiliser. Agree??
Its not been unheard of that the supply wire to the starter from the imobiliser is long enough to cause a significant voltage drop, so the solenoid on the side of the starter simply wont engage. This is one of the issues the hot start kit resolves, as it stops the main part of the voltage drop with a much more direct volatge path. I think there are is also a relay in the imobiliser that can play up.
ButtonIt said:
But the 100A fuse sits after the starter motor in sequence from the battery. Surely if it was just the fuse then the motor would turn? (Happy to be proven otherwise though 
)
Are you sure? They 100A fuse on my Chim is between the alternator and battery +ve and that circuit is separate from the starter motor circuit. )Pretty sure, from what I saw on Monday...
Thick red cable to starter motor, thinner (but still quite thick) red cable from the same contact on starter motor going to one end of 100A fuse, other end of 100A fuse has a thick cable going up towards alternator.
The main positive terminal on the SM had two separate cable, both with lugs on, and a nut holding them tight together.
It's been like it since I've owned it, nothing's changed that I'm aware of...
Thick red cable to starter motor, thinner (but still quite thick) red cable from the same contact on starter motor going to one end of 100A fuse, other end of 100A fuse has a thick cable going up towards alternator.
The main positive terminal on the SM had two separate cable, both with lugs on, and a nut holding them tight together.
It's been like it since I've owned it, nothing's changed that I'm aware of...
If you're confident that the 100amp fuse has fixed the alternator, a quick text to rule out the earth strap is to run a jump cable clipped to the engine to the -ve terminal of the battery. A poor earth could explain why the starter is not engaging.
Also, if you've been taking the jumble of cables out around the battery it could be that something has unplugged. That would explain the click of a relay with no action.
(I've had both of these issues before!)
Also, if you've been taking the jumble of cables out around the battery it could be that something has unplugged. That would explain the click of a relay with no action.
(I've had both of these issues before!)
Gassing Station | Chimaera | Top of Page | What's New | My Stuff