Alternator- New Exciter Resistor Still No Charge!!
12-21-2002, 01:40 PM
#16
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Let me preface my $0.02 with the fact that I didn't read this whole thread. Me bad.
I was pulling my hair out with a charging problem. After cleaning all current path connections, changing the battery, regulator, then the alternator, testing all current pathways for voltage drop / resistance... no luck.
Even though my voltmeter registered something and the charging warning lamp illuminated before starting the car, the darn thing wouldn't charge.
I figured that the warning lamp wasn't enough to excite the field and the resistor in that circuit must be open. I simply ran a wire from keyed power through a 68 ohm 2W resistor to the field wire on the alternator.
The voltmeter still doesn't register full voltage (always a couple volts low), but it is always 14 volts at the battery and the lights are bright. Perhaps not an elegant solution, but it got me back behind the wheel & was a more attractive alternative to removing the pod, etc.
I was pulling my hair out with a charging problem. After cleaning all current path connections, changing the battery, regulator, then the alternator, testing all current pathways for voltage drop / resistance... no luck.
Even though my voltmeter registered something and the charging warning lamp illuminated before starting the car, the darn thing wouldn't charge.
I figured that the warning lamp wasn't enough to excite the field and the resistor in that circuit must be open. I simply ran a wire from keyed power through a 68 ohm 2W resistor to the field wire on the alternator.
The voltmeter still doesn't register full voltage (always a couple volts low), but it is always 14 volts at the battery and the lights are bright. Perhaps not an elegant solution, but it got me back behind the wheel & was a more attractive alternative to removing the pod, etc.
12-21-2002, 11:11 PM
#17
Racer
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Thanks for all the ideas. I'll get at it tomorrow. I have not removed the engine ground and cleaned it so that will be the first thing to do. Thanks again Jim, Wally, & Old.
12-22-2002, 01:24 PM
#18
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I just spent a few hours out in the cold. I cleaned the engine ground- nothing. I pulled the pod and checked for power to the resistor. There is power on one end of the resistor so I connected a wire from the exciter terminal on the alternator to the other end of the resistor. Fired it up and still no charge.
My side marker lights are 4 watts- perhaps becuase it is euro. I did the light bulb test agian and nothing happened, although there was no one to rev the engine. During all of this I never got the discharge light on the cars volt meter to come on.
I bet the wires I used in the light tester are too small gauge. They are quite dinky. The gauge I used form the exciter terminal to the resistor is roughly the same that was originally hooked up to the alternator.
I'm about to push this car into a river.
My side marker lights are 4 watts- perhaps becuase it is euro. I did the light bulb test agian and nothing happened, although there was no one to rev the engine. During all of this I never got the discharge light on the cars volt meter to come on.
I bet the wires I used in the light tester are too small gauge. They are quite dinky. The gauge I used form the exciter terminal to the resistor is roughly the same that was originally hooked up to the alternator.
I'm about to push this car into a river.
12-22-2002, 05:03 PM
#20
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I just tried using one of those white 12' extension cords. I twisted both wires on the cord together. Connected one end to the resistor and the other to the exiter terminal and got nothing. While the car was running I took the multi meter and checked for power to one end of the resistor. Power was there. I put the multi meter directly to the other end of the resistor and it showed nothing. I tried raising the engine speed and nothing happened. My multi meter only shows 1.5k ohms and using that the needle on the multi meter went to the end of the scale. I did all this was with the multi meter connected directly to the resistor. Should there be voltage coming through the exciter side of the resistor? Also, one of the little bulb sockets on the back of the cluster right by the volt meter is missing. This wouldn't do anything would it?
12-22-2002, 06:05 PM
#21
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Flormat,
It sounds like you have a defective resistor or it is not installed properly. You should see 12V on a voltmeter on both sides of the resistor as long as the key is on. You should measure the same at the exciter terminal on the alternator under the same conditions.
Power is on the other side of the resistor & light (which are in parallel). The light goes off when the alternator begins to charge because the exciter teminal is no longer at ground potential.
Either try what I recommended above, or if you don't have a good resistor, just start the car & tap a power wire to the exciter terminal (but don't leave it attached). It should come up to 14 volts at the battery & stay there until you shut the car off.
It sounds like you have a defective resistor or it is not installed properly. You should see 12V on a voltmeter on both sides of the resistor as long as the key is on. You should measure the same at the exciter terminal on the alternator under the same conditions.
Power is on the other side of the resistor & light (which are in parallel). The light goes off when the alternator begins to charge because the exciter teminal is no longer at ground potential.
Either try what I recommended above, or if you don't have a good resistor, just start the car & tap a power wire to the exciter terminal (but don't leave it attached). It should come up to 14 volts at the battery & stay there until you shut the car off.
12-22-2002, 06:39 PM
#23
Three Wheelin'
[quote]Also, one of the little bulb sockets on the back of the cluster right by the volt meter is missing. This wouldn't do anything would it? <hr></blockquote>
Shine a flashlight through the socket and look at the cluster to see what the light on that socket would indicate. There may be a spare socket, but nothing will illuminate on the cluster if this is the case.
If you haven't done so, please measure the reisitance (not voltage) to ground of the "-" wire which goes from the alternator to the pod. Measure with key on and key off. post the results and I'll compare it to my car. Let's see if the circuit is being completed. Also measure the 68 ohm resistor out of the car and without touching the meter probes with your bare hands. Let's see if it's still in spec.
BTW, there is a big difference in a couple of ohms in this circuit. I had a resistor which measured 71 ohms, charging was about 13v. I put in a replacement 68 ohm and charging went to 14v. If you're too far out of spec, you'll have trouble. If it were me, I'd concentrate on the car wiring and not on the alternators themselves. I think you have established that the alternators should work., The car is at fault, IMHO.
Do you have the wiring diagram for your pod and alt. circuit? If not, email me at gh@rennlist.com
post here that you did, as I rarely check that email. I'll send the proper pages to you via email.
Greg
Shine a flashlight through the socket and look at the cluster to see what the light on that socket would indicate. There may be a spare socket, but nothing will illuminate on the cluster if this is the case.
If you haven't done so, please measure the reisitance (not voltage) to ground of the "-" wire which goes from the alternator to the pod. Measure with key on and key off. post the results and I'll compare it to my car. Let's see if the circuit is being completed. Also measure the 68 ohm resistor out of the car and without touching the meter probes with your bare hands. Let's see if it's still in spec.
BTW, there is a big difference in a couple of ohms in this circuit. I had a resistor which measured 71 ohms, charging was about 13v. I put in a replacement 68 ohm and charging went to 14v. If you're too far out of spec, you'll have trouble. If it were me, I'd concentrate on the car wiring and not on the alternators themselves. I think you have established that the alternators should work., The car is at fault, IMHO.
Do you have the wiring diagram for your pod and alt. circuit? If not, email me at gh@rennlist.com
post here that you did, as I rarely check that email. I'll send the proper pages to you via email.
Greg
12-22-2002, 10:55 PM
#24
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Greg, I have sent you an email.
I had earlier shined light through the socket and it illuminates a word through the face, but it is 1 of 2 bulbs that light up the same word I figured I did not need it.
I had earlier shined light through the socket and it illuminates a word through the face, but it is 1 of 2 bulbs that light up the same word I figured I did not need it.
12-23-2002, 12:01 AM
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Flormat,
If you have power at one end of the resistor and not the other end, either the first end is not really connected (e.g. a plastic washer in there), or you have a defective resistor. Try the thing I detailed before; tap the exciter terminal with a hot wire & your system should begin to charge. If not, the problem is in the [+] or ground circuit!
If you have power at one end of the resistor and not the other end, either the first end is not really connected (e.g. a plastic washer in there), or you have a defective resistor. Try the thing I detailed before; tap the exciter terminal with a hot wire & your system should begin to charge. If not, the problem is in the [+] or ground circuit!
12-23-2002, 12:26 AM
#27
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I hope that this doesn't offend you, but if you don't take the time to understand how the circuit works, and to perform the tests suggested, you need to take the car to someone who does understand how the exciter circuit works.
If you followed the suggested tests, and disconnected the exciter wire from the alternator, it doesn't make a damn bit of difference WHAT the exciter circuit in the car is doing, or how it is hooked up or what the resistor is.
If you followed the suggested tests, and disconnected the exciter wire from the alternator, it doesn't make a damn bit of difference WHAT the exciter circuit in the car is doing, or how it is hooked up or what the resistor is.
12-23-2002, 04:02 PM
#28
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That doesn't offend me Wally. I feel I do have a fairly descent grasp of how it works now- I got a hold of some documents called "Charging Circuits" from a book at the library. Between that and the information provided on this post I have learned a lot. I tried all the tests out out above and I believe I have a short in the + or ground circuit as mentioned. I think this because when I supplied 12 volts directly to the exiter circuit the connection sparked and smoked, all of the lights went dim and the volt meter in the dash dropped to the "car off" position, and still no charge. When I went to the place where I had the alternators tested and they were completely stumped. They said if I wanted to leave it with them for a while they would see what they could find. They did a few short tests like the ones suggested in this post but with no better luck.