alternator woes.
01-22-2018, 04:32 PM
#17
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Thread Starter
Jeff --
-- Does the charge light come on when you turn the key to "run" prior to engaging the starter? The bulb illuminates because of the difference in potential between the 15 (true when key in "Run" or "Start" positions, and the exciter circuit in the alternator itself. With added resistance or a broken wire, the lamp will be dim or not illuminate at all. If the light stays on after the engine has started, continue...
-- Put a volt meter on the exciter lead at the alternator, reference to ground. With key on and engine not running, you should see at least 6 volts or so there. Much less or nothing means there's extra resistance or a break (respectively...) in the exciter circuit from the dash.
Circuit description for testing:
-- Circuit travels from the 15 circuit through the lamp-or-resistor (in parallel in the cluster), illustrated on wiring diagram X at circuit index 38. Exits from the 15 bus at CE connection H7, to terminal 3R on the cluster, out from connection 1 on the cluster and back to CE connection H8, With key on and engine not running, lift the 14-pin in the engine bay, and test for battery voltage at CE connections H7 and H8. If you don't see that, reseat the cluster connectors and test again. These connections are documented on wiring diagram X, for those playing along at home.
The circuit continues on sheet 1 at circuit index 2, where it exits the CE panel at Z6 and comes right back at Z1 (black), then out again at O8 (blue). With the 14-pin lifted, you should see battery voltage at all of those with key in "run" position but not started. Plug the 14-pin back in, and you should see voltage reduce some to somewhere around 6 volts (depends on alternator and regulator). If you still see battery voltage, there's an open circuit/break in the wire between here and the alternator. Grounding any of these pins with key in "run" and engine not started should illuminate the dash indicator.
The circuit continues to the 14-pin connector to pin 1 (blue) in the bottom half. Again, battery voltage with the connector open and key in "run" position, but engine not started. Grounding any of these pins with key in "run" and engine not started should illuminate the dash indicator. With the 14-pin connected, the voltage should drop to around 6 Volts or so. Hard to test without very carefully removing the connector cover with the connector assembled (else risk the wires popping out of the upper connector body...)
The top half of the 14-pin connector pin 1 (blue) is the exciter wire to the alternator. At the alternator end, with 14-pin connected, you should see the same maybe 6 Volts as you saw at the 14-pin connector pin 1. With the exciter lead lifted from the alternator, you should see battery voltage with key in "run" position but not started. Grounding the open lead should illuminate the dash indicator.
Once everything is reassembled and working correctly, voltage at the exciter terminal on the alternator should read about 6 Volts with the engine not running but key in "run" position. The dash indicator should be illuminated. Once the engine is started, the voltage at the exciter terminal should rise to equal battery voltage, and the dash indicator should go out. If all this happens correctly right up to the part where the exciter voltage comes up and the light goes out, but doesn't make it that last step, your alternator isn't cutting it. (that's why I put this test step up at steps 1 and 2...)
HTH!
-- Does the charge light come on when you turn the key to "run" prior to engaging the starter? The bulb illuminates because of the difference in potential between the 15 (true when key in "Run" or "Start" positions, and the exciter circuit in the alternator itself. With added resistance or a broken wire, the lamp will be dim or not illuminate at all. If the light stays on after the engine has started, continue...
-- Put a volt meter on the exciter lead at the alternator, reference to ground. With key on and engine not running, you should see at least 6 volts or so there. Much less or nothing means there's extra resistance or a break (respectively...) in the exciter circuit from the dash.
Circuit description for testing:
-- Circuit travels from the 15 circuit through the lamp-or-resistor (in parallel in the cluster), illustrated on wiring diagram X at circuit index 38. Exits from the 15 bus at CE connection H7, to terminal 3R on the cluster, out from connection 1 on the cluster and back to CE connection H8, With key on and engine not running, lift the 14-pin in the engine bay, and test for battery voltage at CE connections H7 and H8. If you don't see that, reseat the cluster connectors and test again. These connections are documented on wiring diagram X, for those playing along at home.
The circuit continues on sheet 1 at circuit index 2, where it exits the CE panel at Z6 and comes right back at Z1 (black), then out again at O8 (blue). With the 14-pin lifted, you should see battery voltage at all of those with key in "run" position but not started. Plug the 14-pin back in, and you should see voltage reduce some to somewhere around 6 volts (depends on alternator and regulator). If you still see battery voltage, there's an open circuit/break in the wire between here and the alternator. Grounding any of these pins with key in "run" and engine not started should illuminate the dash indicator.
The circuit continues to the 14-pin connector to pin 1 (blue) in the bottom half. Again, battery voltage with the connector open and key in "run" position, but engine not started. Grounding any of these pins with key in "run" and engine not started should illuminate the dash indicator. With the 14-pin connected, the voltage should drop to around 6 Volts or so. Hard to test without very carefully removing the connector cover with the connector assembled (else risk the wires popping out of the upper connector body...)
The top half of the 14-pin connector pin 1 (blue) is the exciter wire to the alternator. At the alternator end, with 14-pin connected, you should see the same maybe 6 Volts as you saw at the 14-pin connector pin 1. With the exciter lead lifted from the alternator, you should see battery voltage with key in "run" position but not started. Grounding the open lead should illuminate the dash indicator.
Once everything is reassembled and working correctly, voltage at the exciter terminal on the alternator should read about 6 Volts with the engine not running but key in "run" position. The dash indicator should be illuminated. Once the engine is started, the voltage at the exciter terminal should rise to equal battery voltage, and the dash indicator should go out. If all this happens correctly right up to the part where the exciter voltage comes up and the light goes out, but doesn't make it that last step, your alternator isn't cutting it. (that's why I put this test step up at steps 1 and 2...)
HTH!
- Does the charge light come on when you turn the key to "run" prior to engaging the starter? The bulb illuminates because of the difference in potential between the 15 (true when key in "Run" or "Start" positions, and the exciter circuit in the alternator itself. With added resistance or a broken wire, the lamp will be dim or not illuminate at all. If the light stays on after the engine has started, continue...
=====
Yes, both glowing brightly. Key off
Was no floor jack at hangar available…so I FFW to here:
The circuit continues to the 14-pin connector to pin 1 (blue) in the bottom half. Again, battery voltage with the connector open and key in "run" position, but engine not started. Grounding any of these pins with key in "run" and engine not started should illuminate the dash indicator. With the 14-pin connected, the voltage should drop to around 6 Volts or so. Hard to test without very carefully removing the connector cover with the connector assembled (else risk the wires popping out of the upper connector body...)
===
Which I did. 0V at pin 1.
Start the car, its charging…turn on the headlights…it stops charging, and the OXY light dimly wavers. No charge light at the voltmeter
So….I waited for a jack…
-- Put a volt meter on the exciter lead at the alternator, reference to ground. With key on and engine not running, you should see at least 6 volts or so there. Much less or nothing means there's extra resistance or a break (respectively...) in the exciter circuit from the dash.
=====
0v
I have continuity from alternator exciter post to upper pin 1.
With key on and engine not running, lift the 14-pin in the engine bay, and test for battery voltage at CE connections H7 and H8.
=====
H7 4v, H8 11v.
Z6 and comes right back at Z1 (black), then out again at O8 (blue)
=====
I have no Z plug (83 5spd), but O8in this test (key on, 14 plug open) is…4v
??
01-22-2018, 07:44 PM
#18
Chronic Tool Dropper
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- Does the charge light come on when you turn the key to "run" prior to engaging the starter? The bulb illuminates because of the difference in potential between the 15 (true when key in "Run" or "Start" positions, and the exciter circuit in the alternator itself. With added resistance or a broken wire, the lamp will be dim or not illuminate at all. If the light stays on after the engine has started, continue...
=====
Yes, both glowing brightly. Key off
=====
Yes, both glowing brightly. Key off
Pull connector H and read the voltage at the pins in the CE panel side with the connector lifted. You should see battery voltage at H7 with key in "run" position, engine not running; nothing at H8. FYI, the wire color in the harness side going to H7 is black, and per the WSM diagram there are three black conductors in the harness side there. Similarly at H8, the drawing shows three blue conductors on the harness side.
With the H connector still lifted, test the HARNESS side connector pins H7 and H8 for voltage, referenced to ground. Share back your readings please. We are looking for the source of the voltage that's causing the charge light to be on.
Looking at Sheet X at rung 37 (rung numbers across the bottom...), H7 should be battery voltage with key in RUN position. It's tied to circuit 15 from the "15" contact in the ignition switch, 15 In the switch connects to 30 in the switch with key in run or start positions (sheet III rungs 1 - 4). The 30 rail gets primary un-fused power supply from battery positive (via the battery-to-starter, starter-to-alternator, alternator-to-jump-post feeders, and the 3 x 10 ga feeders from the jump post to the rail "30" power rail at the CE panel. 30 to the ignition switch from the rail is via CE panel connection A2, red. Ignition switch terminal 15 returns from the switch at A4 and A5 in parallel, black. Switch is on diagram III, circuits at rungs 1 - 4). Power to the 30 rail is shown on diagram 1 at rung 6.
01-23-2018, 10:14 PM
#19
Chronic Tool Dropper
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For those holding their breath at home in sympathy, waiting for the next episode: I left Jeff in an airless hanger with a two-hour bottle to breath from. He has chewing gum wrappers to use as jumpers, about 3" of candle left for illumination (that uses up some of the remaining air...) and no way to get out until the alternator starts working again.
I also left him my cell number for emergencies. Imagine how surprised I was when the phone rang from a Santa Cruz exchange less than 30 secs after I PM'd the number to him. Anyway, we went through just a couple quick test steps and narrowed it down to what looks like a loose connection in the cluster. With only the air remaining, Jeff decided he was going to pull the cluster for a look. Haven't heard from him since...
I also left him my cell number for emergencies. Imagine how surprised I was when the phone rang from a Santa Cruz exchange less than 30 secs after I PM'd the number to him. Anyway, we went through just a couple quick test steps and narrowed it down to what looks like a loose connection in the cluster. With only the air remaining, Jeff decided he was going to pull the cluster for a look. Haven't heard from him since...
01-23-2018, 11:46 PM
#20
Rennlist Member
Thread Starter
Ya..well, there was one wiggly connector off of the dash foil replacement PCB kit...zip tied attempting to hold in place something with an angled edge is...well doesnt work well.
i wiggled it and volt meter would jump and go dead. Ah ha!
20min later had pot back attached..turned on car..
https://www.flickr.com/gp/28804666@N08/eM1m9j <--Videos of my pain
No, I have no pod illumination, I have not chased that down yet..Rogers kit solved ALL guage issues (none worked0 except OPG (bad sender) and tach (havent dug into that yet either), But for many weeks, thing worked fine...then charging went to random ****...on and off lights, sometimes only the OXY light and no voltmeter light, sometimes both, sometimes BRIGHT, sometimes dim, sometimes theyre both off and still not charging...alt was replaced 1wk ago..no change...
i wiggled it and volt meter would jump and go dead. Ah ha!
20min later had pot back attached..turned on car..
https://www.flickr.com/gp/28804666@N08/eM1m9j <--Videos of my pain
No, I have no pod illumination, I have not chased that down yet..Rogers kit solved ALL guage issues (none worked0 except OPG (bad sender) and tach (havent dug into that yet either), But for many weeks, thing worked fine...then charging went to random ****...on and off lights, sometimes only the OXY light and no voltmeter light, sometimes both, sometimes BRIGHT, sometimes dim, sometimes theyre both off and still not charging...alt was replaced 1wk ago..no change...