8Mud
NAXJA Forum User
- Location
- Central Germany
88 XJ 4.0, CS 121 Delco Remey. In the last three months I`ve swapped in two of my, shelf alternators (spares)(pretty old but funtional). I´ve just picked up a new CS 130 (100 AMP). What I don´t want to do, is have it fail also, so I thought asking a few questions would be prudent.
I checked out two of the failed alternators, one had a bad diode, the other a very worn brush, the third I haven´t opened yet (maybe just bad luck, maybe something more sinister). I´m thinking the alternators were all pretty old, the best, by judging the brush wear, had maybe 60,000 miles on it.
Maintainance free battery, that holds a good charge (for days). But doesn´t seem to hold the 14-15 volts the charging system puts out. Usually tests at about 12.5 volts.
The field wire to the alternator, seems to have a line loss of about 1 volt, tests a volt lower than battery voltage. Could this cause the alternator to overcharge and maybe damage (overwork) it? Could the battery have a weak cell, causing the alternator to work a little too hard? All of the above?
Where might I check for the line loss in the field wire? I learned that troubleshooting, without a plan or destination under the dash, can cause more problems than it cures.
Grounds are clean and tight, no noticeable electrical gremlins. System seemed to charge, a little high (15 volts at startup), with all three of the alternators. But they all seemed to settle in at 13-14 volts after running awhile.
Any imput would be appreciated, I´m gonna be seriously upset if I smoke my new alternator.
Thanx MudderChuck
I checked out two of the failed alternators, one had a bad diode, the other a very worn brush, the third I haven´t opened yet (maybe just bad luck, maybe something more sinister). I´m thinking the alternators were all pretty old, the best, by judging the brush wear, had maybe 60,000 miles on it.
Maintainance free battery, that holds a good charge (for days). But doesn´t seem to hold the 14-15 volts the charging system puts out. Usually tests at about 12.5 volts.
The field wire to the alternator, seems to have a line loss of about 1 volt, tests a volt lower than battery voltage. Could this cause the alternator to overcharge and maybe damage (overwork) it? Could the battery have a weak cell, causing the alternator to work a little too hard? All of the above?
Where might I check for the line loss in the field wire? I learned that troubleshooting, without a plan or destination under the dash, can cause more problems than it cures.
Grounds are clean and tight, no noticeable electrical gremlins. System seemed to charge, a little high (15 volts at startup), with all three of the alternators. But they all seemed to settle in at 13-14 volts after running awhile.
Any imput would be appreciated, I´m gonna be seriously upset if I smoke my new alternator.
Thanx MudderChuck