142 guy
Member
- Joined
- May 31, 2014
- Location
- Saskatchewan, Canada
but in terms of applying field flashing - that means my alternator is still partially working for the time being? fundamentally, if it is NOT below the battery voltage static - i.e without car on - then the alternator is doing its job?
but at 13.4V with the car idling, the bottom line is that a new alternator is basically in my future? regardless of the brushes or regulator? shouldn't the voltage, ideally, be 14V at least?
Yes, the alternator is charging the battery. You do not need to mess around with field flashing because that is not your problem. If you want to try an acid test, with the engine running switch on the headlights, 4 way flashes, the heater fan, radio and any other electrical loads that you can think of. Watch the voltmeter. If the voltmeter drops to the battery voltage you know that the alternator has limited ability to supply charging current. This could be an internal alternator problem or it could be a wiring problem. If the alternator is able to maintain the voltage at 13.4 volts with all that load you are probably OK to go.
The 13.4 volt operating point is lower than ideal and may be a sign that the regulator may be out of spec, or damaged or that you have a nasty wiring problem. I don't think the 13.4 volt operating voltage confirms that a new alternator is mandatory. Since your brushes were not worn down a new regulator might fix the problem; however, I am more inclined to believe that you might have some wiring problems. I had an 1987 745 T which had the Volvo biodegradable wiring. I thought the charging system wiring was separate from the engine wiring harness. If you have the original charging system wiring you may have some issues there.