91RRC - Alternator won't charge battery - tachometer won't work now.

[jpcook]

91RRC
A month ago, driving along at night, the lights began to dim. Can't remember if the battery light was on or not. The car was laboring (due to low voltage?) and the wife and I made it to the middle of a busy highway. I would have guessed that the alternator died and then killed the battery on it's way out. Tachometer and speedometer were both working at the time. From the schematics: if the bulb on the instrument cluster dies or does not light, the alternator will not charge.
Put it on and installed a new battery and had the starter rebuilt. Battery light on at ignition and off almost immediately after start. Car runs! Tach does not function. Found another busy highway and it died at a semaphore, the battery exhausted. No light to indicate anything was wrong. Changed battery to a yellow top that works fine in my other Rover (Disco) and alternator will not charge it. Put the battery into Disco and it charged it right up.
Replaced wires and cleaned connections:
+ to starter
starter to firewall
firewall to alternator
- to frame
- to sheet metal and aux wires.
strap from sheetmetal to engine block.
Had alternator tested. I was told that is was not charging the battery. Took battery back to see if it was good. (it was) Had the alternator rebuilt again. (Cooked diodes?) Don't know. Charged battery. Tach worked, things looked good. Wife got a mile away when it died again with what appeared to be a dead battery.
Took the alternator back and had the re-builders check it out. They said it was not generating. Had it rebuilt AGAIN. Tach does not work,
Current Status:
Marriage on the rocks.
battery + to - : 12.02 volts (ignition off)
battery + to - : 11.65 volts (ignition & engine on)
battery + to alternator : 11.68 volts (ignition & engine on)


I need help/guidance/advice....what to look for?

[mearstrae]

It sounds as though your alternator is dead. It should be putting out at least 14.2V, and your tach is run by the alternator. So, you've actually answered your own question. Shop around, as these can be expensive.

'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

[badvibes]

Agree with mearstrae. Sounds like you need to be rid of that cursed alternator...

[rangerover]

Advance Auto has replacement alternators... they're at the college-kid level budget, and generally special order (24-48 hr shipping) . I'm currently running their replacement in my 1990 RRC, however, I must warn you that they are not of the highest quality. By that I mean they are significantly hit and miss. The moment I got mine I had to warranty it, then a week after the warranty one came in I had to return it again. Third time is the charm and the one that's currently under the hood is working like a champ.