Electrical Crisis

[Combat 911]

Okay, so I just dropped the motor in my '83 SC to replace some leaky oil seals...

A few days after having it back and running, my tachometer started jumping around at very random and occasional times while driving. At times it would die, like its ground was losing a connection. Then, the battery charge idiot light came on. This would happen for a few seconds, then everything would bounce back to normal.

This morning, the battery was dead.

I checked the battery terminals, which were clean and tight. I disconnected/reconnected the battery with no changes.

I'm thinking of a few possibilities... 1) The alternator was dieing. 2) The regulator died. 3) I have a bad ground strap--maybe the transmission to chassis? or 4) the battery was dieing, not taking a charge, and finally crapped out.

Help!

[targa80]

A bouncing tachometer is indicative of a charginging system problem. Do a search on bouncing tach there have bee several good threads on troubleshooting this problem.

[McDaniel]

9 times out of 10 a bouncing tach is caused either by a bad ground or a bad vr (as you indicated you suspected) I'd check
those first.

[RoninLB]

also..

the dizzy sends a pulse to the CD box.. the CD has a circuit that shapes the pulse to a signal for the tach