[tbird635]

9v or less is either a ground problem/voltage drop or a battery . I'd bet battery.

[Gary M.]

Originally posted by timandsam:
Is it possible that this is my entire problem? I am going to pick up a new battery tomorrow.

Probably is. Contrary to popular myth, an alternator will not function on a battery with weak or dead cells. Your battery has two weak/dead cells.

[onesillynotch]

Originally posted by Gary M.:

Originally posted by timandsam:
[b] Is it possible that this is my entire problem? I am going to pick up a new battery tomorrow.

Probably is. Contrary to popular myth, an alternator will not function on a battery with weak or dead cells. Your battery has two weak/dead cells. [/b]

Gary

Why can they run if you pull the battery out?

Matt

[b-blown]

Originally posted by onesillynotch:

Originally posted by Gary M.:
[b]

Originally posted by timandsam:
[b] Is it possible that this is my entire problem? I am going to pick up a new battery tomorrow.

Probably is. Contrary to popular myth, an alternator will not function on a battery with weak or dead cells. Your battery has two weak/dead cells. [/b]

Gary

Why can they run if you pull the battery out?
Matt [/b]

or why can they run when boosting a dead battery and you drive it for 20min to recharge it ?

[tbird635]

it'll run but the voltage will spike wildly, possibly frying the regulator , alternator diodes, computer, ignition module, etc....

It needs a sufficient load that will absorb the spikes , sort of like a capacitor.

[b-blown]

Originally posted by tbird635:
it'll run but the voltage will spike wildly, possibly frying the regulator , alternator diodes, computer, ignition module, etc....

It needs a sufficient load that will absorb the spikes , sort of like a capacitor.

we were responding to this statement

Probably is. Contrary to popular myth, an alternator will not function on a battery with weak or dead cells. Your battery has two weak/dead cells.

[CruzNlife1]

I just chased this problem on my forklift, battert was fine. One day it was completely dead. Jumped it and it started, batt voltage at alt was about 8 volts. Ran a charger on it for a day, barely had enmough power to crank, and wouldn't rev if you did jump start it. Bypassing the regulator held it around 16 volts. Than back to 8. Replaced battery, everything is fine. Definitly sounds like the battery

[timandsam]

Ok so I put he new battery in... when istarted the car the voltage at the alternator was at 13.9v. The voltage slowly crept down to 13.75v. The voltage stayed between 13.4 and 13.8 then for about 5 min.

After 5min the voltage dropped down to 11.7v and you could hear less load on the engine. When I revved it the voltage went back to13.8 and then dropped back to 11.7v at idle.

What now? Could the alternator be failing when its hot only? What tells the alternator to charge and to stop charging? It is internally regulated.

Any ideas?

Thanks,
Tim

[onesillynotch]

dont forget when the car got warm, more than likley the rpms dropped also!

[timandsam]

Idle is at about 1000rpm when warm