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Alternator Question

01-22-2007, 06:16 PM
i have a question
i just had a new alternator put in my 1995 ford probe gt about 2 days ago. i was driving and it was icy and i gave it gas and it spun my tires and my engine rpm's went to about 6-7k.

now my battery meter or electrical meter near the speedo says low and wont go up. is it my alternator again or my battery?

01-23-2007, 07:57 PM
It isn't possible to know, from the information provided. Do you have access to a multimeter? If so then take some voltage readings, as follows:

1. With the engine running, measure the voltage directly onto the battery terminal posts (not the connectors). You should expect to see thirteen-point-something volts, maybe as high as 14V and that tells you that the alternator is sending at least some charging current to the battery.

2. Now increase the revs, and the voltage should climb to around 14.2V and it should stabilise at that level regardless of any further increase in engine speed. That will tell you that the voltage regulator appears to working ok.

3. After leaving the vehicle parked overnight, measure the battery voltage next morning but before starting the engine. You should expect to see around 12.6V

If you have a problem with either alternator, regulator, or battery, then one or more of those readings will not be as expected and it should indicate the area where the problem is.

That's all assuming that you have access to a meter - without one you will struggle to do any meaningful fault-finding at all on the charging circuit.

01-23-2007, 09:01 PM
Also, check and see if the alternator belt is still correctly tensioned.

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