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Re: Alternator...

To: Michael Graziano <mgrazian@ltcm.com>
Subject: Re: Alternator...
From: Paul Hunt <paul.hunt1@virgin.net>
Date: Sun, 19 Jul 1998 15:56:27 +0000
Michael Graziano wrote:
> 
> I think my alternator's shot.
> 
> I went to start my car yesterday, and the battery was dead.  I
> jumped the car,  and it ran fine (after I disengaged the jumper
> cables).  I drove it for an hour,  and let it idle afterwards for
> 10 minutes.  I went to start it 5 minutes later,  and the battery
> was still completely dead.  All electrical items run w/o the
> engine on enough to know that the battery ic connected.

Could be the battery connections/engine strap good enough to run other 
electrical 
bits but not start the car.  Could be the battery as described by others.  
Could 
be the starter circuit (ignition switch/relay/solenoid) not functioning 
correctly.

You say that other electrical circuits work OK.  If you turn the lights on, do 
they 
go out or stay on when you try to start the car?  If they go out than that 
points to 
the battery or the heavy current cable connections or the alternator.  If they 
stay 
on then that implies the starter circuit is at fault.

Jump the car and run the engine at 3,300 rpm with the headlights on.  Measure 
the 
voltage at the alternator terminals, you should see 14.0 - 14.4v.  If it is 
less than 
this the alternator/regulator is bad or you have a very big short on the output.

Now connect the voltmeter from the alternator positive to the battery positive 
and 
note the reading, then do the same negative to negative.  You should get 0.2v 
to 0.5v 
each side, anything higher indicates one or more poor connections in the 
charging/starting circuit, check the battery post connections, cable to body 
connection, earth strap to body and engine connections, and the brown circuit 
connections on the alternator and (usually) solenoid.

If all the above is OK then suspect the starter circuit, use the voltmeter to 
track 
the voltage through the ignition switch, relay and solenoid.  If all these are 
OK 
then it could be the starter contacts inside the solenoid.

PaulH.



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