Re: repeated jump starting

[DeWitt Harrison <de@aztek-eng.com>]

On Sun, 03 May 1998 05:10:18 -0500, Daniel R. LeFebvre wrote:

>it seems that i've had to jump my car more times than seems acceptable
>lately.  even last summer there seemed to be a problem.  i did not have
>to ever jump it in the winter.  now that it is getting warmer again here
>in boston, i've noticed that my starts have been getting weaker, and
>finally tonight it was necessary to jump the car again.  the alternator
>is new, as is the battery, and i've been told that the electrical system
>is fine.  my question is this:  i think the after-run fan is draining an
>undue amount of power from my battery, and my short drives to work and
>back do not provide sufficient time to recharge the battery fully.  is
>there a way to stop the after-run effect of the fan and have it run only
>when the engine is running?  has anyone else suffered this problem and
>tried this rememedy?  thanks.

The after-run cooling will not be a problem for a healthy electrical system
unless it does not shut off in the prescribed amount of time - maybe 15 min.
The first thing to check is whether the connection between the alternator and
the battery is good. There is a crimped connection at the firewall underneath
the carpet on the passenger side which sometimes goes bad and does not
allow the battery to charge properly. Make a voltage measurement between
the alternator output (the front battery access terminal is a convenient
place) and the battery positive terminal. Do this test with a load on the
system such as the cooling fan running and the A/C blower on high. If you
see more than a few tens of millivolts, the crimp could be bad. (While you're
there, also make the same voltage measurement from the alternator housing
to the battery negative terminal to check the ground side connections.)

If these check OK and the alternator output voltage is adequate, you will
need to dig deeper. What kind of shape is your radiator in?

DeWitt Harrison
Boulder, CO
88 5kcstq