[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: 89 100 Wagon charging system woes :-(


>From your test description, it sounds like the ground from
the alternator, through the mounting bracket on the engine,
through the engine block, through the braided ground cable
from the drivers side engine mount bracket to the body,
through the body and over to the negative battery terminal
is ok. 

The alternator output cable, the battery positive cable and
the jump start cable all connect at the starter terminal as
you know. It sounds like either the positive end of the
battery terminal connector has internal corrosion or the
other end of the battery positive cable with the big lug
that bolts to the starter has a lousy connection between
the wire strands and the lug. I would cut off the positive
battery terminal from the cable  at the battery end and
make sure the bare wire strands don't have that green
corrosion stuff wicked up several inches of the cable. This
could have happened at the starter end of this cable as
well. Your test with the jumper cables should verify this
cable as being the problem.

I realize that  you measured the resistance between the
positive battery cable and the jump start terminal but how
did you get a reading of 0.000, most Multimeters are only
good to 0.1 ohm resolution, and many are not very accurate
down in the lower ranges. Going to 0.001 ohm resolution
usually requires a 4 terminal meter. Does your meter allow
you to zero out the resistance of the test leads? It only
takes a  resistance of 0.02 ohms with 70 amps flowing to
cause the voltage drop you described. Sometime under no
load conditions things seem ok.

Scott M.
89 200TQ
> Test Conditions:
>  Car running at idle.
>  Multimeter shows 14.0 volts at Jump Start post under the
> grounded to the Intake Manifold, Strut Bolt or Ground of 
> Battery post.  Yes I ran a wire all the way back to the
> ground just to be sure.
>  Multimeter shows 12.66 at Battery positive post when
grounded to
> the Intake Manifold, Strut Bolt or Ground of Battery
>  Thought this odd, so I ohmed out the connection from the
> post to the Jump Start post and it showed 0.000.
Some text deleted.....