resistance as small as 0.02 ohms
would results in a 3 volt drop in a
typical 150 amp starter circuit.
(150 amps x 0.02 ohms =3 volts).
Keep in mind that voltage with the
key on and voltage with the engine
running are not the same. With the
ignition on and the engine off
(battery voltage), voltage should
be approximately 12.6 volts. With
the engine running (charging
voltage), voltage should be
approximately 14.0 volts. Measure
voltage at the battery with the
ignition on and then with the
engine running to get exact
measurements.
Voltage, measuring
Connect digital multimeter negative
lead to a reliable ground point on car.
Note:
The negative (-) battery terminal is
always a good ground point.
-
Connect digital multimeter positive
lead to point in circuit you wish to
measure.
If a reading is obtained, current is
flowing through circuit.
Note:
The voltage reading should not deviate
more than 1 volt from voltage at the
battery. If voltage drop is more than
this, check for a corroded connector or
loose ground wire.
Electrical System - General
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Summary of Contents for 1999-2005 M3
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