Testing; Road Service; On-Engine Testing; Starter Cranking Circuit Test - Ford VSG-411 Service Manual

05-4
Startina Svstem 05-4
TESTING
Road Service
On Engine Testing
On road service calls, connect a booster battery to the
system for cases of a starter that will not crank the engine
or a starter that cranks the engine very slowly. If the starter
does not turn the engine over, even with the booster
battery attached, refer to the following tests.
Be certain
that correct battery polarity is observed when using a
booster battery; positive to positive, and negative to
negative connection of the auxiliary cables.
Starter Cranking Circuit Test
These tests will determine whether or not there is
excessive resistance in the cranking circuit. Make each
test connection as shown. While cranking the engine,
observe the voltage drop reading for each test.
Disconnect and ground the high tension lead from
the ignition coil to prevent the engine from starting.
Connect a remote control switch between the battery
terminal of the starter relay and the S terminal of the
relay.
STARTER CRANKING CIRCUIT TEST
The voltage drop in the circuit will be indicated by the
voltmeter (0 to 2 volt range). Maximum allowable
voltage drop should be:
1.
With the voltmeter negative lead connected to the
starter terminal and the positive lead connected to the
battery positive terminal (Connection No. 1) 0.5 volt.
2. With the voltmeter negative lead connected to the
starter terminal and the positive lead connected to the
battery terminal of the starter solenoid (Connection
No. 2) 0.3 volt.
3. With the voltmeter negative lead connected to the
battery terminal of the starter solenoid and the
positive lead connected to the positive terminal of the
battery (Connection No. 3) 0.2 volt.
4. With the voltmeter negative lead connected to the
negative terminal of the battery and the positive lead
connected to the engine ground (Connection No. 4)
0.1 volt.