Component Tests and General Diagnostics
COMPONENT TESTSThe following component tests are used to diagnose starter motor concerns.
Starter Motor
WARNING: Always disconnect the battery ground cable at the battery before disconnecting the starter motor battery terminal lead. If a tool is shorted at the starter motor battery terminal, the tool can quickly heat enough to cause a skin burn. Failure to follow this instruction may result in serious personal injury.
NOTE: A protective cap or boot is provided over the battery input terminal on all vehicle lines and must be installed after repair. Be sure to disconnect the battery ground cable before repairing the starter motor.
Prior to carrying out the component tests check the battery to determine the state of charge. Carry out a load test of the battery. Refer to Battery for the test procedure.
Starter Motor Load Test
1. Disconnect the ignition coil connector from the ignition coil.
2. Connect the SABRE tester to the vehicle using the amperage lead clipped around the positive battery cable.
3. Measure the amperage of the starter motor while activating the starting system.
4. A correctly operating starter motor will draw from 130 to 190 amps of current at room temperature.
Voltage Drop Test
The following test procedures will be carried out with the starter motor on the vehicle.
Motor Feed Circuit
NOTE: Make all multi-meter connections at the component terminal rather than the cable or wiring terminal.
1. Disconnect the ignition coil connector from the ignition coil.
2. Connect a remote starter switch between the starter solenoid S-terminal and the battery positive (+) post.
3. Connect the positive (+) lead of the 73III Automotive Meter to the battery positive (+) post. Connect the negative (-) lead of the multi-meter to the starter solenoid M-terminal.
4. Engage the remote starter switch. The multi-meter reading should be 0.5 volt or less.
5. If the voltage at the M-terminal is greater than 0.5 volt, move the multi-meter negative (-) lead to the starter solenoid B-terminal and repeat the test.
6. If the voltage reading at the B-terminal is less than 0.5 volt, the problem is either in the connections at the starter solenoid or the starter solenoid.
7. Remove the wires at the starter solenoid B-, S- and M-terminals. Clean the connections and install the cables. Repeat Steps 1 through 5 above. If the reading is still higher than 0.5 volt at the M-terminal and 0.5 volt or lower at the B-terminal, the problem is in the starter solenoid. Install a new starter motor.
8. If the voltage taken at the starter solenoid B-terminal is greater than 0.5 volt, the problem is either the positive (+) battery cable connection or the positive (+) battery cable.
Motor Ground Circuit
NOTE: Make all multi-meter connections at the component terminal rather than the cable or wiring terminal.
A slow cranking condition can be caused by resistance in the ground or return portion of the cranking circuit. Check the voltage drop in the ground circuit as follows:
1. Disconnect the ignition coil connector from the ignition coil.
2. Connect a remote starter switch between the starter solenoid S-terminal and the battery positive (+) terminal.
3. Connect the positive (+) lead of a 73III Automotive Meter to the starter motor housing. The connection must be clean and free of rust or grease. Connect the negative (-) lead to the negative (-) battery terminal.
4. Engage the remote starter switch and read the voltage. The reading should be 0.5 volt or less.
5. If the voltage drop is greater than 0.5 volt, clean the negative (-) battery cable connections at the battery and chassis. Also, clean the engine ground cable connection at the cable mounting bracket. If the voltage drop is still excessive, repair or install a new battery ground cable.
Starter Drive Test
1. Remove the starter motor.
2. Secure the starter motor in a vise.
3. Connect the battery ground cable of a fully charged battery to the case of the starter motor.
4. CAUTION: Do not leave the positive lead of the battery connected to the starter motor S-terminal for more than 10 seconds. Failure to follow this instruction may result in damage to the starter or starter circuit.
Touch the positive lead from the battery to the S-terminal and verify that the starter drive ejects.
5. Remove the positive lead from the starter motor. The ejected starter drive should return to its original position.
6. If the starter drive does not eject and return to position, install a new starter motor.
7. Check the starter drive. It should turn freely in one direction, and positively engage to the armature when turned in the opposite direction. If not as specified, install a new starter motor.
No Load Test
The Starter No Load Test will identify open or shorted windings and a possible rubbing starter motor armature or bent starter motor armature shaft.
1. WARNING: Securely mount the starter motor to the bench when bench testing. The starter motor may move or jump when it is energized. Failure to follow this instruction may result in serious personal injury.
Connect a fully charged battery, a SABRE Tester and a remote starter switch to the starter motor. Connect the remote starter switch between the battery positive (+) post and the starter motor S-terminal. Connect the starter motor B-terminal to the battery positive (+) post. Connect the SABRE positive (+) terminal and negative (-) terminal to the corresponding battery post. Make sure that the battery and starter motor are grounded.
2. Engage the remote starter switch.
3. The starter motor should eject the starter drive and run smoothly. If the starter motor does not run smoothly, install a new starter motor.
4. While the starter motor is running, check the voltmeter and ammeter.
5. The amperage should be no more than 84 amps.
6. If the amperage is higher than 84 amps, install a new starter motor.