AT 121 - Chapter 2 - Basic Electrical Principals



AT 121 - Chapter 12 Automotive Starters. Service, Diagnosis, and Inspection – PART A

Name: _________________________________________

Date: __________________________________________

WARNING! This lab will have you working with live batteries. Batteries are dangerous devices and can explode if shorted. Fire and explosion can result from carelessness! Batteries also contain sulfuric acid. If skin or eyes come in contact with acid or corrosion on the battery surface flush with water and seek medical assistance!

(It is important to remember a few things about how a vehicle starts. Most vehicles made after 1990 have a “clutch interlock” switch. This switch prevents a manual transmission vehicle from being starter in gear. However, it is important to make sure that the vehicle is in neutral and the parking brake is set before any type of automotive inspection or service is preformed! To start the vehicle the clutch must be fully depressed. Other vehicles with an automatic transmission must be in either neutral or park in order for the vehicle to start. On most manual transmission vehicles equipped with a clutch interlock the interlock switch is located above the clutch pedal. On most automatics the “neutral safety switch” is located on the transmission housing and is controlled by the shifter cable or rod.

( SECTION 1 Starter Inspection, Component Locations

Tools you will need:

Vehicle #1

Electrical Component Locator (Mitchell’s or Factory Shop Manual)

Wiring Diagrams (Mitchell’s or Factory Shop Manual)

Year _______________________ Make ___________________ Model ______________________

( Locate the following components on the vehicle and show them to your instructor;

( Battery Inspection (Cracks, Loose Terminals, Holdown, Corrosion) Results: ___________________________

( Starter Inspection (S wire, B wire, Ground) Results: ___________________________

( Ignition Switch (Wires, Connectors) Results: ___________________________

( Neutral Safety or Clutch Lockout Switch (Wires, Connectors) Results: ___________________________

( Starter Relay or Solenoid (Wires, Connectors) Results: _________________________

( Cable from battery to starter (Wire Damage, Connectors) Results: _________________________

Q(

Draw a simple schematic of a starting system;

B+ S

Name 6 components that could fail and cause a No-Crank scenario

_____________________________________________________________________________________________

_____________________________________________________________________________________________

_____________________________________________________________________________________________

Name 2 components that could fail and cause a No-Crank scenario, but the starter “runs” and makes noise.

_____________________________________________________________________________________________

Name 3 components that could fail and cause a noisy starter.

_____________________________________________________________________________________________

Name 3 components that could fail and cause a starter to get “stuck on”.

_____________________________________________________________________________________________

The ___________________ must be depressed on must manual transmission vehicles in order to start them.

On most automatics __________________________ is located on the transmission housing and is controlled by the shifter cable or rod.

On most manual transmission vehicles equipped with a clutch interlock the interlock switch is located

____________________________________________________________.

The “S” wire is the signal from the ______________________ switch. The “B” wire is ____________________

voltage at all times to the _________________________.

(Instructor’s Signature _________________________________________________________________

( SECTION 2 Starter Motor Removal

Tools you will need:

2001 Ford Windstar

Tool Board

WARNING: When servicing the starter motor or working underhood in the vicinity of the starter motor, note the heavy gauge input lead connected to the starter solenoid is hot at all times. Make sure the protective cap is installed over the terminal and is reinstalled after servicing.

( If needed lift the vehicle

( Disconnect the battery ground cable. Remove the bolts and lower the starter motor.

( Remove the caps, nuts and starter motor.

WARNING! DO NOT ALLOW THE STARTER TO HANG BY ANY CABLES! IT WILL BREAK THE TERMINALS ON THE STARTER!

( Installation - To install, reverse the removal procedure. Torque all bolts on the starter relay pins to 53 In/Lbs.

NOTE: When the battery is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn PCM strategies.

Q(

Make sure the ___________________________ installed over the starter terminal and is reinstalled after servicing.

What will happen if the starter is allowed to “hang” by it cables during service? _____________________________

When the battery is disconnected and reconnected, some abnormal _____________________________ may occur

while the vehicle relearns its adaptive strategy. The vehicle may need to be driven ________________________ or more to relearn PCM strategies.

(Instructor’s Signature _________________________________________________________________

( SECTION 3 On Car Starter Motor Inspection – Customer Complaint – “No Crank”

(If a starter does not run, and the battery checks out, this simple test may be preformed on any vehicle. The test is broken down to inspect the most basic parts of a starter circuit. Proper power and ground must be in the right place at the right time in order for the starter to function when the driver needs it. A “No Crank” is very different from a “No Start”. A No Crank means that the starter is NOT functioning and it or the battery may be at fault. A No Start means the vehicle cranks, but will not run. This could be a base engine problem, fuel delivery or ignition system failure. Before performing this test the battery must be fully inspected and checked!

WARNING: When servicing the starter motor or working underhood in the vicinity of the starter motor, note the heavy gauge input lead connected to the starter solenoid is hot at all times. Make sure the protective cap is installed over the terminal and is reinstalled after servicing.

Tools you will need:

2001 Ford Windstar

Tool Board

Fused Jumper Wire

DVOM

1 - CHECK THE BATTERY GROUND CABLE

( Measure the voltage between the positive battery post and the battery ground cable connection on the engine. KEEP THE IGNITION OFF!

( Is the voltage greater than 10 volts?

Yes – Go on to step 2 –

(This means the battery ground cable is functioning.

No - INSTALL a new battery ground cable. TEST the system for normal operation.

Test Results: ______________________________________

2 - CHECK THE STARTER MOTOR GROUND

( Measure the voltage between the battery positive post and the starter motor case.

( Is the voltage greater than 10 volts?

Yes - Go on to step 3 –

(This means the starter motor has a good ground. This same test could have been done with a DVOM and measuring OHMS from the (-) battery terminal to the ground case of the starter.

No - CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.

Test Results: ______________________________________

3 - CHECK THE POWER SUPPLY TO THE STARTER MOTOR

( Measure the voltage between starter motor B-pin and ground.

( Is the voltage greater than 10 volts?

Yes - Go on to step 4 –

(This means the starter motor has a good power. This same test could have been done with a DVOM and measuring OHMS from the (+) battery terminal to the B-pin of the starter.

No - INSTALL a new positive battery cable. TEST the system for normal operation.

Test Results: ______________________________________

4 - CHECK THE STARTER MOTOR B-PIN

( Connect a fused (30A) jumper wire to the B-pin of the starter motor. Momentarily connect the other lead of the jumper wire to the starter motor S-pin.

( Did the starter motor engage and the engine crank?

Yes - Go on to step 5 –

(This means the starter motor has a good power and ground. This test “bypasses” the clutch interlock, or neutral safety switch. If the vehicle ignition is in the ON position – the vehicle will start! Even if the vehicle is in gear or drive!

No - INSTALL a new starter motor. TEST the system for normal operation.

Test Results: ______________________________________

5 - CHECK THE START INPUT TO THE STARTER MOTOR

( Disconnect Starter Motor S-Pin

( Measure the voltage between starter motor S-Wire (YE/LB), harness side and ground, while placing the ignition switch in the START position.

( Is the voltage greater than 10 volts?

Yes - (This means the starter motor has a start signal from the ignition switch. Remember that the ignition switch starter signal must pass through either the clutch interlock or neutral safety switch.

No - Check Ignition switch and Transmission Range Switch (Neutral Safety)

Test Results: ______________________________________

The Reason for the No-Crank is:

____________________________________________________________________________________________

(Instructor’s Signature _________________________________________________________________

(Things to remember from this lab:

High Resistance Can Cause a Slow or no Crank Situation in a starter circuit

An internal short in the starter windings can cause a Slow or no Crank Situation in a starter circuit

There must be a good connection to all starter circuit components (B, M, and S)

Starter bolts, and wires must be torqued to prevent poor connections

The S wire must have power to the starter relay or solenoid in the START position.

NATEF TASKS - VI. ELECTRICAL/ELECTRONIC SYSTEMS

C3. Inspect and test starter relays and solenoids; determine necessary action. P-2

C4. Remove and install starter in a vehicle. P-1

C5. Inspect and test switches, connectors, and wires of starter control circuits; perform necessary action. P-2

C6. Differentiate between electrical and engine mechanical problems that cause a slow-crank or no-crank condition. P-2

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(+) (-)

M

IGN SW

SAFETY

RELAY

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