Alternator - Models W/integral Regulator Ford Econoline E350

DESCRIPTION

Note. Unless otherwise specified, references to Pickup include the F350 Super Duty commercial chassis.

Major components of the Motorcraft Integral Alternator-Regulator (IAR) system with external fan are end frames, rotor, stator, rectifier assembly and electronic voltage regulator mounted on the rear of the alternator. (Scheme 6)

Scheme 6

BELT TENSION

Check condition and tension of alternator drive belt prior to performing any on-vehicle charging system tests. Replace belt and/or repair tensioner mechanism if necessary. On vehicles with automatic belt tensioner, belt tension is okay if belt length indicator is within limit marks on tensioner. On vehicles without automatic belt tensioner, adjust alternator drive belt to specification. See ALTERNATOR BELT ADJUSTMENT SPECIFICATIONS table.

ALTERNATOR BELT ADJUSTMENT SPECIFICATIONS

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

Scheme 7

Scheme 8

1. Check condition of fuse link, battery terminals, battery cables, connections and belt tension. Make any required corrections. Ensure battery is in good condition and is fully charged. Go to next step.
2. Connect voltmeter to battery posts. Record voltmeter indication as base voltage. Start and run engine at 1500 RPM with no electrical load. Read voltmeter when voltage stabilizes. If there is no voltage increase, or if voltage increases to less than.5 volt greater than base voltage, go to step 4). If voltage increase is no greater than 2.0 volts, go to step 3). If voltage increase is greater than 2.0 volts, go to step 10).
3. Load alternator by switching heater/air conditioner blower motor to high speed and headlights to high beam. Increase engine speed to 2000 RPM. Voltmeter should indicate at least.5 volt higher than base voltage. If voltage increase is within specification, alternator operation is normal. If voltage increases to less than.5 volt higher than base voltage, go to step 4).
4. Unplug connector from voltage regulator. Measure resistance between regulator "A" and "F" terminals. If resistance is greater than 2.4 ohms, go to step 5). If resistance is not greater than 2.4 ohms, replace voltage regulator.
5. Connect wiring to regulator. Connect voltmeter negative lead to rear alternator housing. Connect voltmeter positive lead to terminal "A" screw of regulator. (Scheme 7) Meter should indicate battery voltage. If battery voltage is not present, service "A" circuit wiring.
6. With ignition off, connect voltmeter positive lead to terminal "F" screw of regulator. If battery voltage is present, go to step 7). If battery voltage is not present, repair or replace alternator.
7. Set ignition switch to ON position (engine not running). If meter indicates more than 1.5 volts, go to step 8). If meter indicates less than 1.5 volts, go to step 9).
8. Unplug alternator wiring connector. Connect 12-gauge jumper wires between alternator "B+" terminals and mating connector terminals. (Scheme 8) Connect voltmeter positive lead to "B+" terminal on alternator. Repeat step 3). If voltage increases to greater than.5 volt more than base voltage, repair wiring harness from alternator to starter relay. If increase is less than.5 volt, go to step 9).
9. Connect jumper wire from rear alternator housing to terminal "F" screw of regulator. Repeat step 3). If voltage increase is greater than 0.5 volt more than base voltage, replace regulator. If voltage increase is not greater than.5 volt more than base voltage, repair or replace alternator.
10. With engine off and ignition on, measure voltage at voltage regulator terminal "F" and at starter relay. If difference between readings is.5 volt or less, go to step 11). If difference between readings is greater than.5 volt, repair "A" circuit wiring.
11. Check for loose voltage regulator ground screws, poor engine ground, or poor alternator ground. Repair as necessary. If screws are okay, go to next step.
12. With ignition off, measure voltage at voltage regulator "A" and "F" terminals. If battery voltage does not exist at each terminal, repair or replace alternator. If battery voltage exists at each terminal, replace voltage regulator.

STATOR GROUND TEST

1. Remove stator from alternator. Set ohmmeter to X1000 scale. Connect one ohmmeter probe to any stator lead. Connect other probe to stator core. Ohmmeter indication should be infinity.
2. If meter needle moves, stator winding is shorted to core and must be replaced. Repeat test for each stator lead. DO NOT touch probes or stator leads, as an incorrect reading will result.

STATOR CONTINUITY TEST

Disconnect stator from rectifier assembly. Set ohmmeter to X1 range. Connect one ohmmeter probe to any stator lead. Connect other ohmmeter probe to another stator lead. If continuity does not exist, stator is open, and should be replaced. Repeat test for each pair of stator leads.

ROTOR TEST

1. Remove rotor from alternator. Set ohmmeter to X1 scale. Measure resistance between rotor slip ring. Resistance should be 2.0-3.9 ohms. Replace rotor if resistance is not within specification.
2. Set ohmmeter to X1000 scale. Connect one ohmmeter probe to either slip ring. Connect other probe to rotor shaft. Resistance other than infinity indicates rotor is shorted to shaft and must be replaced. Damaged slip ring terminals or solder touching rotor shaft can cause shorted condition.

Note. Digital ohmmeter CANNOT be used for following test. Resistance measurements may differ slightly from specification, depending on ohmmeter used.

DIODE TEST

1. Remove rectifier assembly from alternator. Set ohmmeter to X1 scale. Connect one ohmmeter probe to either terminal screw. Connect other probe to each diode lead terminal in turn. Record resistance measurements.
2. Transpose probes and repeat test. All diodes should have low resistance (6-10 ohms) in one direction and show no needle movement with ohmmeter probes transposed. Repeat test for other set of diodes, moving first probe to other terminal screw. If measurements are not as specified, replace rectifier assembly.

REMOVAL & INSTALLATION

Disconnect battery negative cable. Disconnect wiring from alternator. Disengage drive belt from alternator pulley. Remove attachment bolts and alternator. Reverse removal procedure to install.

NOTES & CAUTIONS

1. Use only high-temperature bearings when rebuilding alternator. Standard bearings will result in alternator failure.
2. Clean rectifier base plate using a clean cloth. Apply a 3/32" ( 2.0 mm) wide by 3/4" (20 mm) long strip of Heat Sink Compound (ESF-M99G138-A) lengthwise across rectifier base plate.
3. Place a small amount of waterproof sealant over brush pin hole. DO NOT use silicone sealant. Rotate pulley to check for freedom of movement.
4. For exploded view of alternator (Scheme 9)

Scheme 9

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• COMPUTER RELEARN PROCEDURES