alternator problems
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Cross-Country
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alternator problems
hey guys i have a 86 f 150 300 6 standard,,,,my alternator magnatises on the back but it wont charge the battery ,,,,if i take the terminal off it dies straight out,,,what could be the problem,,,and does any one have a charging wiring diagram i could look at,,,thanks guys.
Cargo Master
Joined: Mar 2008
Posts: 2,564
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From: Washington
hey guys i have a 86 f 150 300 6 standard,,,,my alternator magnatises on the back but it wont charge the battery ,,,,if i take the terminal off it dies straight out,,,what could be the problem,,,and does any one have a charging wiring diagram i could look at,,,thanks guys.
Do you have a G2 ALT with 2 push on plugs?
Can you test for voltage with a volt meter?
If not check the fusible link on the starter solenoid.
Did you do anything bad that caused a big spark or arc?
On the technical side, the voltage regulator is energizing the field which is the magnetism you are seeing. The fusible link is the only cheap fix, mostly like need a new ALT.
Jim
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Cross-Country
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yes its a g 2 and its old,,,lol,,,I put a new voltage regulator on but no juice it worked before then stopped then started again now its out,,what else could it be,,,could autozone check it and tell me if its working.
Cargo Master
Joined: Mar 2008
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From: Washington
The power output plug, the one with the 2 large wire has been know to cause problems. (engine fire)
Also does your Voltage regulator (VR) plug have 2 or 3 wires on it? The new VR need 3 wires to work, the old ones where happy with 2 wires
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
More than likely the infamous 2G "Fireplug" has shorted or opened internally.
The alternator is (or was) charging, just either the power is shorted to the case or the power is not making it through the fusible link to the solenoid stud.
The charging pigtail should always be replaced whenever the charging system is worked on (according to the Ford TSB 96214)
Borg-Warner PT-780
Standard Motor Products S-542
Power Plug 4628011
KEM Parts 350-220
Pico 5711
Dorman 85123
Motormite 08622
NAPA VRA400
As for what wire is what...
The rectifier plug has two 10Ga. black/orange wires and a black/white.
These are power out, and stator power for the electric choke respectively.
The regulator plug should have three wires as well:
Yellow/white is the 'sense' wire.
Green/red is the 'key on' exciter current.
White/black is the stator wire.
The alternator is (or was) charging, just either the power is shorted to the case or the power is not making it through the fusible link to the solenoid stud.
The charging pigtail should always be replaced whenever the charging system is worked on (according to the Ford TSB 96214)
Borg-Warner PT-780
Standard Motor Products S-542
Power Plug 4628011
KEM Parts 350-220
Pico 5711
Dorman 85123
Motormite 08622
NAPA VRA400
As for what wire is what...
The rectifier plug has two 10Ga. black/orange wires and a black/white.
These are power out, and stator power for the electric choke respectively.
The regulator plug should have three wires as well:
Yellow/white is the 'sense' wire.
Green/red is the 'key on' exciter current.
White/black is the stator wire.
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pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
You can only test for resistance with an ohmmeter.
You can test for voltage with a volt meter, and you can test for current with a ammeter.
"Power" is measured in watts.
E x I = P
The lt grn/red wire should have battery voltage with the key on.
The yellow/white wire should have voltage equal to alternator output with the engine running.
The white/blk stator wire should have 2/3 AC with the alternator turning.
Do NOT disconnect the alternator while running.
Do NOT try to test for Amps unless you are using an INDUCTIVE ammeter rated for at least 75A
If you suspect the regulator, connect a voltmeter to the hot stud of the solenoid or the battery and see what the output is with the engine running.
Then ground the screw (marked "Ground Here To Test") on the back of the regulator.
Voltage should jump to ~17V and the alternator should load the engine noticeably.
You can test for voltage with a volt meter, and you can test for current with a ammeter.
"Power" is measured in watts.
E x I = P
The lt grn/red wire should have battery voltage with the key on.
The yellow/white wire should have voltage equal to alternator output with the engine running.
The white/blk stator wire should have 2/3 AC with the alternator turning.
Do NOT disconnect the alternator while running.
Do NOT try to test for Amps unless you are using an INDUCTIVE ammeter rated for at least 75A
If you suspect the regulator, connect a voltmeter to the hot stud of the solenoid or the battery and see what the output is with the engine running.
Then ground the screw (marked "Ground Here To Test") on the back of the regulator.
Voltage should jump to ~17V and the alternator should load the engine noticeably.
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