Alternator, good or bad?
#1
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Alternator, good or bad?
This is on my '87 Formula which I recently acquired. It has some electronic gremlins I'm trying to work through.
Okay, the alternator.
12.5 V on battery, 12.5 V when car is started, 11-ish when under load , (lights, fan, radio). All connection look good. Seems like the alternator is bad. But before replacing or rebuilding I take it to the parts store for testing and it passed.
So either the parts store testing isn't picking something up like a bad regulator or something? Or my problem is not with the alternator.
Any thoughts? I'm out of ideas.
Okay, the alternator.
12.5 V on battery, 12.5 V when car is started, 11-ish when under load , (lights, fan, radio). All connection look good. Seems like the alternator is bad. But before replacing or rebuilding I take it to the parts store for testing and it passed.
So either the parts store testing isn't picking something up like a bad regulator or something? Or my problem is not with the alternator.
Any thoughts? I'm out of ideas.
#2
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: Alternator, good or bad?
Post an Image of the Alternator showing the Electrical Connector...
Lets see what the Wires from the Connector are connected to, because it seems that the Alternator is not "Exciting"...
The Voltage Regulator Circuit may not have the correct connection.
Lets see what the Wires from the Connector are connected to, because it seems that the Alternator is not "Exciting"...
The Voltage Regulator Circuit may not have the correct connection.
#6
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: Alternator, good or bad?
In the First Image there was the Connector Port for the Wiring related to the Voltage Regulator.
Can you Post an Image where I can see the Connector on the Alternator.
I want to see if the wires for the Voltage Regulator are present.
The Connector should look like this:
Then try and see what they are connected to...
Can you Post an Image where I can see the Connector on the Alternator.
I want to see if the wires for the Voltage Regulator are present.
The Connector should look like this:
Then try and see what they are connected to...
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#10
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Re: Alternator, good or bad?
I think this is related to your Choke Light issues:
I think the above is for 1985 as it matches my 1985 manual, but we know there are some differences with your 1987. However, if you're missing the circuit between the ignition switch and alternator then it will not excite at idle and the choke light will not operate correctly. This would be why the alternator is not charging in your car but passes the test at your parts store.
I think the above is for 1985 as it matches my 1985 manual, but we know there are some differences with your 1987. However, if you're missing the circuit between the ignition switch and alternator then it will not excite at idle and the choke light will not operate correctly. This would be why the alternator is not charging in your car but passes the test at your parts store.
This is on my '87 Formula which I recently acquired. It has some electronic gremlins I'm trying to work through.
Okay, the alternator.
12.5 V on battery, 12.5 V when car is started, 11-ish when under load , (lights, fan, radio). All connection look good. Seems like the alternator is bad. But before replacing or rebuilding I take it to the parts store for testing and it passed.
So either the parts store testing isn't picking something up like a bad regulator or something? Or my problem is not with the alternator.
Any thoughts? I'm out of ideas.
Okay, the alternator.
12.5 V on battery, 12.5 V when car is started, 11-ish when under load , (lights, fan, radio). All connection look good. Seems like the alternator is bad. But before replacing or rebuilding I take it to the parts store for testing and it passed.
So either the parts store testing isn't picking something up like a bad regulator or something? Or my problem is not with the alternator.
Any thoughts? I'm out of ideas.
#11
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
I think this is related to your Choke Light issues:
I think the above is for 1985 as it matches my 1985 manual, but we know there are some differences with your 1987. However, if you're missing the circuit between the ignition switch and alternator then it will not excite at idle and the choke light will not operate correctly. This would be why the alternator is not charging in your car but passes the test at your parts store.
I think the above is for 1985 as it matches my 1985 manual, but we know there are some differences with your 1987. However, if you're missing the circuit between the ignition switch and alternator then it will not excite at idle and the choke light will not operate correctly. This would be why the alternator is not charging in your car but passes the test at your parts store.
#12
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Re: Alternator, good or bad?
It depends. The digital cluster used a hidden bulb that acted as a resistor. In the analog setup, like yours, I believe it's just a resistor wire.
The alternator not charging could be why your Choke Light is on while running. This is also why I asked about that previous post where you said you needed a jump while out driving, as that would not be normal if the alternator was charging and you didn't shut off the vehicle. The alternator needs to put out voltage to kick the choke heater relay off (electrically) and turn off the choke light. These issues are most likely related but finding out exactly the fault is difficult, especially without the proper 1987 manual or diagram. There's a lot more knowledgeable people that probably have the answer.
The alternator not charging could be why your Choke Light is on while running. This is also why I asked about that previous post where you said you needed a jump while out driving, as that would not be normal if the alternator was charging and you didn't shut off the vehicle. The alternator needs to put out voltage to kick the choke heater relay off (electrically) and turn off the choke light. These issues are most likely related but finding out exactly the fault is difficult, especially without the proper 1987 manual or diagram. There's a lot more knowledgeable people that probably have the answer.
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#14
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Car: 1989 IROC-Z. Original owner
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Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
Put a new alternator on. I felt it was sketchy. Failed at one auto parts store passed at another.
#15
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Car: 1989 IROC-Z. Original owner
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Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
#16
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Car: 1989 IROC-Z. Original owner
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Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
#17
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: Alternator, good or bad?
I offer the OEM Exciter Resistor in a Jumper Harness for Different GM Alternators:
As well as a Version with a easily replaceable socketed ATM Style Resistor:
I offer these for all different GM Alternators (as well as adapters), look for your Connector Style below:
#18
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
For the Swap Guys and guys without Original Connections/ Wiring...
I offer the OEM Exciter Resistor in a Jumper Harness for Different GM Alternators:
As well as a Version with a easily replaceable socketed ATM Style Resistor:
I offer these for all different GM Alternators (as well as adapters), look for your Connector Style below:
I offer the OEM Exciter Resistor in a Jumper Harness for Different GM Alternators:
As well as a Version with a easily replaceable socketed ATM Style Resistor:
I offer these for all different GM Alternators (as well as adapters), look for your Connector Style below:
#19
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Alternator, good or bad?
Just so I am 110%, I switched batteries with another car and no difference.
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