2 pin 2006 + alternator. Don't throw it away!!
#181
Given the PowerTap connector and the INPUT/OUTPUT connector are at the same point on the wiring loom, I assume I can wire one of the output wires to a wire connected to the 5V output, with the 1K ohm resistor, and then just run a single wire to the alternator. Given I have the ECU in the cabin, this connection will all be under the dash. The result in the engine bay should be nice and neat.
#182
This is interesting, found it when searching around about the wiring harness. Looks like an elegant solution - I assume it has a pullup resistor already in the harness. I think this must be a new product?
https://www.holley.com/products/fuel.../parts/558-475
https://documents.supershops.com/558...structions.pdf
https://www.holley.com/products/fuel.../parts/558-475
GM PWM ALTERNATOR HARNESS
For use with 2007+ PWM GM Alternatorshttps://documents.supershops.com/558...structions.pdf
#183
TECH Fanatic
Thread Starter
This is interesting, found it when searching around about the wiring harness. Looks like an elegant solution - I assume it has a pullup resistor already in the harness. I think this must be a new product?
https://www.holley.com/products/fuel.../parts/558-475
https://documents.supershops.com/558...structions.pdf
https://www.holley.com/products/fuel.../parts/558-475
GM PWM ALTERNATOR HARNESS
For use with 2007+ PWM GM Alternatorshttps://documents.supershops.com/558...structions.pdf
#184
This is interesting, found it when searching around about the wiring harness. Looks like an elegant solution - I assume it has a pullup resistor already in the harness. I think this must be a new product?
https://www.holley.com/products/fuel.../parts/558-475
https://documents.supershops.com/558...structions.pdf
https://www.holley.com/products/fuel.../parts/558-475
GM PWM ALTERNATOR HARNESS
For use with 2007+ PWM GM Alternatorshttps://documents.supershops.com/558...structions.pdf
Documentation is dated March 2022.
#185
TECH Senior Member
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For people that are using Holley EFI, I just ran across this:
https://www.holley.com/products/fuel.../parts/558-475
It is a sub-harness for the 2-Pin alternators. The instructions have some good info.
Andrew
https://www.holley.com/products/fuel.../parts/558-475
It is a sub-harness for the 2-Pin alternators. The instructions have some good info.
Andrew
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cynick (09-03-2022)
#186
At the risk of asking a dumb question...
The resistor will obviously generate heat. Is it OK to wrap in electrical tape or braid sleeving? I'm assuming Holley use a resistor in their product, and they use braid sleeving.
Thanks
The resistor will obviously generate heat. Is it OK to wrap in electrical tape or braid sleeving? I'm assuming Holley use a resistor in their product, and they use braid sleeving.
Thanks
#188
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Thread Starter
#189
@LSswap thank you for coming up with all this and taking the time to document it and help others! It's greatly appreciated! I created an account here because this thread showed up on Google as I was researching how to control the alt.
I do have a question though. So when we run the L wire to power the controller then out of the controller to the L pin. We also disconnect the F wire so it doesn't report back to the ECU, correct?
My question is does the ECU throw a code because it no longer sees the alternator?
If it helps, this is on a 2016 6.0L out of a 2500hd with E78 ecm. The factory alt is a Denso 2 wire.
I do have a question though. So when we run the L wire to power the controller then out of the controller to the L pin. We also disconnect the F wire so it doesn't report back to the ECU, correct?
My question is does the ECU throw a code because it no longer sees the alternator?
If it helps, this is on a 2016 6.0L out of a 2500hd with E78 ecm. The factory alt is a Denso 2 wire.
#190
TECH Fanatic
Thread Starter
@LSswap thank you for coming up with all this and taking the time to document it and help others! It's greatly appreciated! I created an account here because this thread showed up on Google as I was researching how to control the alt.
I do have a question though. So when we run the L wire to power the controller then out of the controller to the L pin. We also disconnect the F wire so it doesn't report back to the ECU, correct?
My question is does the ECU throw a code because it no longer sees the alternator?
If it helps, this is on a 2016 6.0L out of a 2500hd with E78 ecm. The factory alt is a Denso 2 wire.
I do have a question though. So when we run the L wire to power the controller then out of the controller to the L pin. We also disconnect the F wire so it doesn't report back to the ECU, correct?
My question is does the ECU throw a code because it no longer sees the alternator?
If it helps, this is on a 2016 6.0L out of a 2500hd with E78 ecm. The factory alt is a Denso 2 wire.
I definitely would disconnect the L wire from the ECU so the PWM generator and ECU don't fight each other.
Just curious, since your ECM is probably PWM capable, why are you trying to bypass this?
#191
Good question. I don't know since I've never had a GM BCM or ECU attached to it. Hypothetically only, if you leave the "F" wire connected and the ECU sees that the alternator can't keep up, maybe it will still raise idle rpm. Just a guess.
I definitely would disconnect the L wire from the ECU so the PWM generator and ECU don't fight each other.
Just curious, since your ECM is probably PWM capable, why are you trying to bypass this?
I definitely would disconnect the L wire from the ECU so the PWM generator and ECU don't fight each other.
Just curious, since your ECM is probably PWM capable, why are you trying to bypass this?
So my understanding is I was going to use the 5v ECU wire that's originally the L wire as my power wire for the new controller. Then the controllers pwm output goes to the L pin. So in this way that ECU wire is still there but it's sending signal to the controller instead of the alt.
I suppose disconnecting the F wire from the alternator might be best because then the ECU will just send a constant duty cycle to the controller input, which may be better for the controller as opposed to receiving a 5v with a fluctuating duty cycle.
#192
TECH Fanatic
Thread Starter
So my understanding is I was going to use the 5v ECU wire that's originally the L wire as my power wire for the new controller. Then the controllers pwm output goes to the L pin. So in this way that ECU wire is still there but it's sending signal to the controller instead of the alt..
Some of the PWM modules mentioned earlier can be powered by 12V, but I'm not a fan of that because if you don't set them right before you connect to the alternator, you might accidentally fry the alternator's intelligent regulator by giving it 12V.
GM had a reason to make the voltage fluctuate. They have a charging methodology that maintains the batteries health better than just a steady voltage. Maybe put a toggle switch that will toggle the "L" wire between the ECU and the PWM module since you have a PWM capable ECU. To be honest I started this thread for people who didn't have a PWM capable ECU.
#193
GM had a reason to make the voltage fluctuate. They have a charging methodology that maintains the batteries health better than just a steady voltage. Maybe put a toggle switch that will toggle the "L" wire between the ECU and the PWM module since you have a PWM capable ECU. To be honest I started this thread for people who didn't have a PWM capable ECU.
Basically I don't think pwm alternators are better from an electrical perspective....I think they are just a compromise to show on paper that they are working towards making things as fuel efficient as possible. If you need a heavy on demand power, they are terrible.
Now in factory vehicles where the ECU is controlling pwm fans and a pwm alt, and seeing every other load in the entire vehicle, it may work decent because the ecm knows it needs to ramp up the alternator output and fans together, etc. I'm sure the ecm has tables for all that. But my e78 ecm doesn't have fan control (HD trucks originally had clutch fans) so my fan system is separate from ecm and it takes a while of the voltage being low before the ecm starts bringing it back up. Also it's swapped into a vintage 62 step van so I don't have the body control modules or any of that, just the engine and ecm.
A lot of guys that have big stereo systems with pwm alt's are also starting to do this to maintain a solid voltage output.
#194
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#195
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This is awesome. I have a turbo f body with cbr relocation alternator and have battled voltage issues for years with ls1 style alternators. The 05-06 truck alternator does not fit but the l86 alternator does and is rated at 170 amp. I have 2 fuel pumps and dual derale pushers. Bought the box and controls the l86 alternator perfectly. With all lights, pumps and fans on it holds 14.5 volts.
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Paul Bell (01-23-2023)
#196
That's MISTER MODERATOR
iTrader: (9)
This is awesome. I have a turbo f body with cbr relocation alternator and have battled voltage issues for years with ls1 style alternators. The 05-06 truck alternator does not fit but the l86 alternator does and is rated at 170 amp. I have 2 fuel pumps and dual derale pushers. Bought the box and controls the l86 alternator perfectly. With all lights, pumps and fans on it holds 14.5 volts.
#199
I don't think so. The 2006+ alternator has it's own table probably somewhat similar to the one you posted internally. It does what you're trying to do on it's own. All you need to do is tell it what voltage you want (and give it enough RPM) and it does all this compensation for you.
I would think that your table should not have battery volts in it at all. I predict that if you do, the car's voltage will be unstable since both the Holley and the alternator are going to try to regulate the voltage and constantly fight each other. Instead, the table might be RPM only. Anything under 400 RPM, you'd want to alternator to not load the engine down and anything over 400 RPM you command the alternator to put out the desired voltage..
Remember that for Holley PWM+ and PWM- duty required is opposite.
So let's say you want 14.37 volts above 400 RPM and you are using the PWM- .........Then try 85% across the board under 400 RPM and 30% across the board over 400 RPM and this wiring:
For PWM- these are the command percentages. Find your desired voltage and set that percent over 400 RPM
90% = 11.0 V
80% = 11.56 V
70% = 12.12 V
60% = 12.68 V
50% = 13.25 V
40% = 13.81 V
30% = 14.37 V
20% = 14.94 V
10% = 15.5 V
Let's say you're going to the track and want higher voltage so your ignition and fuel pump have some extra juice. Then you might have a table RPM on one axis and some switch input on the other so you could flip the switch on your dash and command the alternator to put out the higher track voltage.
Once again, I don't have a Holley, so I can't test this.
I would think that your table should not have battery volts in it at all. I predict that if you do, the car's voltage will be unstable since both the Holley and the alternator are going to try to regulate the voltage and constantly fight each other. Instead, the table might be RPM only. Anything under 400 RPM, you'd want to alternator to not load the engine down and anything over 400 RPM you command the alternator to put out the desired voltage..
Remember that for Holley PWM+ and PWM- duty required is opposite.
So let's say you want 14.37 volts above 400 RPM and you are using the PWM- .........Then try 85% across the board under 400 RPM and 30% across the board over 400 RPM and this wiring:
For PWM- these are the command percentages. Find your desired voltage and set that percent over 400 RPM
90% = 11.0 V
80% = 11.56 V
70% = 12.12 V
60% = 12.68 V
50% = 13.25 V
40% = 13.81 V
30% = 14.37 V
20% = 14.94 V
10% = 15.5 V
Let's say you're going to the track and want higher voltage so your ignition and fuel pump have some extra juice. Then you might have a table RPM on one axis and some switch input on the other so you could flip the switch on your dash and command the alternator to put out the higher track voltage.
Once again, I don't have a Holley, so I can't test this.
Just wanted to say that I followed this exactly and it works perfectly. I used my own 1k resistor and a plug that fit the connection just fine.
Used Holleys own instruction sheet for the setup in the software.
@LSswap Thank you so much for this! This is what auto forums are all about and kinda miss them because of it...lol
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G Atsma (03-22-2023)
#200
06 impala
Hello. I purchased the one from brand x. But it never worked. Then I purchased one from Amazon. Well it works for a little bit. Then I did my big 3 upgrade and it stopped working. Removed my big 3 and still doesn’t work. I know it says to use a 5v source but I can’t find one in my car. So I used my remote wire from my head it to turn it on and off. What could I use to get a 5v turn on? Thanks