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Terminator X outputs are G or PWM- only. I wouldn't use the TPS wire for anything. There is a 5v reference wire in the PowerTap. It's the orange wire.
Thanks Andrew.
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.
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?
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?
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?
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
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 resister will get warm, but it will not get so hot as to melt anything.
The resister will get warm, but it will not get so hot as to melt anything.
Andrew
Resistor shouldn't get warm. 1k ohm at 5V = 5 ma. 5ma x 5V = 25 mw. It's like pissing in the ocean, you won't raise the temperature much. Cover it any way you want.
@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.
@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.
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?
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?
Mainly want to use a controller because I don't like the voltage fluctuating and the delay of the alternator having to decide to ramp up. I have added electric fans and don't like them kicking on when they system is at like 13v. The factory fluctuates between 12-15v and I just want to set it up to operate at 14.7 and if the fans kicking on dip the voltage a bit I'd rather it dip into the 13's instead of the 11's or 12s.....also the fans will consume less amperage if the voltage is up.
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.
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..
No. Use the 5V from the ECU that is supplied to sensors or a dedicated 5V supply to supply the PWM module. It needs a constant 5V in.
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.
Originally Posted by SPOautos
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.
My gut feel is that you are less likely to get error codes with the "F" wire still attached to the ECU.
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.
No. Use the 5V from the ECU that is supplied to sensors or a dedicated 5V supply to supply the PWM module. It needs a constant 5V in.
Well I was wondering about that since the 5v had a fluctuating duty cycle, but I just figured it must be fine. Now, In pretty sure that if the F wire is disconnected the L wire probably goes constant because it keeps voltage solid at 13.7. But if you think it's probably better to keep the F wire in tact then I'll look around for another 5v wire. I'm not sure what all is 5v on this engine....usually things like cam and crank sensors are but I don't want to tap into one of those.
Originally Posted by LSswap
My gut feel is that you are less likely to get error codes with the "F" wire still attached to the ECU.
That's probably correct, I guess I just need to hook it all up to a meter or scope and test out a few scenarios to see what triggers cel and to see if disconnecting the F pin causes the L to go constant or not. I really don't mind a cel except for the fact that if a second code is triggered one day, I wouldn't know.
Originally Posted by LSswap
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.
Well I'm of the opinion they just sugar coat it saying it helps the batteries, I think it's really more about the epa pushing them into saving .1 mpg by using the alt less. The factory pwn caused voltage to go from just straight battery voltage where the alt is doing nothing, all the way to 15v and it's reaction to load is somewhat slow. So when I flip on my dual fans that together pull 50-60amps, it kills the voltage until the alternator slowly starts creeping it back up to a decent rate. I'd rather sacrifice .1mpg and have the alt working the way they used too where they always work to maintain a fixed voltage.
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.
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.
If I was a stereo guy (I'm not), let's say the amp is in the back and the voltage drops at the amp are too much. First I'd get a newer hairpin alternator. They are 6 phase and have lower ripple voltage. Then I'd connect a sense wire to an arduino nano to measure the voltage at the amp and tell the alternator to put out a voltage that will result in the voltage desired at the amp. I don't know if the PWM alternator can respond that fast, but it would be an interesting test. The Arduino nano wiring and software are ridiculously easy, all you need is the nano and two resistors.
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.
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.
laytoncamaroz28, for all of us interested in this cool looking mod, can you please post exactly what's needed to do this and how to wire it up?
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.
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
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
06-09-2022, 12:35 AM
