Hi guys - fresh off my success in getting my 2002 Road King going, these things fell out of the right side cover when I took it off; my big questions are (1) where does that big cable with the box on the end go/clip into, and (2), the Power Commander - what does it do? I assume it does something with/about the engine performance, but I've never run one on any of my other bikes - how does it work? Being stashed in the side cover like that I don't guess it's an 'active' component - but how do you read it/what does it do?

 

The Power Commander is basically what has been referred to as a "Piggyback" system that interprets the signal from the O2 sensors then lies to the ECM to produce the Air / Fuel Ratio (AFR) specified in the Power Commander tune.

The Power Vision on the other hand actually flashes the tune straight into the ECM.

Once upon a time, long ago, "Piggyback" tuners were the only work around available to circumvent the EPA mandated AFRs.

When the MoCo changed the architecture of the ECM on the new Center Cooled bikes, Dyno Jet had
difficulty developing a new tuner to flash the ECM and offered a new version the Power Commander as an interim solution.

Recently, Dyno Jet has produced an updated version of the Power Vision that is compatible the new center cooled bikes.

This explanation is offered as my opinion only.

I am certain Lucas or Jaime from Fuel Moto can explain it better.

I can't speak highly enough about the Technical Support and Customer Service at Fuel Moto!

 

That is a old tuner it doesn't even have USB. It probably has some type of tune in it for that bikes changes(mufflers, air cleaner and or cams). As long as it runs good and you don't plan to change it , should be fine. I would buy some liquid tape and seal up the wires, then zip tie everything up.

Can also make broad changes with the buttons on it low mid and high. The lights bar on the side will show the change.

 

The PowerCommander is plugged 'in line' between the OEM Harness and the ECM/ECU. If you were to ever want to remove it (I'm not suggesting you do that), you'd simply plug the OEM side of the Wiring harness back into your ECM/ECU and it would revert back to the Factory Tune.
They were a decent option (back in the day) for basic fuel & ignition tuning when upgrading exhaust and/or doing intake modifications.

As others have mentioned, it's a 'piggyback' sort of tuner.

 

You've gotten all sorts of good advice here, so I won't reiterate any (well, too much, anyway).
Just from looking at it, I can't tell if it's a PCll or PClll, but if your bike's an '02, it's probably a PC lll. You could use it to regulate fuel and spark, and Dynojet had a bunch of maps on its site which you could select according to whatever mods you had. You connected to the PC with your laptop. It was kind of fun and worked well enough.
My advice would be if your bike is running well, leave it alone, as I don't believe Dynojet supports that model any longer. And don't touch those buttons. If your bike is not running well, still leave it alone and get another tuner.

 

While I'm not a fan of the piggyback tuners in general, this one is OLD.... and they are known to eventually fail.

IMHO....Any symptoms that this PCIII isn't functioning properly, I would suggest a new tuner is in order rather than trying to fix/adjust this one, then disconnect the PCIII, and throw it in the trash.

 

The unit has a sticker that reads "Power Commandeer 3"
It connects between the original wire harness and the computer on bike.
It can be removed or remain in place.
If you remove the unit then you will need to address additional fuel needs if the bike is not factory stock.
Unless the Power commander plastic box gets damaged or the wiring gets damaged or someone fry's the electrical system with a jump start then unit remains reliable.
There were two versions of the Power Commander 3...The older one had a 9 pin computer connector and the newer used a USB connector.
They sell 9 pin to USB connectors that actually work and are rather inexpensive but your home computer needs to be compatible.
It looks to be an earlier 9 pin unit.
Basically you had a CD that was used to download program into a compatible home computer.
There were a hand full of readily available down loads for various fuel addition at different throttle % area's.
You would then connect unit to home computer and add fuel in different cells based on performance needs and air cleaner or exhaust changes for example.
The buttons on the other hand had less adjustment and were used to add something like a maximum of 5% to each of the three trim levels.
They function well for mild builds like free a flow exhaust, free flow air cleaner and a mild CAM.
If it works then consider leaving it alone unless you are showing a massive waste of fuel.
Just protect the box from getting smacked and adding a cover for the cable would be nice too.
Here is a link to research more:
https://www.dynojet.com/downloads/po...iusb-pciiiusb/