free website stats program Power Commander Explained (PC III) | Harley Davidson Forums

Power Commander Explained (PC III)


BOT Machine
Think of the Power Commander as a digital tuning device like having a handful of jets and tunable ignition. It allows you to fine tune the EFI.

Since we are dealing with an open loop EFI the computer has no idea what is going on with the motorcycle exhaust so it cannot compensate for lean or rich conditions. The EFI is much like a 1985 Chevy throttle body in it's technology. The Power Commander (PC) allows you to alter the timing (PCIII-PCIIIR) and the fuel mixture as needed to tune your particular combination. There are programs called "maps" that can be downloaded into the PC. There are many maps and more being developed constantly. These maps are developed from motorcycles running specific combinations of parts. For example, a Screaming Eagle air cleaner motorcycle part, mufflers and stage I ECM upgrade. These maps are usually all that is needed to get the EFI running spot on. Fine tuning, changes to the maps can be done via a connection to a PC/Lap top and the Power Commander software.

If you desire a map specific to your setup or, there is no map for your setup you can have the motorcycle tuned on a Dyno-Jet Dynamometer. This will allow the operator to fine tune your air- fuel mixture and timing-advance curves

Powercommander is working on a program that we will most likely be able to download, from their website, that will move the rev limiter to you won't have to pay for the harley one. He said it will be on when it is finished.
thanks Mr. Data, And thanks to Bud White for helping me change the map values on my PC III. I have one question: why does the power commander III map M805-212 for my V&H big shot longs and Arlen ness big sucker air filter only show one table of maps, table 1. the Dyno jet tune shows two sets of maps table one (ft cyl) and table 2 (rr cyl)??
Hi Mr. Data,

You seem to have a lot of knowledge. Maybe you can help me? I am also looking at map M818-044 with Rinehart True Duals Ness Big Sucker, stock ECM, Rev Xtend.

I have an 08 Streetglide with an Ness Big Sucker Air filter kit, Vance and Hines True Dual Headers, and Thundercone (Thunderheader) Slip-ons. I also have Panacea LED tail lights.

I recently purchased a PCIIIUSB and selected map M818-026 for "2008 HD Touring Model *Adv. Map* True Dual headers, thundercone slip-ons, Screamin' Eagle air filter, Stock ECM, Rev Xtend enabled." I installed the map properly, however here's my problem:

When on the throttle in 1st at 4000 RPM, 2nd at 4,250 RPM, or 3rd gear at 4,250 RPM (it probably happens in 4th, 5th, and 6th too, haven't gone that fast) the bike stutters, loses power, Tachometer drops, and then it backfires and starts up again.

Any ideas? says it has an issue with custom led lights for map 109-411. (See quote below)

Applicable to 109-411
Symptom: The bike randomly cuts out or sputters while riding.

If custom LED tail lights are being used, they may give off interference up the line that causes the Power Commander to loose its 12 volt reference for power and shut off. The power wire (Red wire with bullet connector terminals) will need to be relocated to a keyed, solid 12 volt power source.
Do you think that this my problem even though the bike is different?

What is the fuel firmware for HD for PCIII USB?

Would love any feedback.