Where/how do you disconnect the 02 sensor?

[Blind Squirrel]

I installed a Power Commander III that has the "Wally smoothness map" loaded in it. I took the bike out for a spin; smooth as glass... until I pulled into my driveway. The bike is running super rich. I did some searching and discovered that you need to disconnect the 02 sensor. Problem is I don't know where to disconnect it at.

HELP!

Thanks.

 

[Reaper]

I installed a Power Commander III that has the "Wally smoothness map" loaded in it. I took the bike out for a spin; smooth as glass... until I pulled into my driveway. The bike is running super rich. I did some searching and discovered that you need to disconnect the 02 sensor. Problem is I don't know where to disconnect it at.
HELP!

Thanks.

Under the gas tank - quick disconect. Just follow the wires up from the sending unit.

 

[Blind Squirrel]

Disregard my last! I used good ol' Google and found it! https://www.fjrtech.com/getdbitem.cfm?item=11

 

[Fred W]

Looks like this when disconnected:

Orange connector to the right of V4 in above picture

 

[FJRay]

When the power comander was installed on mine the O2 sensor wasn't disconnected and it runs great so I never messed with it. It was set up on a dyno so maybe that makes a difference. Been that way for years so I'm not going to change anything at this point.

 

[Fred W]

That doesn't make any sense. As long as the O2 sensor is still hooked up the ECU will attempt to go closed loop and will be constantly fighting with the PCIII. Everything I've ever seen from DynaJet about installing the PCIII says you have to disconnect the O2 sensor.

 

[wfooshee]

The Power Commander III needs to have the O2 sensor disconnected. The ECU will hunt for its own micture and override the Power Commander's adjustments. If the PC-III says "+4 rich" at a certain point of the table, the ECU detects rich via the O2 sensor and leans it out. The PC-III just keeps "+4 rich" as that's all it knows, and the ECU has compensated by leaning itself out. It has no awareness of the PC-III, and the PC-III has no awareness of the O2 feedback.

When the O2 sensor is missing, the ECU runs a default map, and it's that map the PC-III needs to be working against. With the O2 sensor connected the ECU compensates for the PC-III's adjustments and returns to its desired mixtures.

Edit: Tree'd by Fred, but I 'splained it better!

 

[FJRay]

I wouldn't think about disputing what you guys are saying as I have read the same thing. I got the PC almost free at WFO in Wa. because I dealt with the dealer there and they wanted to sell some and Mine was the test mule for their new dyno. I didn't know the O2 wasn't disconnected for some time. I got to tracing the wires one day and found it still hooked up but it runs great and I don't have the stuff to remap it so I just left it alone. After the install it ran much smoother and still gets 50 mpg at reasonable cruise speed. Maybe someday when I am going to be close to home I will pull the plug and see what happens.

 

[user 213]

Makes me wonder if the shop just cut the wires someplace when setting up your PC III Ray. The ECU won't like O2 sensor input. The whole point is to default to the PC III map instead of using sensor data. If sensor data is available, it won't use the map, or will do odd things.

Another possibility is that your sensor is dead. No signal, or an un-changing signal, would cause the ECU to default to the map.

 

[FJRay]

Makes me wonder if the shop just cut the wires someplace when setting up your PC III Ray. The ECU won't like O2 sensor input. The whole point is to default to the PC III map instead of using sensor data. If sensor data is available, it won't use the map, or will do odd things.
Another possibility is that your sensor is dead. No signal, or an un-changing signal, would cause the ECU to default to the map.

I have followed the wires all the way to the coupler by the throttle body and they are intact. The idea of a bad sensor may be the case but it must have been bad before the PC was installed. This has been installed for about 70k. Maybe come next winter I will dig into it but it runs just fine so if it isn't broken I'm not going to fix it.

 

[JamesK]

I guess another possible reason you've not had problems with this wrong setup, is if your PCIII is running a Zero map, thus it's not really doing anything, hence not conflicting with the ECU signals/maps based on the O2 sensor input.

 

[FJRay]

I guess another possible reason you've not had problems with this wrong setup, is if your PCIII is running a Zero map, thus it's not really doing anything, hence not conflicting with the ECU signals/maps based on the O2 sensor input.

I supose thats posible but when it was installed there was a couple hours of dyno time messing around to see what worked best and they gave me a floppy disc with three maps if I wanted to try them. Still have the disc but don't have any way to try the maps. Wrong or not, thats the way it is and it did help a lot on the low end. It runs great and I got 156 out of it at Bonneville so its not to wrong. Not trying to argue with anybody but thats the way mine is set up.

 

[RadioHowie]

I guess another possible reason you've not had problems with this wrong setup, is if your PCIII is running a Zero map, thus it's not really doing anything, hence not conflicting with the ECU signals/maps based on the O2 sensor input.

I supose thats posible but when it was installed there was a couple hours of dyno time messing around to see what worked best and they gave me a floppy disc with three maps if I wanted to try them. Still have the disc but don't have any way to try the maps. Wrong or not, thats the way it is and it did help a lot on the low end. It runs great and I got 156 out of it at Bonneville so its not to wrong. Not trying to argue with anybody but thats the way mine is set up.

Yer ballz is gonna fall off!

 

[FJRay]

I guess another possible reason you've not had problems with this wrong setup, is if your PCIII is running a Zero map, thus it's not really doing anything, hence not conflicting with the ECU signals/maps based on the O2 sensor input.

I supose thats posible but when it was installed there was a couple hours of dyno time messing around to see what worked best and they gave me a floppy disc with three maps if I wanted to try them. Still have the disc but don't have any way to try the maps. Wrong or not, thats the way it is and it did help a lot on the low end. It runs great and I got 156 out of it at Bonneville so its not to wrong. Not trying to argue with anybody but thats the way mine is set up.

Yer ballz is gonna fall off!

To late, already fathered four kids to drive me nuts.

 

[user 213]

if it isn't broken I'm not going to fix it.

Wise words. The shop may have tested the output of the O2 sensor, realized it was FUBAR and just left it plugged in and done the dyno work. Easy, no need to unplug, thus one less avenue for corrosion and it wouldn't interfere with the new PC III.

For now, as you said, it works, so no worries. It's just a curiosity to the rest of us. Hmmm, Ray, you've been a curiosity to us at times too. Maybe it's just a family thing with you and your Feej? :lol:

 

[FJRay]

if it isn't broken I'm not going to fix it.

Wise words. The shop may have tested the output of the O2 sensor, realized it was FUBAR and just left it plugged in and done the dyno work. Easy, no need to unplug, thus one less avenue for corrosion and it wouldn't interfere with the new PC III.

For now, as you said, it works, so no worries. It's just a curiosity to the rest of us. Hmmm, Ray, you've been a curiosity to us at times too. Maybe it's just a family thing with you and your Feej? :lol:

Souuldn't there been some kind of trouble code if it was bad????

Very diplomatic response Eric. Maybe it's the tin foil liner in my helmet. I knew this thread would go to shit.

All we need now is sheep boy.

 

[user 213]

Hey, once Fred posted that most excellent picture, the original problem was solved! There was no reason to keep it on track then.

Code, we don't need no stinkin' code! Have you checked for codes? IIRC, just running a PC III causes a code for the O2 sensor.

 

[FJRay]

Hey, once Fred posted that most excellent picture, the original problem was solved! There was no reason to keep it on track then.
Code, we don't need no stinkin' code! Have you checked for codes? IIRC, just running a PC III causes a code for the O2 sensor.

In the almost 8 years I have owmed this thing I have never used the diagnostic tools.

 

[Fred W]

Nope. Use of a PCIII USB, including disconnecting of the O2 sensor doesn't cause any error codes in the ECU, at least not on my 1st gen. The DIAG errors listing in the manual does show that there is a code for O2 sensor inactive (24), stuck high (31) and stuck low (32) but I've never seen any of these and there is a 00 in my DI:61 (error code history).

What I'm guessing may be happening with Ray's bike is the PCIII is doing its thing whenever the ECU has the Fuel Injection running in open loop mode. It only goes closed loop under some very specific circumstances (which are not clearly defined or well understood). When/if it does go closed loop then you won't have any benefit from the PCIII. But it would still be fully functional the rest of the time.