I found that the O2 sensors on my Heritage have been disabled. The connection they plug into have an insert that resembles a plugin with what appears to be a jumper wire. Is this done when a stage one or SERT has been performed. It runs good and the spark plugs are light tan. So I'm assuming the AFR is correct.

 

Might be worth looking into... to see what has actually been done to your tune. With no O2 sensor feedback, I wouldn't assume all is well... maybe it's acceptable, but I see no advantage to removing the closed loop portions of a tune on a street bike...

There are two kinds of maps in Harley Delphi EFI systems...

The early bikes with no O2 sensors have a completely open loop tune (no O2 sensor feedback w/ no real time adjustments) that is based solely on algorithms designed for the bike's engine/mods.

The bikes with O2 sensors have hybrid maps. Portions of the map are closed loop (with O2 sensor feedback w/real time adjustments), mostly in the cruising areas, and then portions of the map are open loop, mostly the high rpm/high load and low rpm/idle sections of the map...

Just FYI... the HD bikes with the O2 sensors & hybrid maps are that way, because they use narrow band O2 sensors which are only accurate in the areas of the tune that are in the cruising portions. They would need to use wide band O2 sensors to accurately adjust the entire spectrum of the tune map in real time...

I'm not sure there is an advantage to removing the O2 sensor feedback from the process.... In fact, many tuning modules, like the DynoJet Target tune, actually take a hybrid map, add wide band O2 sensors, and then convert the map to an entirely closed loop map. This gives O2 sensor feedback and real time adjustments to the entire tune map... their popularity demonstrates the advantages of having O2 sensor feedback to adjust the tune map for current conditions..

The fact that your bike has a plugin or jumper wire, suggests the O2 sensor portion in the ECM is either being "fooled" or being bypassed... Neither course of action, IMHO, is a good way to go...

There are some tuning aids that plug-in between the O2 sensors and the O2 sensor plug. They change the signal sent to the ECM from the O2 sensors to increase the AFR in the closed loop portions of the tune.. I am not a fan of those, because they do nothing for the open loop portions of the tune (high rpm/high load), where the AFR is most critical...

I would want to find out exactly what has been done, how, and why, that required those plugs be put into the O2 sensor harness.

Whatever was done could be acceptable (well to many people, I'd pass) but I would at least want to know what is going on with my bike's tune......

Please report back if you figure out what your bike has... and how it works.. I'm always willing to learn..

 

I'm trying to find out if thats what they do to the O2 sensors when they do a stage 1 modification.
That way if I install a fuelpak or change exhaust and intake I would know what map to use.

 

No....that is not what 'THEY' do for a stage 1.

 

That eliminates one prospect. Thanks. Would it be if a SERT was on it?

 

The power commander 5 comes with them...called o2 optimizers. They just make the ecm think the afr is right where it should be and all is well. I was told it keeps the ecm from trying to correct the tune that was either flashed or thats being corrected by a piggy back tuner. Does your bike run good? Like my grandfather used to say if it ain't broke...you know the drill. When you're ready to do further upgrades then get a new tuner too and put some o2 sensors in. I removed mine when I first bought a pc5 and when I took it off to get dyno tuned the guy said just leave them in. I didn't ask why, he's been tuning for over 20 years so I figured it was the best way to go...maybe it just made it easier on him? I don't know but I do know i get 40 miles to the gallon 2 up and the bike runs perfectly.

 

I was wondering what would happen if I reconnected them. Its running good so I think I'll just leave them disconnected. Taking grandpa's advice. Thanks.

 

Follow the ECM connector- chances are you'll find a Power Commander tucked in behind the splash guard/ ECM caddy. Plug them in, and soon you may have an O2 sensor "out of range" code, because they are trying to modify the signal that the power commander is modifying.

 

No PC tucked in anywhere. Could it be it had one then it was removed?

 

I have a good Fiend tell me " If it Aint broke Don't fix it"