Hi all,

new member here so i hope i'm posting this in the right place.

I have a 2009 FXDL and i have just changed the exhaust and i have a challenge with the O2 sensors. My bike was fitted with the 2 wire sensors and the new (but pre loved) system i have just fitted has the 4 wire sensors. can i do a cut and splice to adapt the 'new' sensors into my harness and if so, which wires do i need to use? Thanks in advance

 

If you are talking about a new head[pipe?! Just use the sensors that you had before. pretty sure the two wire are narrow band. 4 wire would be wide band heated. The two are not cross compatible, unless you change the ecm, or buy a piggy back wide band interpreter, like the power vision auto tune.

 

I think the heated 4 wire are still narrow band but that isn't perhaps the biggest issue. The old 2 wire were M18 so won't fit. Plugs are available for fitting the newer M12 threaded sensors into old exhausts.

Maybe you can get someone to change the fitting to suit the bigger sensor.

 

So just to clarify, my bike is fitted with the 2 wire M18 sensors, the new header pipes have the M12 4 wire sensors. i was hoping that i'd be able to just use which ever of the 4 wires i needed and just insulate the other 2 wires (for the heater), the header pipes only have the M12 boss to accept the M12 sensor. i'm sure with enough money i can pay someone to drill them out and weld in the M18 bosses but i was hoping there would be an easier solution by adapting the 4 wire sensors to the 2 wire harness

 

It might work by not connecting the system power and heater ground wire. After a quick read the idea is the heater allows the sensor to give reliable readings from the get go at a constant temperature.

Looking at the way the HD EFI works though closed loop control isn't happening at startup with a cold engine.

From our friend!

If the heater fails, the O2 sensor may still give feedback to the ECM but this process will take more than the standard time of less than two minutes. This can result in an engine stalling or running inadequately, increased fuel consumption, and the accumulation of carbon.

Try it and see what happens.

 

thanks for the advice, i've found some wiring schematics online and i have the service manual for my bike so i should be able to integrate them and see how it goes.

on a side note, i fitted some O2 eliminators and she rides just fine - i'm only concerned about it running lean at any point and creating trouble of the expensive kind!

I'll fill you all in on my findings.

 

well they say no guts - no glory. looking through the wiring diagrams and the information supplied by chatting to everyone and anyone i decided to leave the 12mm sensors on my bike, eliminate the extra two wires that come from the sensors and just graft the other two wires into my existing harness. now i'm aware that the 12mm O2 sensor uses a 'heater' which is what the other two wires are for so initially on start up she does give a puff of black smoke - nothing to get upset about. by the time i put my helmet, jacket and gloves on, she's been warming up for a minute or two and has shown no sign of issue in the past 4 weeks. admittedly i've probably only ridden one full tank worth. i'm hoping that everything stays well. if for some reason i've made a bad choice and i melt my engine... well a good excuse for some extra cubes then!