Unplugging the 02 sensor?


34 replies to this topic
  • gnath9

Posted June 26, 2013 - 08:28 PM

#21

I am no mechanic but, I have been selling Ford parts for a very long time and have a good understanding of what they do .....

The O2 sensor senses the fuel to air mixture in the exhaust ... If it senses to much fuel then some type of EGR valve will route that mixture back thru the air box to be burned again. This has nothing to do with performance and has everything to do with emissions leaving the tail pipe.
Just simply unplugging it is not the answer. The performance car guys purchase a dummy sensor that always sends a "fake" signal to fool the processor.

I am sure our good buddy TNT could explain this way better than I can.

  • r6realtor

Posted June 26, 2013 - 08:43 PM

#22

ok just pulled this from rick ramsey site, now I see what tro1086 was saying, and I do think that this would enrichen the mixture, ecu should take over, by unplugging sensor the ecu will think it is under a load there by continually enriching the mixture, am I dreaming here or does that make any sense?? I'm a pollock so lots of things that don't make sense to most make sense to me lol!

EXPAND
O2 sensor is used for emissions only
open vs closed loop
WOT
FI controllers
EJK/Dobeck
Bazzaz ZAFM ZFi
DynoJet DFC
DynoJet:
A typical production vehicle uses oxygen sensors that have a very narrow resolution. When you are cruising / idling (closed loop), the vehicle is concerned with maintaining an A/F ratio of 14.7 (stoich). When you put your foot on the floor and go into power enrichment (open loop), the factory sensors do not have enough resolution to tell you an exact A/F ratio. Any system that ties in to the factory oxygen sensors can only tell you if you are richer or leaner than 14.7. The Wide Band Commander, utilizing the Bosch LSU4 wideband sensor, will tell you exactly what A/F ratio you are running.
Oxygen sensor - from Wikipedia
When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensor is ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage. This is referred to as an engine running in 'open-loop mode'. Any changes in the sensor output will be ignored in this state. In many cars (with the exception of some turbocharged models), inputs from the air flow meter are also ignored, as they might otherwise lower engine performance due to the mixture being too rich or too lean, and increase the risk of engine damage due to detonation if the mixture is too lean.
Check w/C

Edited by r6realtor, June 26, 2013 - 08:51 PM.


  • Tro1086

Posted June 26, 2013 - 09:15 PM

#23

Yea if TNT would chime in I think he knows a lot on this subject. All my experience is from EFI on vehicles and the bike may be programed differently.

As far as the the 02 sensor being used to open or close an EGR valve, these bikes have no EGR system.

The O2 sensor is used to control the fuel to air mixture. By detcting the ammount of oxygen(O2) in the exhaust it can tell how rich or lean the engine is. It then gives this signal to the computer and it decides if it should inject more or less fuel.

Open or closed loop, it short, just basically means the computer is either using the O2 sensor to determine mixture, or it is running on a preset fuel map. Closed loop is when the O2 sensor is used to calculate fuel. Open loop is when the engine is using sensors such as Throttle Position, Air Flow, Intake Air Temp, Coolant Temp, etc, to determine its fuel map. On a car in order for closed loop (O2) sensor to be used, some criteria must be met. The O2 sensor must be up to temp and sending signal to the ECU, and engine coolant temp must be above a certain range, also it will only stay in closed loop(O2) when you are in certain throttle ranges. When you go to 0 throttle it will go into open loop, and also when you go over a certain throttle opening it will go into open loop. Most vehicles are different, some will switch to open loop (no O2) at 60% or higher throttle, some are higher. My Tacoma switches at 85% throttle, and you can actually feel it. Mine actually has LESS power in open loop because its TOO rich. Most open loop/preset fuel maps are fudged to be more on the rich side. An engine running to rich is MUCH safer than an engine running to lean. If you run TOO lean you can melt pistons and valves. If you run to rich you just have poor power and waste fuel. The point of the 02 sensor is that it can keep the engine at a more precise fuel mixture. But in order to protect the engine when you go full throttle, maximum air intake, the manufactures have it switch to open loop where it will run more on the rich side. It may also switch to open loop above a certain RPM, but I am not sure.

What Im getting at is, if the bike acts anything like the fuel injection in a car, then once you go past a certain throttle opening, the ECU is already "unplugging" the 02 sensor for you, and running on a preset, richer, fuel map So by unplugging the O2 sensor all you are doing is adding more fuel when you are just cruising, and not really asking for more power anyway.

Again, 95% of my EFI knowledge is from automobiles, so the bike could be different in some ways. But I imagine for the most part it probably acts very similar to the EFI in cars.

All we can really do is try it for ourselves and make our own conclusion. I think the only real down side you could have from unplugging it is less MPGs. It sure would be easier to try it out if I HAD THE DANG BIKE ALREADY!!!! Cant wait to get mine!! I should be getting mine friday too, but Iv already got the Stage 1 waiting to go on it, Megabomb, PC4, EJK, hehehe.

  • hockeyrick

Posted June 26, 2013 - 10:03 PM

#24

well i don't plan to do any exhaust possibly a programmer, but would like to keep this one mainly stock because I will mainly be in the woods with it, I have done all the programmer/airbox/exhaust/emission removal to my other bike and she is a beast..a loud beast and i think this time around im gonna stay mainly stock for the woods (minus sprockets) however if I can get a bit more fuel to it stock it may help a little
Posted Image


Is this your bike? a motard woods bike? kind of an oxymoron, isn't it?

  • Tro1086

Posted June 26, 2013 - 10:11 PM

#25

I think thats his supermoto, and he is getting the 250L for the woods, haha.

  • r6realtor

Posted June 27, 2013 - 02:43 AM

#26

Is this your bike? a motard woods bike? kind of an oxymoron, isn't it?

Yes this is my bike and no it's obviously not a woods bike, tro1086 has got it that's what the CRf will be for is the woods, I was just showing that I have been there done that with the exhaust/programmer/tons of money in mods route on this bike and just think I'm going to keep the CRf mainly stock, I know it will much more tame without all the mods but it will be nice and quite!
Tro1086 thank you for the explanation on the sensor stuff!!!!

Edited by r6realtor, June 27, 2013 - 04:44 AM.


  • Cat ji

Posted June 27, 2013 - 03:49 AM

#27

yes, with standard exhaust it would be quite quiet. :)

  • r6realtor

Posted June 27, 2013 - 07:24 AM

#28

well my buddy just came over and he unplugged his for a couple of test runs and SWEARS it is better, feels like it revs out better. I asked him specifically are you sure your not dreaming??? he swears it made a difference!

  • Crfsfan

Posted June 27, 2013 - 06:31 PM

#29

Tro1086, great explanation of the o2 sensor, open loop, closed loop. Thanks for the info.

  • greg11

Posted July 22, 2013 - 06:27 PM

#30

Anyone know a good online source for sprockets that ships to Canada? Also, what's a good company/manufacturer? I hear tell of JT, Renthal and others, but no idea what to get!!

  • Dago52

Posted July 22, 2013 - 06:33 PM

#31

Anyone know a good online source for sprockets that ships to Canada? Also, what's a good company/manufacturer? I hear tell of JT, Renthal and others, but no idea what to get!!


I used sprocket center.com and Chad was very helpful. I don't know about the shipping though. Give them a call and I am sure he can make something happen.

  • breambuster

Posted July 23, 2013 - 11:08 AM

#32

well i don't plan to do any exhaust possibly a programmer, but would like to keep this one mainly stock because I will mainly be in the woods with it, I have done all the programmer/airbox/exhaust/emission removal to my other bike and she is a beast..a loud beast and i think this time around im gonna stay mainly stock for the woods (minus sprockets) however if I can get a bit more fuel to it stock it may help a little
Posted Image


What kind of mirrors are those????? Could I do this to the L??? I hate the stock mirrors.

  • Cat ji

Posted July 23, 2013 - 12:55 PM

#33

Look for previous posts by R6realtor, all shall be revealed.
Mine are on their way to me. :)

  • r6realtor

Posted July 23, 2013 - 01:30 PM

#34

yes can definitely be done
Posted Image
Posted Image

Edited by r6realtor, July 23, 2013 - 01:36 PM.


  • Cat ji

Posted July 24, 2013 - 07:13 AM

#35

btw, i got my mirrors today. Quite well made for the price. And i got fancy 3M Motion Pro rim tape (instead of the rubber strips) and 7/8" Cycra handguard clamps. :)





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