O2 sensor? What if we just unplug it for the lean issues?

48261 Views 68 Replies 29 Participants Last post by SalekS, Sep 26, 2017

jgustman

Discussion Starter · May 13, 2013

First post here...had been running drilled stock pipes but just added V&H twin slash pipes and have a ejk tuner on the way. I put the pipes on and took it for a spin with the o2 sensor unplugged since I don't have the fuel programmer yet. I assume the ecu will default to a richer setting similar to the resistor mod for the o2 sensor...Or will it be too rich all over the rpm range? The test ride was only a few miles but seemed to run smoother with less chugging at low rpms in 1st/2nd gear and backfires on decel were not very bad at all. So just a thought for the stock owners looking to do the resistor mod...maybe just unplug it all together.:nod: Please chime in if this has been done, but my search turned up nothing. Maybe it will suck gas like crazy, but don't think so. I didn't ride the bike any more yet and will be a moot point when I get the controller as I have read the o2 sensor gets unplugged anyway.

21 - 40 of 69 Posts

Adrenaline Revolution

· #21 · Jul 15, 2013

ashtank23 said:
I'm still stock, engine wise. I plugged it back in tonight and it definitely pulls more with the 02 sensor in. Now i just have to decide whether I'd rather have more pull with surging or less pull and little to no surging. Hmm

Remember, The O2 sensor does not affect the mix under throttle so I can't imagine what is causing your bike to not pull with it unhooked.

Stryker2012

· #22 · Jul 15, 2013

I am almost tempted to get a 2>2 exhaust just to see what it is everyone seems to have a problem with. I got the Powrflo intake, Cobra4" slip-on exhaust and the auto-tuner, and the bike runs **** great!

yammyboy

· #23 · Jul 16, 2013 (Edited)

This is why I love forums on what you own. My new baby is surging and has a terrible on off throttle hit when closing and opening the throttle going into and out of a tight turn. I thought disconnecting the O2 harness would throw a code. Guess it wont. Ill have to test this out as my Stryker is totally stock untill its broken in. Ill report back when it stops raining.lol.

Stryker2012

· #24 · Jul 16, 2013

yammyboy said:
This is why I love forums on what you own. My new baby is surging and has a terrible on off throttle hit when closing and openingthe the throttle going into and out of a tight turn. I thought disconnecting the O2 harness would throw a code. Guess it wont. Ill have to test yhis out as my Stryker is totally stock intill its broken in. Ill report back when it stops raining.lol.

Not sure what you mean by on/off throttle hit. Are you sure it's not tranny lash? These transmissions seem to have more lash than other bikes have had owned. If your talking about a like a clunking when you get on and off, that is the transmission and is inherent. Especially if you are zipping along on a relatively horizontal part of the road and on decel the momentum of the bike slightly overtakes the speed of the engine. Then when you hit the throttle again, you get a clunk. Just need to adjust how you ride. Some say you can adjust the belt...some say take the play out of the throttle...I say it's all in how you clutch AND throttle.

Michael88997

· #25 · Jul 16, 2013

what are people getting MPG wise when they unplug it? thinking of unplugging mine to see if it gets rid of the chugging issue

toby

· #26 · Jul 16, 2013

Stryker2012 said:
Not sure what you mean by on/off throttle hit. Are you sure it's not tranny lash? These transmissions seem to have more lash than other bikes have had owned. If your talking about a like a clunking when you get on and off, that is the transmission and is inherent. Especially if you are zipping along on a relatively horizontal part of the road and on decel the momentum of the bike slightly overtakes the speed of the engine. Then when you hit the throttle again, you get a clunk. Just need to adjust how you ride. Some say you can adjust the belt...some say take the play out of the throttle...I say it's all in how you clutch AND throttle.

Exactly, don't throttle down into a turn. If you hit your turn too fast and must throttle down, Slip your clutch as you throttle up. That takes the drag off, lash catchup and throttle lag out. But the proper way to hit your turn is to slow before you start your turn and rap your throttle to get your rpm up as you down shift and maintain the rpm at a steady pase into the turn then slowly throttle up as you can:wink:

Something some of you guys are missing is the fact that the 02 sensor has a very small effect on how the motor runs and that is limited to two minimal points in operation. One of which has virtually no effect while the bike is in motion. These two points are at idle and idle cruise, when the bike is setting at a stop in neutral or clutch in, and when at a steady cruise speed with no drag or load on the motor.
As soon as you hit the throttle the closed loop mode opens and the 02 is no longer in play. So I would think that if you are having issues any where else there is something else wrong that needs to be adjusted, including the way you operate your bike. Even though they say these bike were designed to be ridden aggressively they are not a high performance race bike so they will have issues that can only be addressed by how you operate it.

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Stryker2012

· #27 · Jul 16, 2013

toby said:
Exactly, don't throttle down into a turn. If you hit your turn too fast and must throttle down, Slip your clutch as you throttle up. That takes the drag off, lash catchup and throttle lag out. But the proper way to hit your turn is to slow before you start your turn and rap your throttle to get your rpm up as you down shift and maintain the rpm at a steady pase into the turn then slowly throttle up as you can:wink:

Something some of you guys are missing is the fact that the 02 sensor has a very small effect on how the motor runs and that is limited to two minimal points in operation. One of which has virtually no effect while the bike is in motion. These two points are at idle and idle cruise, when the bike is setting at a stop in neutral or clutch in, and when at a steady cruise speed with no drag or load on the motor.
As soon as you hit the throttle the closed loop mode opens and the 02 is no longer in play. So I would think that if you are having issues any where else there is something else wrong that needs to be adjusted, including the way you operate your bike. Even though they say these bike were designed to be ridden aggressively they are not a high performance race bike so they will have issues that can only be addressed by how you operate it.

++++1 on everything Toby

DraEagWol

· #28 · Jul 16, 2013

With my O2 sensor unplugged - this last weekend the wife & I did a 2-up road trip... I averaged 41.7mpg - avg speeds 55-65.... back hiways... slowing down through little towns... etc.. etc...

I have the 30tooth pulley as well... as the cobra powerflo / & pro, and the V&H twin slash...

so... Hi-way mileage with a full load... (I'm fairly hefty - & the wife is just "right") ... not bad at all I think.... oh with batwing & LRS 11" shield & full bags.

Now my in town mileage is only bout 30miles to the gallon... to much stop & go....

toby

· #29 · Jul 16, 2013

Stryker2012 said:
++++1 on everything Toby

Let me also add that by using racing throttle and clutching techniques you deny the 02 sensor to ever lock into closed loop mode which locks out all other sensors. So on stock bikes there is really no need to unplug the 02.. But on molded bikes, especially with no cat, there should be no need for an 02 sensor unless you plan on doing long cruises and want gas economy.

bushboarder

· #30 · Jul 17, 2013

toby said:
Something some of you guys are missing is the fact that the 02 sensor has a very small effect on how the motor runs and that is limited to two minimal points in operation. One of which has virtually no effect while the bike is in motion. These two points are at idle and idle cruise, when the bike is setting at a stop in neutral or clutch in, and when at a steady cruise speed with no drag or load on the motor.
As soon as you hit the throttle the closed loop mode opens and the 02 is no longer in play.

Toby,

Just want to make sure I'm understanding this correctly. If I'm going say 30mph and holding the throttle steady, the O2 sensor is in play correct?

The reason I ask is I've had some surging in 1st and 2nd gear. Tonight I unplugged the O2 sensor and went for a 30 mile ride. Surging is much improved, almost gone actually.
I guess I'll run it unplugged until I get my Freedom exhaust installed and then try with it plugged in again.

Current set up is Cobra autotune, Cobra air intake, and drilled exhaust.

Goose0704

· #31 · Jul 17, 2013

What freedom exhaust are u getting the black curves or chrone

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bushboarder

· #32 · Jul 17, 2013

Goose0704 said:
What freedom exhaust are u getting the black curves or chrone

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Waiting on black sharp curves

Goose0704

· #33 · Jul 17, 2013

What's the date they gave u

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bushboarder

· #34 · Jul 17, 2013

Goose0704 said:
What's the date they gave u

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I ordered on may 24 and tentative date was early July. Obviously that has come and gone. Been really busy with work, and won't have time to install right now, so no big deal to me.

toby

· #35 · Jul 17, 2013

bushboarder said:
Toby,

Just want to make sure I'm understanding this correctly. If I'm going say 30mph and holding the throttle steady, the O2 sensor is in play correct?

The reason I ask is I've had some surging in 1st and 2nd gear. Tonight I unplugged the O2 sensor and went for a 30 mile ride. Surging is much improved, almost gone actually.
I guess I'll run it unplugged until I get my Freedom exhaust installed and then try with it plugged in again.

Current set up is Cobra autotune, Cobra air intake, and drilled exhaust.

Yes as long as you are not going up a slight hill there is no load so the 02 is at work. To better understand what roll the 02 may play in causing surging. When in first gear at slow speed there is very little wind resistance and as you reach a peak point holding your throttle steady the 02 is in play. It causes the ECM to go into a search or hunting mode to keep the A/F ratio at 14.7. It will drop below or go Above the 14.7 and you will feel a surging as it's trying to adjust . If there is any resistance or load read or your throttle moves slightly or even a gust of wind or bump in the road the ECM sends a richer mix and you will feel a surge then you will feel it shut down if you don't throttle up. This can be amplified by loose a belt, loose throttle linkage, maybe even low tire pressure, and also power mods.
Hope that answered your question and makes sense to you.

bushboarder

· #36 · Jul 17, 2013

Toby- Thank you.

Easy to understand with the example you provided.
I'll check belt tension also once I receive the tool.

Stryker2012

· #37 · Jul 17, 2013

bushboarder said:
Toby- Thank you.

Easy to understand with the example you provided.
I'll check belt tension also once I receive the tool.

As I'm sure Toby will attest to......I think it is a rarity that there is something truly wrong with the way the bike performs. For starters, it's a true V-twin, so it inherently has burps and farts. As long as it's not stalling at lights, or cutting out while cruising, etc., . Then when people do mods, the slight burps and farts are exaggerated...and then people aren't happy and spend more money trying to get the bike to run perfect again. I guess that is the major downfall of EFI. Instead of being able to set the carb(s) a little rich and letting it go at that, we have to fart around with talking to the darn ECM. In which for the most part, we're doing the same thing....making it run rich. So before you start pulling O2 sensors off, and buying tuners...try to differentiate if you have a real problem or whether it's the kind of bike you're riding

...and as far as doing mods in the future...I posted once before - the guy who puts a radical cam in his engine, then complains it won't idle smooth...can't have both.

Glad to see another Masshole

That makes three that I know of in this forum!

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yammyboy

· #38 · Jul 17, 2013

Well I unpluged the O2 harness and went for a ride with my girlfriend on the
Back. The bike is smoother by 75% now in the low speed area. Its not
Perfect. But a **** of alot better. Guess the trans has lot of play between
the gears. Ill have to get use to that. Oh gas mileage. I fill the tank to the
top. When the first O comes off its at 39 miles with the 02 sensor plugged or not.
gas mileage is the same.

toby

· #39 · Jul 17, 2013

Stryker2012 said:
As I'm sure Toby will attest to......I think it is a rarity that there is something truly wrong with the way the bike performs. For starters, it's a true V-twin, so it inherently has burps and farts. As long as it's not stalling at lights, or cutting out while cruising, etc., . Then when people do mods, the slight burps and farts are exaggerated...and then people aren't happy and spend more money trying to get the bike to run perfect again. I guess that is the major downfall of EFI. Instead of being able to set the carb(s) a little rich and letting it go at that, we have to fart around with talking to the darn ECM. In which for the most part, we're doing the same thing....making it run rich. So before you start pulling O2 sensors off, and buying tuners...try to differentiate if you have a real problem or whether it's the kind of bike you're riding ...and as far as doing mods in the future...I posted once before - the guy who puts a radical cam in his engine, then complains it won't idle smooth...can't have both.

Glad to see another Masshole That makes three that I know of in this forum!

One more thing that these guys are doing that makes the lash and other characteristics of this bike stand out more is their slow shifting habits. Pull the clutch in, let off the throttle, shift to the next gear, let the clutch out, roll on the throttle. :tsk: It only takes a second of the throttle to be closed with clutch puled in for the 02 to come into play. That's when you will get that hiccup when it goes back and forth from closed loop to open loop. Practice shifting faster. Put all the shifting movements together as one. Do all that simultaneously in a fraction of a second not letting the momentum of the bike to change, rpm drops only when it picks up the next gear, allowing NO tranny lash, belt slop or throttle lag to occur. And most importantly not letting the 02 to sens no load and lock into closed loop mode. I guess you can say the 02 adds one more thing to the catch up scenario

Stryker2012

· #40 · Jul 18, 2013

toby said:
One more thing that these guys are doing that makes the lash and other characteristics of this bike stand out more is their slow shifting habits. Pull the clutch in, let off the throttle, shift to the next gear, let the clutch out, roll on the throttle. :tsk: It only takes a second of the throttle to be closed with clutch puled in for the 02 to come into play. That's when you will get that hiccup when it goes back and forth from closed loop to open loop. Practice shifting faster. Put all the shifting movements together as one. Do all that simultaneously in a fraction of a second not letting the momentum of the bike to change, rpm drops only when it picks up the next gear, allowing NO tranny lash, belt slop or throttle lag to occur. And most importantly not letting the 02 to sens no load and lock into closed loop mode. I guess you can say the 02 adds one more thing to the catch up scenario

I totally agree. When I shift fast (if you listen to the exhaust, you can't even hear a pause in between gears) this bike is the smoothest thing going. If I shift slow, unless I'm real easy getting back on the throttle, it WILL clunk. Beautiful bike...just gotta learn how to ride it :nod:

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