O2 sensor crosstalk?
Tourer
Joined: Dec 2006
Posts: 492
Likes: 0
From: Castle Rock, CO
O2 sensor crosstalk?
In all of the de-catting threads, the O2 sensor crosstalk boogie man is invariably thrown in, but I haven't seen anyone describe what negative issues it would cause, yet.
Soooooo, what should I have been seeing for the last 30,000 miles? Rough running, less gas mileage, engine codes - what am I missing?
Soooooo, what should I have been seeing for the last 30,000 miles? Rough running, less gas mileage, engine codes - what am I missing?
Road Warrior
Joined: Jun 2008
Posts: 1,437
Likes: 80
From: currently an Okie
Cross talk
From a control perspective, the two cylinders are two independent closed loop control circuits. The potential is that each individual cylinder wouldn't be as optimally tuned if the O2 sensor is reading a portion of the other cylinders exhaust gas.
One thing that makes me doubt it is an issue is I saw were someone gutted his cat and the bike wasn't running right after that. He then discovered he had switched his O2 sensors. When he put the right O2 sensor to the right exhaust port he was good to go.
That's a good indication that the O2 sensors are not being influenced by the wrong exhaust (at least when you have them in the right ports).
That would be a good test for anyone worried about it. Just swap your O2 sensors and see if the bike starts running bad.
One thing that makes me doubt it is an issue is I saw were someone gutted his cat and the bike wasn't running right after that. He then discovered he had switched his O2 sensors. When he put the right O2 sensor to the right exhaust port he was good to go.
That's a good indication that the O2 sensors are not being influenced by the wrong exhaust (at least when you have them in the right ports).
That would be a good test for anyone worried about it. Just swap your O2 sensors and see if the bike starts running bad.
Thread Starter
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Ultimate HDF Member
Joined: Feb 2010
Posts: 8,039
Likes: 1,305
From: Jayhawk Country
I read your thoughts, sorry! Must be the crosstalk between our O2 sensors.
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Road Warrior
Joined: Apr 2010
Posts: 1,255
Likes: 1
From: Superior, WI
What I really don't get is people go out and spend 20+ thousand dollars on a motorcycle, baby it, wash it all the time.....and then try to do the cheapest mods possible. I understand the economy is rough and parts cost money. That's why I ran my CAT for almost a whole summer while I saved up for a new header. I bet if most riders added up the amount of bolt on chrome they have on their bike, it would be less expensive than a new header from Fuel Moto, Vance & Hines, or Fullsac.
When you cut out the CAT, you basically have a 4" tube for a collection chamber. While yes, it will run cooler, and yes it will sound louder (the main reason 99% do the mod, we want our bikes to sound like Harley's again), it is an incredibly inefficient collection chamber. There is a reason and engineering that Fuel Moto and Fullsac talk about the angle of the collection chamber, diameters, etc, etc. It was engineered to run perfectly with your motor.
If you are looking for an inexpensive mod, search Ebay for 09 headers. Most can be had for a very reasonable price. There is a bid on Ebay right now for a set for 25 bucks.
I am not bashing those that do it. I just don't get why people spend a TON of money on their bikes, only to do half-a$$ mods to it, yet still call it their pride and joy. Different strokes for different folks I guess.
Like I said I am not bashing it. I hope those that have done it do not run into any issues and gives them a smile every time they ride.
When you cut out the CAT, you basically have a 4" tube for a collection chamber. While yes, it will run cooler, and yes it will sound louder (the main reason 99% do the mod, we want our bikes to sound like Harley's again), it is an incredibly inefficient collection chamber. There is a reason and engineering that Fuel Moto and Fullsac talk about the angle of the collection chamber, diameters, etc, etc. It was engineered to run perfectly with your motor.
If you are looking for an inexpensive mod, search Ebay for 09 headers. Most can be had for a very reasonable price. There is a bid on Ebay right now for a set for 25 bucks.
I am not bashing those that do it. I just don't get why people spend a TON of money on their bikes, only to do half-a$$ mods to it, yet still call it their pride and joy. Different strokes for different folks I guess.
Like I said I am not bashing it. I hope those that have done it do not run into any issues and gives them a smile every time they ride.
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Outstanding HDF Member
Joined: Jan 2010
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From: earth
At this point in time O2 cross talk is just a theory, but one that I subscribe to. So far no one has published any measurable findings to support either side of the argument, myself included. Many claim "no problem" after XXXX miles, but how would you know, without some kind of recorded feedback? Because it "feels" right, hell most can't feel the difference between XIEDs, a canned map, and a real tune, except the guys who have eventually upgraded to proper tune. No issue from O2 cross talk is an unfounded claim, like the guys who think they can tell the tune condition of their EFI bike by looking at the sparkplugs. I prefer to lean to the side of safety on the topic because there is potential for the crosstalk. If it is happening, it would result in imprecise fuel management similar to a carburetor, because your O2 feedback would be the average of both cylinders, from both sensors, so with "averaged" feedback your ECM can't make the correct individual cylinder adjustments to achieve the target map. I've been playing with my own tuning for several years and what I have noticed is that everything effects your tune condition; gas from a different station, a clean air filter, extreme swings in ambient temperature, humidity, elevation, you name it you can see it in the data logs. For that reason I'm not going to take a chance with cross talk, if it doesn't happen or doesn't exist, great, nothin lost by steering clear of a potential variable that could make tuning impossible. It takes a lot of time and effort to achieve a proper tune, so I dont need hard evidence about O2 cross talk one way or the other to make the decision to eliminate a suspicious variable from my tuning operation. You can buck up on either side of the argument but without any real supporting evidence there is no debate, just a bunch of people wasting energy on a moot point.
