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Discussion Starter #1
I am somewhat confused. I am not sure if the person who sent me this info knows what he is talking about, but he now has me concerned. I removed the cat from my stock exhaust header. My motor is otherwise bone stock except I am running cobra slip ons. I have not done the stage one nor am I running a tuner. After I did the cat removal I had two occassions where the bike refused to run after I turned it off then immediately tried to turn it back on. It appears it got hot and went into limp mode, one of the times I held the throttle open and it did start but only ran on one cylinder. Both times I was riding a road along a river at less than 25 MPH for several miles. Once I allowed the bike to sit for about 5 minutes it started and ran fine. So I posted this to see if the cat removal could cause it to run hot. I got a response telling me to make sure I put the right oxygen sensor in the right hole. He told me grey to the front and black to the rear. The problem I have is the wires on both sensors have the same colored wires (I think, its hard to get in there), and I dont see any other colored marking on them although they are hard to get to. Does this make any sense to anyone and if so, can this cause an overheating issue? And if so, how do you tell which is which? I have a very long ride this weekend with a large group and really dont want any issues with my bike. By the way it is a 2011 RGU with 7000 miles and I do have my lowers on. Any help is greatly appreciated.
 

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My guess would have been the O2 sensors in the wrong hole also if as you said there have been no other mods made. I have had no issues since removing my cat and like yours mine is bone stock except for the slip-ons.

Sorry I can't add any other insight except maybe disconnecting the negative battery cable and then re-attaching it to see if the ECM re-sets.
 

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The sensors have the same color connectors, but the connectors on the bike's wiring harness are different colors. I don't remember if they are located under the seat or the right side cover. Mine are under the right side cover now, but I don't remember if that's where they were before I added the wide band sensors.


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If the O2 sensors were hooked up incorrectly the bike will have issues with the way it runs all the time. From your description of the problem your experiencing, it sounds like the motor is overheating and going into limp mode. I know this sounds like a broken record, but most times any change in exhaust and or intake on the new bikes needs to be addressed with some type of fuel adjustment. Especially in hot climates such as Texas.
 

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The connectors under the right side cover are color coded. Make sure they are plugged in correctly and FULLY plugged in. Then trace the wires to the sensors and make sure they are plugged into the correct holes. The holes are marked "G" and "B" for grey and black.
 

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Make sure the wires to the sensors have room to flex and aren't tight or hung up on anything. As PGR said, the actual connectors are color coded and in plain sight under the right side cover. The head pipe has an 'F' and an 'R' next to the bungs.
 

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another factor that I have read with removing the cat is crosstalk between the two sensors

Urban legend...... If you open up the pipe, the sensors are ahead of the cat. Removing the cat does not affect the sensors in any way. They are also separated by the tube, as seen in this picture.

The sensors are being played by sharpies in this post catectomy pipe. As you can see, there is no way they could talk to each other.

 

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I would not say there's no way, because reversion stirs things up pretty good... But I would say it's unlikely much different than when the CAT was there.

Certainly wouldn't expect cross talk to be creating the issue the OP has encountered.
 

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I would not say there's no way, because reversion stirs things up pretty good... But I would say it's unlikely much different than when the CAT was there.

Certainly wouldn't expect cross talk to be creating the issue the OP has encountered.

If you have enough reversion to mix gasses from one tube to the other, you are running serious high lift cams. In that case running decatted stock pipes would be kind of defeating the purpose of spending the money on cams..

And you are right.... it would be no different than when the cat was still there. But if there was a difference, you would think that not having anything in the way of the outflow, with the cat gone, would create LESS cross talk.
 

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Discussion Starter #11
If the O2 sensors were hooked up incorrectly the bike will have issues with the way it runs all the time. From your description of the problem your experiencing, it sounds like the motor is overheating and going into limp mode. I know this sounds like a broken record, but most times any change in exhaust and or intake on the new bikes needs to be addressed with some type of fuel adjustment. Especially in hot climates such as Texas.
So, that opens a whole new conversation, because half of the posts on here say changing exhaust does not require any modification to the map and the other half says it does. I plan to do the stage one download, but have not made a decsion on air cleaner or final exhaust yet and dont want to spend $300.00 until I make a decision. But also dont want problems with my bike. I traded in my 2000 EG Ultra because it was a constant problem. Dont want to start all over with this one. I would rather put my cat back on if that is the case (I decatted a headpipe off my buddies bike but kept my original).
 

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If you have enough reversion to mix gasses from one tube to the other, you are running serious high lift cams. In that case running decatted stock pipes would be kind of defeating the purpose of spending the money on cams..

And you are right.... it would be no different than when the cat was still there. But if there was a difference, you would think that not having anything in the way of the outflow, with the cat gone, would create LESS cross talk.
Agreed I was thinking the same thing about less without the CAT material... that said, if the slip-ons are changed at the same time and creating a reflection it could get worse depending.

Of course all this is crazy talk with stock no overlap cams. :)
 

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So, that opens a whole new conversation, because half of the posts on here say changing exhaust does not require any modification to the map and the other half says it does. I plan to do the stage one download, but have not made a decsion on air cleaner or final exhaust yet and dont want to spend $300.00 until I make a decision. But also dont want problems with my bike. I traded in my 2000 EG Ultra because it was a constant problem. Dont want to start all over with this one. I would rather put my cat back on if that is the case (I decatted a headpipe off my buddies bike but kept my original).
Forgive me if you know this already... <this is my understanding of how the system works>
Dephi ECM Targets a specific air fuel value using closed loop as much as possible. The ECM calculates the amount of fuel to achieve the target. O2 sensors are the feedback loop, they tell the ECM whether the Target is met or missed. If missed, the ECM uses Adaptive Fuel Value to adjust the fuel delivery to meet the Target. AFV only has +/- 10 points of range before it can no longer keep up. So it's possible to exceed the ability of the ECM to adjust fuel level. If you're lean, you're running way hotter and run the risk of over heating. That's one problem area. The other problem area is that the ECM has fixed values for how much more fuel it dumps into the system when in Open loop, ie warm up, acceleration, over heating, heavy load situations. But if the engine is passing enough air to surpass the fixed values you're going to run lean under those conditions too. That's where you run the risk of hurting the engine.

A tuner is a good idea for numerous reasons, even if you aren't going to make any drastic changes, which have already been shared many times on this and other forums. Heat management, driveability and improved throttle response being the biggest reasons.

I still think you should check the O2 sensor wiring to insure you don't have a simple problem like a broken or damaged wire.
 

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Harley must adhere to EPA emissions as we all know. That means your motor is set to 14.7 to 1 AFR (stoichiometric) when in closed loop operation. That is already a lean mixture for an air cooled motor. Now consider if your available fuel has a 10 percent alcohol content that stoichiometric number changes to 14.3 to 1 ratio which makes your a/f mixture even leaner. My point is that any change that moves more air thru the motor needs to be addressed, and if your climate is hot the probability of having the effects your experiencing multiply.
 

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Urban legend...... If you open up the pipe, the sensors are ahead of the cat. Removing the cat does not affect the sensors in any way. They are also separated by the tube, as seen in this picture.

The sensors are being played by sharpies in this post catectomy pipe. As you can see, there is no way they could talk to each other.

Damn I can't believe everything I read on the Internet? And my Nigerian prince is fake?

Great explanation I book marked it for future reference



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Discussion Starter #18
A lot fo very good information. I appreciate all the input. I think I will go ahead and get a programmer. At least that way when I do add the air cleaner, etc I am ready to go. Thanks everyone.
 
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