O2 sensor eliminator ? why?

[Guth_imp]

It turns out that I've been doing a bit of lurking here on the forum. Reading with interest the posts of others who have installed an O2 sensor eliminator. The reason for this? My CB1100 had been exhibiting fairly poor fueling characteristics at levels below approximately 3000 RPM. Each ride would end the same way: with me cruising down the street all herky jerky 'til I pulled into the driveway and shut it down. Now to be fair, while this feels like a big deal to me when I'm on the bike, I have no idea whether or not someone watching me pass by would notice this at all (or whether or not they could hear the throttle hunting in my exhaust for that matter).

At any rate, I recently went ahead and ordered an O2 sensor eliminator. Got it installed in just a few minutes. Took the bike for a quick spin around the neighborhood, just putting along nice and slow. It was like night and day. The fueling was incredibly smooth. Next I'll need to get the bike nice and warmed up and see if that makes a difference. I'm hoping that the fueling will remain smooth and steady. That's all I'm really interested in. I'm not concerned about performance gains. I'm hoping that I don't see a decrease in gas mileage.

But my question is this: why the need for this small contraption? It would seem that most here are happy with the fueling on their CBs, some reporting that it's close to perfect. Some report otherwise, a few of which have turned to solutions like the eliminator unit. Could this indicate that some of us have had O2 sensors go bad (or seriously fouled)? I'd be curious to see how my bike would respone to a replacement sensor. However that would be a far more involved not to mention a much more expensive test than just installing an eliminator plug. I guess you could say that my curiosity has only been partially satisfied.

What think ye knowledgeable forum members?

I've got the same problem you have, the low RPM performance is all herky-jerky and definitely not smooth. It reminds me of how my old '74 VW ran with ethanol in the gasoline. Keep us posted on your results because I'm interested if this might be a solution to our problem. Oh, and how about a link to the one you bought?

The commute to and from work today was much more enjoyable as a result of having installed the O2 eliminator.

As far as which one I went with: I bought one of the units, from Redline Superbikes. It is the kit that included the parts for removing the O2 sensor from the exhaust.

 

[metalmaven_imp]

Thanks for the post Guth, I have noticed the same jerky throttle at low rpms in 1st and 2nd gear also. Always bothered me but I thought it just was what it was. I am going to try this.

 

[mininsx_imp]

Mininsx,

Did you try the TPS reset procedure first? It seems to work for me and many others to smooth out low speed throttle response.
In case the procedure stops working for me, I purchased a Sensor Eliminator from Redline Superbikes in England:

http://www.ebay.ca/itm/o2-Oxygen-Lambda-...d3&vxp=mtr

Or this model which includes a screw and washer to replace the Lambda Sensor in the exhaust:

[url=http://www.ebay.ca/itm/o2-Oxygen-Lambda-Sensor-Eliminator-Set-Blanking-Plug-HONDA-CB-1100-2013-2014-/221639679815?pt=LH_DefaultDomain_3&hash=item339ac11f47&vxp=mtr]http://www.ebay.ca/itm/o2-Oxygen-Lambda-...47&vxp=mtr

Yeah, I've done that several times and it smooths out some but not completely. I've learned to live with it but if I can eliminate it that would be great.

 

[CIP57_imp]

I though about eliminating the O2 when i added the aftermarket exhaust but saw no positives only negatives. Running without it gives you a straight line A/F ratio (similar to a bike with carbs) , not able to compensate for elevation changes, cold, hot, low/high humidity. Piggyback controllers even have the ability to add there O2 as an add on.

But hey, if the bike runs better go for it

 

[ChipBeck_imp]

Gentlemen,

This is strange. Guth and I have the exact same bike, same model year, same exhaust. But my engine is as smooth as silk at all RPM's. It runs so nicely that I don't want to put my K&N filter on or make other minor changes that might screw it up. It almost has to be a fouled O2 sensor as the only other possibility is a most unlikely computer fault. Bill have you ever run leaded fuel in your bike? One other possibility is a frayed or shorted out wire coming from that sensor. I know you ride in the rain pretty often and perhaps water has corroded or shorted something out. If that O2 sensor eliminator has everything running fine then it is a moot point. I'm curious to know if your bike will still run as well at high altitude or will it run rich. The next time you ride up that big mountain in your area please report in. Cheers.

Chip

 

[Toro5xi_imp]

I also would recommend checking the TPS sensor position as someone else suggested. It is a 3 wire potentionometer which has a 5 volt reference signal provided by the ECU. It's function is to let the ECU know what type of load the engine is under along with the MAP sensor. Under conditions of light load and high manifold vacuum ignition timing is advanced as the flame front travels slower. On both my bandit 1200 and Bonneville the TPS was out of adjustment. Not sure on the CB but on those bikes just losen 2 screws and rotate the TPS. Made a nice improvement in off idle response.
O2 sensors today seldom go bad. It is a long shot but an exhaust leak can cause what is called a false lean reading. As the exhaust pulses pass the exhaust leak the resulting low pressure zone will pull in fresh air. The O2 sensor will see this and send a low voltage signal to the ECU. To check hook up a multimeter to the O2 sensor and use propane to see if the voltage signal consistently stays above or below .5 volts. This is the shade tree method but I never could justify the 5 grand for a 5 gas analyzer. You want to use the pre cat O2 sensor for this.
Good luck. Drivability issues can be maddening but it is fascinating I think to try and figure out the issue and very satisfying when fixed.

 

[the Ferret]

HUH ???????? Holy cow that was like reading a Kevin Cameron article. Lol

 

[Toro5xi_imp]

The electronics make sense once you understand what they are trying to accomplish. I am just a bean counter accountant but went to tech school at night to learn more about this stuff. The hard part I think is having access to the information and tools such as a scan tool and gas analyzer. The guys over on the Triumph rat forum really dig into it. Glad to say my CB has been flawless. Hit the starter and go. Love this bike.

 

[Guth_imp]

I'll eventually make my way to my favorite local independent shop to get things checked out with tools that I don't have. Like others, I don't exactly find the O2 sensor eliminator to be a desirable long term solution for reasons already mentioned above.


Sent from my iPhone using Tapatalk

 

[Toro5xi_imp]

Good luck Guth. Bummer when the Bike is not running like you want. Did the issue show up under warranty? Just curious if the dealership had any suggestions.

 

[ChipBeck_imp]

I also would recommend checking the TPS sensor position as someone else suggested. It is a 3 wire potentionometer which has a 5 volt reference signal provided by the ECU. It's function is to let the ECU know what type of load the engine is under along with the MAP sensor. Under conditions of light load and high manifold vacuum ignition timing is advanced as the flame front travels slower. On both my bandit 1200 and Bonneville the TPS was out of adjustment. Not sure on the CB but on those bikes just losen 2 screws and rotate the TPS. Made a nice improvement in off idle response.
O2 sensors today seldom go bad. It is a long shot but an exhaust leak can cause what is called a false lean reading. As the exhaust pulses pass the exhaust leak the resulting low pressure zone will pull in fresh air. The O2 sensor will see this and send a low voltage signal to the ECU. To check hook up a multimeter to the O2 sensor and use propane to see if the voltage signal consistently stays above or below .5 volts. This is the shade tree method but I never could justify the 5 grand for a 5 gas analyzer. You want to use the pre cat O2 sensor for this.
Good luck. Drivability issues can be maddening but it is fascinating I think to try and figure out the issue and very satisfying when fixed.

Gentlemen,

I was going to write this exact same thing but Toro beat me to it. Darn!!

Chip

 

[Toro5xi_imp]

I would really like to hear the result when Guth gets this corrected. Most of the drivability work I have done has been with cars and without the factory information it would have been tough to know what to correct. I would think if these issues have been reported before Honda would have a fix such as a new fuel map or timing chart to down load.
I agree with Guth that eliminating the O2 sensor may not be the best long term correction. in closed loop operation the O2 sensor provides important information to the ECU so that it can maintain the proper air/fuel ratio. In the old days we would mask these problems by dumping more fuel into the motor by putting a hole in the MAP sensor tube so the ECU saw less vacuum and thought the throttle was open more than it was thus the injector pulse width was increased. This worked for a while but resulted in higher levels of pollution and I often failed emission testing.
If it was not raining in Cleveland Ohio all day I would be riding instead of rambling on. Sorry

 

[Chapomis_imp]

ACK, you following this ???

 

[ChipBeck_imp]

I would really like to hear the result when Guth gets this corrected. Most of the drivability work I have done has been with cars and without the factory information it would have been tough to know what to correct. I would think if these issues have been reported before Honda would have a fix such as a new fuel map or timing chart to down load.
I agree with Guth that eliminating the O2 sensor may not be the best long term correction. in closed loop operation the O2 sensor provides important information to the ECU so that it can maintain the proper air/fuel ratio. In the old days we would mask these problems by dumping more fuel into the motor by putting a hole in the MAP sensor tube so the ECU saw less vacuum and thought the throttle was open more than it was thus the injector pulse width was increased. This worked for a while but resulted in higher levels of pollution and I often failed emission testing.
If it was not raining in Cleveland Ohio all day I would be riding instead of rambling on. Sorry

Toro,

Joking aside, your posts are really good stuff though a bit beyond my comprehension. I have one question. If it is the throttle position sensor, why would eliminating the 02 sensor fix Guth's drivability problem? Why would getting rid of that sensor fix any other problem?

Chip

 

[Toro5xi_imp]

I am speculating but I think that with the O2 sensor eliminated the computer is operating in open loop. In open loop the computer uses predetermined fuel maps which are slightly rich. The 2 main systems are speed density or mass air flow. With speed density the main inputs are RPM and Manifold Absolute Pressure. Mass Air flow uses a meter to actually try and measure the mass of air entering the engine. When the O2 sensor reaches 600 degrees the system goes into closed loop and primarily uses the voltage from the O2 sensor to adjust what is called the fuel trim to achieve 14.7 to 1. I am going off memory and I am sure it has advanced since I worked on this stuff. In open loop the fuel tables are slightly rich which is why the auto companies try to get the car into closed loop as soon as possible. This drove the need for O2 sensors with heaters in them. Rich can mask a lot of issues but creates more pollution. It could be that in closed loop one of the sensors like the engine coolant sensor is faulty.
I am still leaning towards the Throttle Position Sensor but it is hard to know. On my Bandit 1200 the TPS effected ignition timing only. I do not know if Honda is also using it to effect injector pulse width.
This is where I think the dealer would be the most help. There may be a technical service bulletin but at the very least they have flow charts which will guide the technician in his diagnostic process.
I just looked at the Power Commander site and it does state the Sensor eliminator prevents the ECU from going into closed loop operation. Hope this helps. I think some of the earlier posts did a great job explaining closed loop operation as well.

 

[SanPete_imp]

Here I was thinking I am an accomplished mechanic by doing my own oil change. What did he say?

 

[Toro5xi_imp]

Without the schematics and scan tools I think it is very tough to work on the electronics anymore. The dealer technicians also work with it everyday and stay up to speed with the latest advancements and information. I happily leave electronic trouble shooting to those guys now.

 

[ChipBeck_imp]

I am speculating but I think that with the O2 sensor eliminated the computer is operating in open loop. In open loop the computer uses predetermined fuel maps which are slightly rich. The 2 main systems are speed density or mass air flow. With speed density the main inputs are RPM and Manifold Absolute Pressure. Mass Air flow uses a meter to actually try and measure the mass of air entering the engine. When the O2 sensor reaches 600 degrees the system goes into closed loop and primarily uses the voltage from the O2 sensor to adjust what is called the fuel trim to achieve 14.7 to 1. I am going off memory and I am sure it has advanced since I worked on this stuff. In open loop the fuel tables are slightly rich which is why the auto companies try to get the car into closed loop as soon as possible. This drove the need for O2 sensors with heaters in them. Rich can mask a lot of issues but creates more pollution. It could be that in closed loop one of the sensors like the engine coolant sensor is faulty.
I am still leaning towards the Throttle Position Sensor but it is hard to know. On my Bandit 1200 the TPS effected ignition timing only. I do not know if Honda is also using it to effect injector pulse width.
This is where I think the dealer would be the most help. There may be a technical service bulletin but at the very least they have flow charts which will guide the technician in his diagnostic process.
I just looked at the Power Commander site and it does state the Sensor eliminator prevents the ECU from going into closed loop operation. Hope this helps. I think some of the earlier posts did a great job explaining closed loop operation as well.

Toro,

3 more questions.

1. So the CB11 should get slightly better mileage with the 02 sensor working right?

2. Is it the 02 sensor that leans out fuel to keep the bike at 14.7 to 1 in the thinner air at high altitude?

3. Would a CB11 ever run poorer with the 02 eliminator or would it just run slightly rich sometimes?

Thanks.

Chip

 

[Toro5xi_imp]

The absolute best performance occurs at a slightly richer mixture than 14.7 to 1 but this will result in higher levels of carbon monoxide in the exhaust stream as there will not be enough oxygen atoms to combine with all the carbon and CO readings will be elevated as seen by the 5 gas analyzer.
"immgunn" said it well in his earlier post. As fuel pumps weaken or air leaks occur the O2 sensor reads the amount of oxygen in the exhaust and is constantly trying to alter the fuel ratio to eliminate Hydro Carbons and NOX. This makes the EPA happy but weakens performance but only slightly.
Engineers spend a lot of time creating fuel maps but it is a compromise and their primary objective is to satisfy the EPA. After market tuners are more concerned with performance and want to provide a margin of error as well. Lean conditions are dangerous as they lead to higher combustion temperatures. After market tuners richen up the fuel maps and turn off the O2 sensor as they do not want the ECU to take control and try to achieve the 14.7 to 1 ratio again. This would ruin all the time they spent creating the fuel maps.
If anyone is interested JD Halderman has some great books on drivability and electronics.

 

[Guth_imp]

My family probably wouldn't be too thrilled with me if I were to start spending my nights at a Holiday Inn Express, but clearly it's been paying off for Toro.

Toro all joking aside, you're contributions to this thread are truly appreciated. I've got enough wrenches and such that I can get myself into plenty of trouble, but I don't have anything like the complex scan tools that you made mention of. In all honesty don't find working with electrical issues to be nearly as fascinating or as rewarding as I do simply working on the mechanical side of things. But I do like to be informed about what is happening with the inner workings of my bikes and that is where posts made by yourself and others come in so handy.

As I don't have the tools to take this any further, I'll update this thread after I've had a chance to get things looked at by the guys at my local shop.