The Lambda Delete Thread

Clive

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I'm wondering why there is such a desire to get rid of the o2 sensor....
Closed loop control is by definition the preferable model for a fueling system and my industry experience tells me it should be retained BUT it is only as good as the algorithm which uses the data from it: If the fuelling map is being pulled around by the values from the o2 sensors then in the real world a constant input value may improve the rideability and an empirical approach wins since we have no control over the ECU programming and since we do not need to worry about the health of the cat in a decat system. The main loss will probably be, as you inferred, fuel economy.

PS no secondary sensor for Euro4.
 
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I thought the closed loop setting kept the mixture at a very lean, Euro 4 compliant setting.

All depends on the programming but it is likely that is what the lambda input is being used to keep a lean mixture, if the ECU was more open then the better solution was to get the lambda input to be used for a more user friendly result and a richer mixture. The resistor is a sticking plaster, if the ECU software continues to be closed then the better option is a new ECU with open access so users can write their own mixture/advance maps and target what mixture they want to achieve on closed loop.
 

iwilson

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I don't know what the target AFR is although it would be pretty easy to find out with a wideband sensor, but I'd be a little surprised if it made the kind of difference being discussed. My concern is that using a resistor with a fixed value may cause trouble. The ECU may read the value as too rich and lean out the mixture (there is a limit to how far it will go) or vise versa. A flat spot is more likely to be mapping related rather than the o2 sensor. Remember there are a whole load more factors than just the fueling going on, timing, cam profile, scavenging etc. Closed loop btw is not static the mixture is constantly swinging from slightly rich to slightly lean. There is no fixed value.

Can someone confirm that unplugging the sensor actually produces an error? I remember asking Norton the question when I fitted my megaphones and was told although o2 sensors are not used on the factory megaphones they were not turned off in the ECU even when loaded with the megaphone map. My bike has the megaphone map and my o2 sensors work. If there's no fault light and the ECU doesn't throw a wobbly and load a get you home map you may just need to pull the o2 sensor plugs and the ECU will just use its own maps for fueling which is I think what some want.
 
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Just taken the bike out for a spin having removed the lambda sensors... it's now running extremely well with none of the hunting that plagued the bike at very low revs! It's now really great to ride!

Fantastic news!!! And you used these plugs right? Only thing you did differently was resistor plugs??
 
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I have also just removed my lamda sensors and fitted resistor plugs although only ridden for about eighty miles to check difference. No warning lights, no appreciable difference in performance but appears to be much better at low speed riding (ie in town traffic). I am not that expert in the mechanics it but seems better. If this did not work out, I was going to use it as a prelude to getting a PC fitted, Moto Corsa was sorting it out but seem to have lost interest and have not replied to my emails. This may save me £500 if it proves successful, heres hoping
 

iwilson

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The upshot of that appeared to be unless you fit a pretty sophisticated simulator you're just going to end up maxing out the fuel trim in one direction or the other. If there's no engine light then I would just remove the o2 sensor and NOT replace it with a resistor.

I have also just removed my lamda sensors and fitted resistor plugs although only ridden for about eighty miles to check difference. No warning lights, no appreciable difference in performance but appears to be much better at low speed riding (ie in town traffic). I am not that expert in the mechanics it but seems better. If this did not work out, I was going to use it as a prelude to getting a PC fitted, Moto Corsa was sorting it out but seem to have lost interest and have not replied to my emails. This may save me £500 if it proves successful, heres hoping
Again I would suggest just unplugging the o2 sensors electrical plugs if no engine light then the ECU will just be running in permanent open loop. By using the resistor it may be running at the extremes of the fuel trims.
 
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Only one way to find out : measuring the AFR with a broadband lambda with the resistor plugs installed !
 

Clive

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Only one way to find out : measuring the AFR with a broadband lambda with the resistor plugs installed !
You can buy gauges used in motorsports to connect to lambda sensors and give an AFR readout. For our porpoises a simple regulated voltage out and multimeter on the output would probably do to indicate variation. Put it to the back of the projects list...
 
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Wow what a can of wriggly worms this has turned out to be. You guys seem to have a wealth of info, I think in the meantime I will ride some more then check the condition of the spark plugs - perhaps they may show if the fuelling is way out. :confused:
 
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best way to check that fueling, is to go ride, till everything is nicely up to temperature, and then stop the engine after a good blast, asap !!! Not letting the revs drop, or letting the bike idle !! Just cut the ignition, and stop the bike. Pull the plugs, they should be "café au lait" !
 
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best way to check that fueling, is to go ride, till everything is nicely up to temperature, and then stop the engine after a good blast, asap !!! Not letting the revs drop, or letting the bike idle !! Just cut the ignition, and stop the bike. Pull the plugs, they should be "café au lait" !
Great advice will do and let you know, cheers
 

nopdog

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What's the deal on the plugs!! They are way too big when removing the sensors.
The plugs that screw into the header pipes when the sensors are removed are way to big. Or am I missing something.
I do recall that someone asked what was the size of the blanking plug but can't find it.
Help
 
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What's the deal on the plugs!! They are way too big when removing the sensors.
The plugs that screw into the header pipes when the sensors are removed are way to big. Or am I missing something.
I do recall that someone asked what was the size of the blanking plug but can't find it.
Help
I’m installing mine in the next hour. I made the same Mistake and got the kit with the threaded plugs too. Someone on here found some SS button head bolts. Thats what I’ll do to.
 

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