I have a '11 TE-449 with the resister installed and that leaves the O2 sensor unplugged. If the O2 sensor isn't giving the ECU inputs, how does the ECU compensate when I go up in altitude? Does the bike have a MAP(manifold air pressure) sensor? If it does, does it give input to the bike while running or wait to get a value when you turn the key on? Meaning, if I go up in altitude, will I have to periodically kill my bike and restart it to get the fueling to adjust?
Well, most sensors operate on resistance so I'd assume they operate all the time, like the throttle position sensor. I'm not guaranteeing or claiming to know about whether this is the case withe MAP sensor but I have trouble believing it just takes one reading then goes to sleep.
Altitude change from 1500 to 8000 feet makes my idle speed drop 1850 to 1600. Have to dial in more air/idol speed.
So, if the throttle body has a sensor that measures air density, like it has been claimed the bike has, I wonder why wouldn't the ECU adjust for the thinner air and make the adjustment itself? Also, if the ECU knows when the bike is cold (temp sensor) does it enrich the fuel mix automatically, then why is there a fuel enrichment knob on the throttle body?
My experience Has been this at 8000 ft v. Sea level. Idle is 1500-1600 initially at 8000 ft. I have ridden it this way several different trips up here. After riding for an hour or so, it seems to idle around it's normal 1850-1950. Yesterday I set the idle up to 1850 after a 3 min. Warmup and went for a ride. Returning I noticed the idle was over 2000-2100. Not quite sure what is happening but this is fairly consistent and noticed the lower idle on my 2008 TE250 also.
The O2 sensor is not a wide band and can only adjust a little (ie. +/- 10*f and 2-3,000'). If you started at seal level and rode up to 10,000' it would not adjust enough. When the o2 is removed and the resistor is in placed, the air/fuel setting is preset and will not change. I rode to a party a couple of years ago in 60*f weather and all seem fine. The short drive back at night was in the 30's*f and it was popping, running very lean. 2008 TE250 w/PU
This is precisely what I think as well. Where do you get the data to make this statement? Is there some Mikuni information that we can get to somewhere?
Next time I ride up to altitude rather than transport I'll see what the idle speed is when I get there. See if it can adjust itself.
The 449 doesn't actually use a resistor like the 250/310 but just a loop of wire. When this is installed the ECU completely ignores the lambda whether it's fitted or not. The bike has sensors for air pressure, air temperature and engine temperature in addition to throttle position and to my knowledge continues to adjust the fuelling based on the inputs from these sensors. So in theory the bike will continue to fuel correctly at any given altitude or temperature. The idle speed is determined primarily by a manual air bypass screw rather than electronic control so the bike can't adjust this, although 449 does havre the ability to lift the idle slightly moving the throttle stop. Dave
I had a long talk with several well known dealers and this is how it was described. Also based on my experience with 2008 TE250/2010 TE310 once o2 sensor is removed, the colder it gets the leaner the bike runs. Give JD tuner a call and he will help you out with the system. Once the o2 is removed the "race map" fueling is set and doesn't change. If the sensors (fuel related) send info to the ECU, it falls on deaf ears. Outside the way the fuel is delivered, it's a carb at this point. I don't have experience with the 450/511 but was told they work near the same as the small bores.
This seems at odds with "cold engine needs fuel enrichment", could you elaborate on why the ECU would be leaning out the mixture when it is getting a reading of COLD from the temp sensor? I agree with the "electronic carb" position, that there is no real-time adjustment of fuel delivery based on environment.
ECU is not leaning out the mixture rather it is not adjusting from a spot on 75*f settings. At 30*f the motor was lean telling me once o2 is removed the fuel map is non-adjusting. How would it know where to adjust if the fuel/air input is not there?? If your carb was jetted a 75*f and you rode in the snow, what would happen??
The loop of wire acts as a resistor or a ground (like on other bikes) I assuming. If this wire disables the o2 (lamba) sensor, how does the ECU know which way to fuel without the nose (lamba sensor) sniffing?? Even with the other sensors end adjustment would be based on how much fuel is left in the header. Years ago in the snowmobile arena there was altitude compensators sold aftermarket that used a material that changed orfice size. This was placed inline on the vent lines from the carb. Work as design however when on a long up hill pull the sled would get stuck. By the time it was unstuck, started again the motor leaned out because the heat under the hood made it seem like it was a hot day. This would be the same if the ECU adjusted based on the other sensors and not using O2 readings. This assuming, is why the fuling is locked when the O2 sensor is disabled.
I'm even more confused now. I looked at my O2 sensor and it is just unplugged. I can see no loop of wire plugged into the connector. When I start the bike it says Race Map II though. Where is this loop of wire supposed to go on the 449?
Sorry but I don't believe this to be correct. If the ECU is not using the sensor values then a faulty sensor would not cause a running problem but they do. My understanding is that race mode provides a inherently richer base map and the ECU adjusts fuelling as required to match air pressure / air temperature / water temperature using this richer base map as the reference point. Dave
The loop of wire is plugged in under the seat. It's a small 2 wire plug normally tucked in next to the diagnostic plug. Its only on the Mikuni systems that a resistor plugs into the lambda socket on the loom. Dave
Nothing unless you take the plug/loop out. The ECU ignores the lambda with the plug in, take the plug out and you'll be back to 'limited' power but the ECU will use the lambda to fine tune the fuelling for emissions rather than performance. Dave
