| Author |
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Gemini
| | Posted on Friday, April 23, 2010 - 01:15 pm: | 
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in modern fuel injection systems there are a lot of variables that are taken into consideration for the fuel injection pulsewith(how much fuel is going into the motor. engine temp, rpm, tps, air temp are some of them. these are used to set the initial setting for pulsewith. they are then corrected/modified the output of the exhaust across the o2 sensors. that information is then used to modify the afv/ego, thus the name closed loop.
if you "fool" one sensor, in this case will we use the air temp sensor, and make it read higher than it actually is, the base injection will be lean, too little fuel. the o2 feedback would tell the ecm to richen(add more fuel). that richining is done through the afv(long term stored correction) or ego(short term correction). so with a air temp that is reading too high for actual temp, you will tend to see the afv or ego being higher than normal.
the opposite is true if the air temp sensor is being "fooled" into reading colder than it really is. sensor read too cold, base injection is alot of fuel, or sensor reads the exhaust as running rich(too much fuel) and the ecm leans(removes some fuel) by decreasing the avf or ego.
if you have the time, look through your eeprom using ecmspy or tunerpro. you will find that a sensor that is reading about 30F off, is "falsely" adjusting the fuel by about 4%. at 77f on my factory tuned bike, the air temp correction is 100%, at 99%f, the correction is 96%.
for those people who are concerned they are loosing power because the temp sensor is reading too high, don't worry, you got plenty of power and it is not running too rich or too lean because of the temp sensor. it will correct it's self due to closed loop.
for the people that are worried because the temp sensor display is not reading "true" outside temp, come on....there isn't anything more important to worry about?
i, myself, will keep the airbox in the factory design with the temp sensor in the stock location. i have learned that, for the most part, the temp display is about 10-11% higher than the "true" temp is out side. it doesn't bother me. i personally wished the cluster would default to gear indicator and coolant temp. but hey, i ain't that picky and it doesn't bother me that much.
i hope that wasn't too long of a read for most and that a few of you feel that you have a better understanding |
Mountainstorm
| | Posted on Friday, April 23, 2010 - 08:25 pm: |
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Thanks Gemini that made more sense than anything I have read on this subject here.
Can I ask do you think an Error Code for IATSYS might come up if the bike is doing too much correction because the IAT sensor has been relocated to a cooler reading location? I noticed that code after I was testing various locations.
Thanks! |
Ratsmc
| | Posted on Saturday, April 24, 2010 - 01:01 am: |
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Gemini,
Good information but it doesn't change the thinking that got me to where I am. In fact, it supports it.
1125s run lean. Reading 30 degrees hotter (according to what you just wrote) is going to make it run leaner. Whether that is dangerously lean or not is almost irrelevant - it is running lean.
And it is doing so based partly on a reading I was able to correct.
Was I worried about it before? Not worried but it bothered me. Why have a sensor if it is going to read wildly varying temperatures that were never actual?
Is it a fix for everyone. No. For Mountainstorm it made things worse. As with any mod, you need to consider the circumstances and your goals.
Putting on a super long swingarm because you think it is cool is really going to interfere with your canyon carving, right? don't do anything to your bike unless you understand what you are trying to accomplish and the ramifications it will have. |
Kicka666
| | Posted on Saturday, April 24, 2010 - 05:52 am: |
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Lock your AFV's, disable the closed loop junk, tune on the dyno.. your done.. |
Gemini
| | Posted on Saturday, April 24, 2010 - 06:53 am: |
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ratsmc, that is part at what i am getting at. 4% "misfueling" is pretty small. the o2 sensor is going to correct very quickly.
i think the more important thing, is the air temp sensor reading reflecting the actual air temp that is going into the motor? closed air box, you got one source of incoming air(barring any leaks or crankcase gases).
kicka666, i disagree with locking the afv and getting rid of the closed loop "junk". it is a great system that works much better than our congress. is has good checks and balances. is it perfect. no. no injection system is perfect. each system has different pros and cons. i have been working with speed density for about 10 years now, with a closed loop system, garbage in equals garbage out. with that said, a small exhaust leak near or before the o2 sensor is 100 times worse for a closed loop system that an air temp sensor that is a few degrees(even 30F+) because it got heat soaked from a radiator.
i understand closed loop and i like it. i know what the ecm wants and what it needs. i know how to tweak it to change the function if closed loop. stoich is 14.7. that is not the ratio for best fuel economy. you can run leaner and still be engine safe. 15.2-15.8 is more than safe. a poor idea to get that fuel ratio leaner is to try and fool a sensor. make the tps read lower or fool an air temp sensor and that closed loop crap is going to richen it back. the correct way to do that is to change the ecm wants.
there are good ways and bad ways, locking the afv is just as crappy as using an early powercommander.
quote
"Can I ask do you think an Error Code for IATSYS might come up if the bike is doing too much correction because the IAT sensor has been relocated to a cooler reading location? I noticed that code after I was testing various locations. "
the ecm only sets two fault codes refering to the inlet air temp sensor. one for voltage too high and one for voltage too low. there is not a correction limit exceeded fault. my guess would be the key was on when you unpluged the temp sensor one time
(Message edited by gemini on April 24, 2010) |
Kicka666
| | Posted on Saturday, April 24, 2010 - 08:53 am: |
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Each to there own Gemini, I have chosen to lock mine at 118 & disable the closed loop function & run my AFR's @ 13.5:1. 14.7 stoich is still lean, who wants fuel econ, I am lucky if I get 180kms from a tank, but all said your fuel differs greatly from ours in Aus. As for powercommanders they work very well on riceys & I have done alot of tuning with Jappos & commanders. Everyone has there own ideas for tuning, life would be pretty boring if we all thought the same.
Lest we forget. |
Mountainstorm
| | Posted on Saturday, April 24, 2010 - 09:04 am: |
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Thanks Gemini |
Captain_america
| | Posted on Saturday, April 24, 2010 - 07:30 pm: |
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Bottom line:
If I'm gonna be staring at that dam IAT reading to know what gear I'm in so I don't have to keep track in my head, That ^#%*%$ thing should be accurate!
Haha |
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