closed loop system?
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Joined: Oct 2007
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From: New England
When you try to digest the entire concept of fuel injection and electronic ignition at once, it does appear very confusing.
It's really not too bad once you learn the very basics and build from there.
Good luck!
It's really not too bad once you learn the very basics and build from there.
Good luck!
If you look at the thumbnail picture of the AFR (Air Fuel Ratio) tables that was posted by jluvs2ride you'll see on the left side it has the RPM ranges and across the top it has MAP kpa, the RPM ranges are pretty much self explanatory but the MAP ranges are basically the load that is being put on the bike, throttle position, weight on the bike, road grade etc. are some of the things that effect the MAP load. At cruising (55 - 60 MPH) your bike will be in the 40% MAP range at about 2300 RMP's or so, the stock set up is pretty lean (14.7:1 air fuel) to meet EPA standards. If we leave this area of the MAP alone your o2 sensors will make minor adjustments to try to acheive the 14.7:1 a/f. That is closed loop. If you look at the thumbnail again all the red areas are were the bike will be in closed loop. Now if you are cruising 55 MPH and want to pass someone or just get on it, your RPM's will obviously start to go up, the MAP load will go up as well, under hard acceleration it'll get up to 80 and 100%, this is where the bike goes out of closed loop and into open loop. If your bike is set up to run 13.0:1 A/F in high MAP loads that means that it is running richer (more fuel), but since the o2 sensors aren't turned on at this point the bike is relying soley on the tune, when we tune a bike we are basically calibrating it to a known constant. We make passes on the dyno and record the throttle position and the RPM ranges for a throttle position and the A/F that the bke is actually running. Then we "teach" the ECM on the bike what the A/F is actually doing. In a nutshell that is how we tune A/F If we lower the red cells to turn off the o2 sensors (closed loop) the bike is running completely on the tune.
Elite HDF Member
Joined: Apr 2008
Posts: 4,718
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From: Back in the Good Ole USA. South Carolina to be exact.
It is really not that confusing but you'll have to put some effort into learning.
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Cruiser
Joined: Dec 2010
Posts: 184
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From: Southeastern NC
If you look at the thumbnail picture of the AFR (Air Fuel Ratio) tables that was posted by jluvs2ride you'll see on the left side it has the RPM ranges and across the top it has MAP kpa, the RPM ranges are pretty much self explanatory but the MAP ranges are basically the load that is being put on the bike, throttle position, weight on the bike, road grade etc. are some of the things that effect the MAP load. At cruising (55 - 60 MPH) your bike will be in the 40% MAP range at about 2300 RMP's or so, the stock set up is pretty lean (14.7:1 air fuel) to meet EPA standards. If we leave this area of the MAP alone your o2 sensors will make minor adjustments to try to acheive the 14.7:1 a/f. That is closed loop. If you look at the thumbnail again all the red areas are were the bike will be in closed loop. Now if you are cruising 55 MPH and want to pass someone or just get on it, your RPM's will obviously start to go up, the MAP load will go up as well, under hard acceleration it'll get up to 80 and 100%, this is where the bike goes out of closed loop and into open loop. If your bike is set up to run 13.0:1 A/F in high MAP loads that means that it is running richer (more fuel), but since the o2 sensors aren't turned on at this point the bike is relying soley on the tune, when we tune a bike we are basically calibrating it to a known constant. We make passes on the dyno and record the throttle position and the RPM ranges for a throttle position and the A/F that the bke is actually running. Then we "teach" the ECM on the bike what the A/F is actually doing. In a nutshell that is how we tune A/F If we lower the red cells to turn off the o2 sensors (closed loop) the bike is running completely on the tune.
You bet. I like it when the light bulb turns on in someones head. Feel free to PM me if you have any questions. I'll help in anyway i can.
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