Desired AFR - Actual AFR

[Steve Cole]

The changing fuel has everything to do with the problem. Years ago when the fuel was the same everywhere it was much simpler. Let's understand that ANY O2 sensor does not care about AFR at all. It's only job in life is to measure the O2 level in the exhaust and compare it to the O2 level outside the exhaust. From those two readings it generates a voltage, that's it. From the O2 level lots of things can be inferred, IF, and its a big IF you know all the other information. When you do not have all the other information you can and will make wrong assumptions!

Fuel today is anything but the same and since we do not know what fuel is being run at any one moment in time Air Fuel Ratio is a problem and that is just why the rest of the engine companies switch to terms of Lambda years ago. HD is just now coming around to it and most of the aftermarket still doesn't understand it. In order for a meter to read in AFR it has to ASSUME some number for the fuel to do the conversion from O2 level to AFR. IF you do not know the assumed value in the meter and the real value of the fuel being used, the readings are incorrect. How far off they are depends on the assumed value versus the real value of the fuel. So if you purchase an AFR meter, what is it calibrated too has to be a big question because if it's not the fuel you run all the displayed values are wrong.

With Lambda measurements it just comes direct from the O2 sensor. A lambda of 1 is the perfect burn ratio for any fuel and if the value is less than 1 its richer, greater than 1 its leaner. Very straight forward and the fuel variations now are gone. From Lambda we can convert to AFR values as long as we know the Stoichometric value for the fuel you are using. As with all systems there are limits to how far it can measure but as long as you stay in it range it works perfect. If you need more range then get a different system that is designed to properly run in the range you are looking for.

[wolf_59]

The changing fuel has everything to do with the problem. Years ago when the fuel was the same everywhere it was much simpler. Let's understand that ANY O2 sensor does not care about AFR at all. It's only job in life is to measure the O2 level in the exhaust and compare it to the O2 level outside the exhaust. From those two readings it generates a voltage, that's it. From the O2 level lots of things can be inferred, IF, and its a big IF you know all the other information. When you do not have all the other information you can and will make wrong assumptions!

Fuel today is anything but the same and since we do not know what fuel is being run at any one moment in time Air Fuel Ratio is a problem and that is just why the rest of the engine companies switch to terms of Lambda years ago. HD is just now coming around to it and most of the aftermarket still doesn't understand it. In order for a meter to read in AFR it has to ASSUME some number for the fuel to do the conversion from O2 level to AFR. IF you do not know the assumed value in the meter and the real value of the fuel being used, the readings are incorrect. How far off they are depends on the assumed value versus the real value of the fuel. So if you purchase an AFR meter, what is it calibrated too has to be a big question because if it's not the fuel you run all the displayed values are wrong.
With Lambda measurements it just comes direct from the O2 sensor. A lambda of 1 is the perfect burn ratio for any fuel and if the value is less than 1 its richer, greater than 1 its leaner. Very straight forward and the fuel variations now are gone. From Lambda we can convert to AFR values as long as we know the Stoichometric value for the fuel you are using. As with all systems there are limits to how far it can measure but as long as you stay in it range it works perfect. If you need more range then get a different system that is designed to properly run in the range you are looking for.

Thanks Steve
This is the answers to the questions that I was looking for and to what I was thinking just didn't know how to word it properly

[rbabos]

This might be off subject, but why is there a CLB setting for 100 KPA? If you cannot run closed loop there why is it there? And does that setting have a big effect on actual fuel values?

Hell, my clbs only go to 80kpa, but the afr map can be set to 14.6 at 90kpa with no clb. 100kpa is strickly open loop only.
Ron

[Steve Cole]

This might be off subject, but why is there a CLB setting for 100 KPA? If you cannot run closed loop there why is it there? And does that setting have a big effect on actual fuel values?

Hell, my clbs only go to 80kpa, but the afr map can be set to 14.6 at 90kpa with no clb. 100kpa is strickly open loop only.
Ron

This is the Harley world were working in so this applies here but may not elsewhere. The last value you see is used any time you exceed it so if you set a CLB at say 80 kPa it will use that (if told too) all the way to the end of the range of the sensor. There are many other things that setup the range something is allowed to work in that is not included in any tuner out today and if you do not know where and what they are set for its hard to say where the limits might be based off of looking at one table. Just because it's there doesn't mean it's being used by the ECM at all.

[strokerjlk]

       Actually 450mv is 14.68, so you are both wrong.



Ron

and there you have your answer to tuning with your new T/S .
if you want to develop a closed loop map  set the CLB to 450 mv and dial the ve's in.
you only set the closed loop portion you want to run. the rest of the map you dial the open loop in to the AFR you want to run there.

if you want to dial your open loop tune in with T/S, dial the map in to your current AFR table.