No. it will only run closed loop in the AFR range of the narrow band sensors (14.3-15.2). outside of that range it will run open loop.

 

Hi,

I notice if i give it throttle quickly the "set afr" will change even if bike set for closed loop at a particular MAP and RPM, then afr goes back to closed loop reading of 14.6 when lay off throttle

Thanks
Mirrmu

 

That would probably be AE, I decreased my Acceleration Enrichment when I richend up my AFR table, It was getting a lot more with it set to enrich the mostly closed loop AFR tune I started with.

 

Hi,

Thanks i check it out in winpv

Mirrmu

 

In the PV the software is set up so that a setting of 14.6 works as a switch to refer the mix to the closed loop bias table. The CLB when set at 450mv will result in a 14.6 stoich value, but when set higher, like 700 or 750 you will get a 12.8 mixture.

PS I'm not an expert, but I am pretty sure on this and wonder if this is why you are seeing this jump to the rich mix. What is confusing when reading your AFR table when looking at it in WinPV in looks like it is set to 14.6.

 

Set AFR & Set Lambda are channels which are reported based on desired AF/Lambda +/- any multipliers such as acc enrichement, decel enleanment, or warmup enrichment

 

You can only change the closed loop operating range within the effective range of the O2 sensor itself. This is approx 14.3-15.0 AFR, nbO2 sensor output is non linear so for example once O2 voltage is above say 800mv it does not know the difference between 14.1 and 12.0 AF. A short answer is if you open up the O2 range the ECM will chase its tail looking for the requested O2 voltage and in the end will not be able to delivery the correct fuel mixture.


Here is a chart which references O2 voltage vs. AFR (assuming 14.7 stoich). Note the non linear output of the sensor, specifically what happens to voltage below 14.2 and above 15.0

 

Thanks Jamie, that graph is really helpful. That seems to invalidate oldhippie's assertion that a CLB setting of 700 or 750 will result in an AFR of 12.8. Certainly the PV wouldn't allow you to set up a bias in closed loop that forces the AFR that far outside of the O2 sensors operational range. I've seen it stated that we should use 700-750 for CLB, but where on the O2 voltage curve (what AFR) would CLB=750 fall?

 

I have gotten my speedo working now and would like to Start finding some more performance from this boat...

How long should an auto tune session be?

Can bike be cut off and restarted during an auto tune session?
I like to stop for a cold beer often.

How will I know when I done enough auto tuning???

I've read that once changes are less than 5% you are done.

But how do you know what the changes are???

Someone told me to work on the VEs first.
I have no idea what they are.
Are how to go about this.

I have read all I can find about the PV and have no more understanding of it than the man in the moon...

Thanks for any help.

 

Bias voltage is the specific voltage the ECM refers to when in closed loop, it's actually pretty simple, say your O2 bias is 450mv; all the ECM really knows is above this voltage is rich, below this voltage it is lean. When looking for the rich side of closed loop we do not generally go higher than 700-750mv, remember the ECM modulates the injector signal/AF over the O2 bias voltage, the mixture is varied rich/lean/rich/lean.. very quickly over this "switching" voltage. The ECM uses a specific PID, and as it modulates if you get to the edge of the curve with the sensor swing it may be outside of its curve.

It's also important to note that most newer bikes do not use Bias tables, closed loop control is based directly off the main Lambda table. This is much better as Lambda is absolute regardless of fuel, where AFR is based on stoich of the specific fuel (measured Lambda X stoich value =AFR) EX: .89 X 14.68 = 13.06 AFR. Hope this info helps