Lambse.. Explain

[04 Mach1]

My Lambse at idle are around 13.8 to 14.2 if I crack the throttle and hold to 2000 rpms it goes up to 16.8 to 18.1 car starts and idles fine but headers glow. Today I leaned the maf curve 6% ended up with lambse at idle 10.7 to 12.8 at 2000 rpms they sit at 14.67 to 15.3 headers still glow, fuel adaptive are set back to stock setting, oh this is with a 90mm lightning maf.

[QWKSNKE]

but they are only glowing at 2k rpm, right? At idle they are no longer glowing, correct?

[04 Mach1]

correct at idle its a ok its, just when you crack the throttle alittle

[Cougar5.0]

Yeah, that leaning out at tip-in drove me crazy. Look at the commanded LAMBSE in the datalog below:



I ended up forcing the ECU to go open loop sooner to stop the lean bog. I'd love to know the real reason for this behavior. Adjusting the MAF a dozen times did nothing except change whether the KAMRF's were above or below 1. For a moment I thought EGR - except mine is turned off. There is an answer to this - I just don't know what it is yet...

[93Cobra#2771]

Originally Posted by sailorbob

This is not strictly correct, it's possible to set the closed loop AF ratio from anywhere between 29.28:1 and virtually 0:1 if you know where to look in the code.

Expand, please.

Also, how would the EEC be able to maintain the reset a/f correctly? Factory narrow bands couldn't monitor that. It would basically end up as an OL system, right? Or perhaps some type of custom O2, that would be made to target that a/f and allow switching?

Not bashing, just curious how this would be advantageous for someone to change.

Of course, if you ran a wideband O2 and kept close watch, I suppose you could at least make sure you aren't hurting anything, and that your commanded a/f is on the money. But adaptive would certainly be out, and it seems to me that running in CL would be out.

[Dale McPeters]

Originally Posted by 93Cobra#2771

Expand, please.

Also, how would the EEC be able to maintain the reset a/f correctly? Factory narrow bands couldn't monitor that. It would basically end up as an OL system, right? Or perhaps some type of custom O2, that would be made to target that a/f and allow switching?

Not bashing, just curious how this would be advantageous for someone to change.

Of course, if you ran a wideband O2 and kept close watch, I suppose you could at least make sure you aren't hurting anything, and that your commanded a/f is on the money. But adaptive would certainly be out, and it seems to me that running in CL would be out.

You are correct Richard the standard narrow band sensor would be worthless
if the code were changed to do this, it would not be able to adjust in the
range required.
However it would be great for open loop type tuning using a true WB O2 sensor.

[sailorbob]

You're right about needing to change the lambda sensor for a wideband that could run from 10:1 to say straight air (the 29.82:1 is a software limitation).

The software side of things gets more complicated with two things required, firstly where ever the eec is setting for stoichiometric then you need to adjust this for your new desired AF ratio (as an aside, Ford do this on my turbo ecu for some of the self tests and run a AF ratio of 13.97:1 instead of the 14.64:1 I've seen on normally aspirated ecu's and the software must do some adaptive learing inhibiting to maintain it). The second software change is to cope with the different output from the wideband either by rescaling for the wider voltage or adjusting for a simulated narrow band output and accepting for the loss of resolution.

I'm not saying this is particulary easy but it could be done. Dale, I recall reading somewhere a long time ago about someone who rewrote part of the A9L code to use a wideband sensor through the egr input which I guess was for open loop tuning.

[93Cobra#2771]

Very good - I figured that was what you meant, just wanted to make sure...

[Dale McPeters]

Originally Posted by sailorbob

I'm not saying this is particulary easy but it could be done. Dale, I recall reading somewhere a long time ago about someone who rewrote part of the A9L code to use a wideband sensor through the egr input which I guess was for open loop tuning.

You would be correct.