View Full Version : Tuning NB 02 lean for smog test (mot uk)
Gelf VXR
October 9th, 2009, 07:28 PM
I'm sure I've read this being done on here but cannot find the post?
If I wanted to program the psuedu NB output of an LC-1 to switch slightly leaner than stoich.
At my last test I had tailpipe lambda 1.006 (limits 0.97-1.03)
From the programmer text
1.1V = 0.958 lambda (richer than stoich)
0.103 = 1.022 lambda (leaner than stoich)
0.97V = 0.064 difference between upper and lower limit
0.064V = 0.01 lambda
If I program the LC-1 as below would this work?
1.036V = 0.958
0.039V = 1.022
mr.prick
October 10th, 2009, 03:54 AM
Why not just change the commanded AFR.
Gelf VXR
October 10th, 2009, 04:11 AM
It will be in closed loop for the emmisions test
mr.prick
October 10th, 2009, 04:19 AM
I mean change {B3601} Ratio of Air to Fuel for Stoichiometry.
Your OS may have a different parameter number.
This will change the CL and PE commanded AFRs.
Gelf VXR
October 10th, 2009, 05:06 AM
My os does not have any calibrations of that type
thanks thou
gmh308
October 10th, 2009, 09:57 AM
My os does not have any calibrations of that type
thanks thou
Which OS do you have?
joecar
October 10th, 2009, 05:03 PM
Can you program the NBO2 switch points in the PCM calibration...?
If you do get it leaner, watch out that NOx levels increase (as you go leaner)... are the smog authorities measuring NOx levels...?
Gelf VXR
October 11th, 2009, 06:34 PM
The only table for idle airflow is {B1829} minimum desired airflow per gear.
My OS is 02596734
Gelf VXR
October 11th, 2009, 06:43 PM
Can you program the NBO2 switch points in the PCM calibration...?
If you do get it leaner, watch out that NOx levels increase (as you go leaner)... are the smog authorities measuring NOx levels...?
I don't think so, the results of my previous emmisions test, it does not list NOx
Natural idle
engine speed 450 to1500 rpm manual check pass
CO =< 0.30% 0.3% pass
Fast idle test
engine speed 2500 to 3000 rpm manual check pass
CO =< 0.2% 0.12% pass
HC =< 200 ppm 14 ppm pass
Lambda .97 to 0.93 1.006 pass
I have aded the attachment image that shows the effects of AFR on the various emmisions
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