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Checking for Closed loop mode on idle


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My car failed local emissions test, Below is the info on the report


Oil temp: 82c


Low idle(760rpm)

CO 0.02 vol%

HC 13 ppm


High idle(2850 rpm)

Lambda 1.02

CO 0.51 vol% and it needed to be below .2%

HC 47 ppm



I asked my tuner if he thought the tune might be a bit rich, he asked to check and make sure its running in closed loop mode on low load and idle.


When i checked with romraider the only parameter is saw was cl/ol fueling and that ranged from 7 to 10 while revving to about 3000rpm


What parameters should i log go see if im running rich?

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14.7 is what the ECU is targeting for closed loop AFR at idle. If you are seeing 14.7, you are not running rich. I'm not sure if the car can run at stoich mixture in open loop, but if you also log the CL/OL fueling as described above that will tell you.


BTW, lambda (from your emission report) is the ratio of AFR to stoich (14.7). Since you are 1.02, you are very close to 14.7 AFR at the high idle.


How modified is your car? Do you have catted or catless DP?

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I have 3" catless DP with sports cat cell in lower center section, it passed 2 years ago, maybe cell is done and needs to be replaced. I'll price up a replacement for this, might be the cheapest route!
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