Lambda parameters
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Joined: Dec 2006
Posts: 60
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From: Finland , 1995 LT-4 P-1SC
Lambda parameters
I have a Madtuner tuned PCM. Fast O2 Rich/Lean Threshold numbers are:
CL Mode 0 : 460 mV
16: 381 mV
32: 381 mV
48: 381 mV
64: 381 mV
Is these OK ? Which is a stock '94-95 PCM volts ?
If i change 460 mV ->450 mV examble , will the AFR goes to leaner at idle or richer ?
CL Mode 0 : 460 mV
16: 381 mV
32: 381 mV
48: 381 mV
64: 381 mV
Is these OK ? Which is a stock '94-95 PCM volts ?
If i change 460 mV ->450 mV examble , will the AFR goes to leaner at idle or richer ?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The O2 sensor response curve is extremely non-linear. The sensor basically acts more like a switch than anything else. It switches back and forth between rich and lean.
The ECM works with this input by making the injector pulse width larger if the O2 sensor is lean and making the injector pulse width smaller if the O2 sensor is rich. The mixture is never at the ideal AFR. It always is a LITTLE rich or a LITTLE lean and bounces back and forth between those two states.
The threshold is just that. Anything higher than that is considered rich by the ECM. Changing it from 450 mV to 460 mV would do nothing. Here's why:
The ECM works with this input by making the injector pulse width larger if the O2 sensor is lean and making the injector pulse width smaller if the O2 sensor is rich. The mixture is never at the ideal AFR. It always is a LITTLE rich or a LITTLE lean and bounces back and forth between those two states.
The threshold is just that. Anything higher than that is considered rich by the ECM. Changing it from 450 mV to 460 mV would do nothing. Here's why:
