AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 125)

Page 125 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Lambda to AFR conversion chart
Lambda AFR Lambda AFR Lambda AFR Lambda AFR
1.3 19.03 1.14 16.69 0.98 14.35 0.82 12.00
1.29 18.89 1.13 16.54 0.97 14.20 0.81 11.86
1.28 18.74 1.12 16.40 0.96 14.05 0.8 11.71
1.27 18.59 1.11 16.25 0.95 13.91 0.79 11.57
1.26 18.45 1.1 16.10 0.94 13.76 0.78 11.42
1.25 18.30 1.09 15.96 0.93 13.62 0.77 11.27
1.24 18.15 1.08 15.81 0.92 13.47 0.76 11.13
1.23 18.01 1.07 15.66 0.91 13.32 0.75 10.98
1.22 17.86 1.06 15.52 0.9 13.18 0.74 10.83
1.21 17.71 1.05 15.37 0.89 13.03 0.73 10.69
1.2 17.57 1.04 15.23 0.88 12.88 0.72 10.54
1.19 17.42 1.03 15.08 0.87 12.74 0.71 10.39
1.18 17.28 1.02 14.93 0.86 12.59 0.7 10.25
1.17 17.13 1.01 14.79 0.85 12.44 0.69 10.10
1.16 16.98 1 14.64 0.84 12.30 0.68 9.96
1.15 16.84 0.99 14.49 0.83 12.15 0.67 9.81
Knock Sensor
The knock sensor is like a microphone mounted to the engine block that is used to detect
combustion knock. Every engine is different with respect to the amount of noise it generates. In
most production engines, the sensitivity of the knock sensor is based on an average noise
profile generated during dyno testing. A knock sensor that has a slightly lower threshold of
sensitivity to knock is used to compensate for variances in engine noise. When the engine
makes noise in frequencies and amplitude higher than the baseline noise profile, the sensor
senses knock and the ECU reduces ignition timing until the noise (knock) is suppressed.
Engines that have knock sensors on them from the factory need to have the baseline noise
profile recorded when setting up the AEM EMS.