Understanding AFR: Calibrating Your Wideband
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Calibrating Your Wideband
02.51
| 00:00 | Getting accurate results from most wideband controllers requires proper free air calibration. |
| 00:06 | This needs to be done away from any potential exhaust fumes or the reading can be compromised. |
| 00:12 | While some wideband manufacturers suggest that this calibration process can be completed with the sensor still fitted to the exhaust, my personal preference is always to remove the sensor and do it in proper clean air. |
| 00:28 | If you are sending the signal from a wideband controller into an ECU, its also essential to confirm the reading you are seeing on your laptop is accurate. |
| 00:39 | When we have a digital AFR or lambda number displayed on our laptop screen, its easy to believe it. |
| 00:47 | Unfortunately its also possible for this reading to be completely inaccurate so we need to check before we start tuning. |
| 00:55 | There are two possible reasons why your laptop may show the wrong reading. |
| 01:00 | The first, which should be pretty straightforward, would be to have the wrong calibration data in the ECU. |
| 01:07 | Your wideband will come with instructions telling you what voltage output equates to what AFR or lambda value. |
| 01:14 | Normally this is done at two points such as 0 volts and 5 volts. |
| 01:19 | It goes without saying that entering the calibration data correctly should be your first step. |
| 01:26 | Even with the right data entered, you still may have a reading that is slightly inaccurate. |
| 01:33 | The reason for this is that the AFR data is transmitted by an analogue voltage that typically varies between 0 and 5 volts. |
| 01:41 | The reading is therefore very sensitive to the accuracy of this voltage, and ground offsets and even voltage drop through long wiring can effect the voltage the ECU receives. |
| 01:55 | An easy way to check this is to configure the wideband controller to output a fixed voltage of say 2.5 volts. |
| 02:04 | You can then see what voltage the ECU is receiving and confirm the two are the same. |
| 02:10 | If you have a minor voltage offset here, you can correct the calibration points to account for this. |
| 02:18 | Obviously if you are using the output from a wideband with a display, it is also a simple matter to make sure that the output on the laptop matches what the wideband is showing on its display. |
| 02:32 | I can’t stress enough how important it is to take the time here to make sure the wideband is set up and calibrated correctly. |
| 02:42 | If you can’t rely on the accuracy of the AFR display, you could risk doing serious damage to your engine. |
