How does the ECM work to calculate fuel trim?
To better understand how fuel trim numbers are generated, the ECM/PCM uses the oxygen sensor or air/fuel sensor input signal to adjust fuel injector pulse-width values. If a longer-than-normal injector pulse width is required to maintain the desired oxygen sensor signal, the ECM/PCM displays an increased fuel trim value in its datastream.
How does the post catalyst fuel trim system work?
The PCM keeps track of the fuel mixture ratio through oxygen sensors in the exhaust system that measure the amount of oxygen burned by the engine. There is an oxygen sensor positioned before and after the catalytic converter. One oxygen sensor, which is referred to as the upstream sensor, sits between the engine and converter.
Is the oxygen sensor accurate for fuel trim?
Of course, accurate fuel trim values are based on a properly functioning oxygen sensor. So, when diagnosing any fuel injection malfunction, it’s important to make sure that the oxygen sensor is accurate and responsive to fuel trim changes.
How does short term fuel trim ( STFT ) work?
Short Term Fuel Trim (STFT) Short-term fuel trims occur as a direct result of changes in the oxygen content of the exhaust stream. The exhaust stream is monitored by an oxygen sensor upstream of the catalytic converter, and the signal voltage it generates is directly proportional to the oxygen content of the exhaust stream.
How does the downstream fuel trim system work?
The downstream O2 sensor is considered to be protected from extreme environments by the catalyst. The Powertrain Control Module monitors the downstream O2 sensor feedback control, called downstream fuel trim, to detect any shift in the upstream O2 sensor target voltage from nominal target voltage.
The PCM keeps track of the fuel mixture ratio through oxygen sensors in the exhaust system that measure the amount of oxygen burned by the engine. There is an oxygen sensor positioned before and after the catalytic converter. One oxygen sensor, which is referred to as the upstream sensor, sits between the engine and converter.
To better understand how fuel trim numbers are generated, the ECM/PCM uses the oxygen sensor or air/fuel sensor input signal to adjust fuel injector pulse-width values. If a longer-than-normal injector pulse width is required to maintain the desired oxygen sensor signal, the ECM/PCM displays an increased fuel trim value in its datastream.
When does Bank 2 oxygen sensor 2 report a lean condition?
When the bank 2 oxygen sensor 2 unit reports a lean condition in the exhaust stream leaving the converter, the engine’s computer stores a code P2098. The catalytic converter helps control your car’s emission levels by breaking down noxious gases into less harmful pollutants before they leave your exhaust.