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Hooked my car up to a computer to get a look at some live data and how and my engine is running took a few photos while not sure what some of the stuff is can anyone take a look let me know what you think
#14
#17
#19
#7
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#12
I don't know what these number are supposed to me but if some can shed some light it would be appreciated
even with no codes short term fuel trim and long term fuel trim are generally what I look at first for engine driveability / wellness
fuel trim is compensation the computer is doing to run as close to o.e. spec as possible.
the voltage indicated on the bank 1 sensor 1 and bank 2 sensor 1 oxygen sensors is what the ecu is looking to find necessary adjustments. but note that because stock o2 sensors are not wide band the voltage will constantly cycle and will not update fast enough for accurate display.
sensor 1 is precat. sensor 2 is post cat aka downstream and should be cleaner to indicate the cat is doing its job.
a general rule of thumb for most obd2 cars is +/- 10% is acceptable. at +/- 15-20% you may start to see lean codes / rich codes and this is indication there is heavy compensation being done. + 20% you probably have a real problem like weak fuel pump -20% something is throwing off the fuel.
long term trim is as it implies what is happening over a long period of time (trend). short term is the constant fine trimming being done due to differences in rpm, temp, load, atmospheric conditions etc. this is separate to long term. i.e. 5% long + 5% short is +10% correction.
when you clear codes or disconnect battery the long term should reset, but will adjust again over time.
even with no codes short term fuel trim and long term fuel trim are generally what I look at first for engine driveability / wellness
fuel trim is compensation the computer is doing to run as close to o.e. spec as possible.
the voltage indicated on the bank 1 sensor 1 and bank 2 sensor 1 oxygen sensors is what the ecu is looking to find necessary adjustments. but note that because stock o2 sensors are not wide band the voltage will constantly cycle and will not update fast enough for accurate display.
sensor 1 is precat. sensor 2 is post cat aka downstream and should be cleaner to indicate the cat is doing its job.
a general rule of thumb for most obd2 cars is +/- 10% is acceptable. at +/- 15-20% you may start to see lean codes / rich codes and this is indication there is heavy compensation being done. + 20% you probably have a real problem like weak fuel pump -20% something is throwing off the fuel.
long term trim is as it implies what is happening over a long period of time (trend). short term is the constant fine trimming being done due to differences in rpm, temp, load, atmospheric conditions etc. this is separate to long term. i.e. 5% long + 5% short is +10% correction.
when you clear codes or disconnect battery the long term should reset, but will adjust again over time.
07-04-2019, 07:56 PM
