04) Petrol 2 speed idle emission test
04.1) Test Stage 1
04.2) Test Stage 2
04.3) Test Stage 3
04.4) Outside testing limits
04.5) Petrol 2 speed idle emission test with OBD compliant vehicle
4.4) Outside testing limits
When the emission values are outside of 'legal' parameters the ‘bad’ values will be shown in red.
Example of emission values outside pre-programmed limits during high idle
At raised idle the CO, HC and Lambda values are compared to standards. In this example:
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The mixture is too lean (shown by the lambda figure) as one of the injectors is disabled. The figure is displayed in red.
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HC is low enough and the CO is low enough, to fall within 'legal' limits. The figures are displayed in black.
Idle speed test
At idle the Lambda is not gauged as many older vehicles enter open loop running at idle. In this case we are testing (and have selected) an older (non EOBD) vehicle. Yet:
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The mixture is still too lean shown by the lambda figure. The figure is displayed in black.
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HC is low enough and the CO is low enough. The figures are displayed in black.
The printout shows in red which values have failed
Below is another sample of a problem vehicle:
In this case the mixture is overly rich as a result of an airmass sensor problem.
The CO indicates very rich and turns red. The HC’s are high but not outside parameters.
The lambda figure shows very rich, but is not monitored at idle under the used 'official' test protocol.