Diagnostics can reveal:
- dirty or wet candles;
- contamination or change in nozzle performance;
- malfunctions in the fuel supply system (pressure regulator, fuel pump, etc.);
- violation of electrical connections in ignition and injection systems (reliable connection of high-voltage wires to spark plugs).
Diagnostics is carried out by measuring the change in the instantaneous speed of the engine crankshaft.
A drop in engine torque indicates incomplete combustion of the combustible mixture.
This diagnostic is performed almost constantly throughout the trip. Running this diagnostic or identifying a fault will disable other diagnostics «using the on-board diagnostic system» (catalytic converter and upstream oxygen sensor diagnostics).
Carrying out this diagnostic allows you to identify defects of two types:
- mixture misfires damaging the catalytic converter. At the same time, the signal lamp for a malfunction of the injection system immediately lights up with a flashing light;
- misfiring of the mixture, leading to an increase in exhaust gas toxicity above the threshold allowed by the on-board diagnostic system». If gaps were registered during three trips in a row, then the signal lamp for a malfunction of the injection system lights up with a constant light.
Troubleshooting Conditions
Before proceeding with the diagnosis, check that the programming has actually been done, and that all necessary conditions have been met, 8 including the conditions preceding the ignition on. Diagnostics is performed as soon as the coolant temperature exceeds -7.5 'C. in three engine speed ranges from idle to 4500 min-1.
The emissions misfire test can also be performed with the engine idling for 10 minutes and 40 seconds.
Attention! At the end of this test, never turn off the ignition before reading the result on the scan tool. Switching off the ignition leads to incorrect interpretation of the results.
Repair Confirmation
Mixture misfire diagnostics are performed: «ACTIVELY».
Passes leading to an increase in the toxicity of exhaust gases: «FAULT NOT DETECTED».
Mixture misfires leading to destruction: «FAILURE OF THE CA1ALIC NEUTRALIZER NOT DETECTED».
If the diagnostic system detects a misfire mixture after performing the test, refer to the diagnostic method corresponding to the malfunction.