Idling carbon monoxide content (SO) in the exhaust gases should be 0.5±0.2%. If it is less, then this may be due to the following reasons:
- engine intake leak (after air flow meter);
- malfunction of the additional air supply valve;
- malfunction of the fuel pressure regulator;
- partial clogging of the fuel filter;
- discrepancy between the discharge pressure of the fuel pump and the nominal value;
- malfunction of the electronic control unit;
- malfunctions in the electronic devices of the fuel injection system (to check them, use the Bosch tester 0.684.100.202).
The reasons for the increased CO content can be:
- insufficient tightness of the oil dipstick;
- increased oil level in the oil sump;
- leaking intake or exhaust valves;
- malfunction of the air flow meter;
- non-shutdown of the starting nozzle;
- malfunctions in the electronic devices of the fuel injection system (to check them, use the Bosch tester 0.684.100.202);
- injector leaks.