Checking the composition of exhaust gases [Toyota RAV4 XA20]

Models with gasoline engines

Note 1. Below are the standards for the content of harmful impurities in the exhaust gases of vehicles with gasoline engines, in force in Russia at the time of writing this Guide. The standards are regulated by GOST R 52033-2003, introduced on 01.01.2004 to replace the previously valid GOST 17.2.2.03-87.

Note 2. The following terminology is used in GOST:

• A two-component exhaust gas aftertreatment system is a system that reduces the content of exhaust gases, primarily carbon monoxide and hydrocarbons, without feedback on the composition of the working mixture.
• Three-component exhaust gas aftertreatment system - closed-loop system (by the excess air coefficient λ), ensuring a reduction in the content of carbon monoxide, hydrocarbons and nitrogen oxides in exhaust gases.

• The content of carbon monoxide (CO) and hydrocarbons (CH) in the exhaust gases of vehicles is determined with the engine idling for two crankshaft speeds set by the manufacturer for a given model: minimum (n min) and increased (n pov).
• If such data is not available, then the check is performed under the following conditions:
• The value of n min should not exceed 1100 min⁻¹;
• The value of n pov is set within the range of: 2500-3500 min⁻¹ for vehicles not equipped with an exhaust gas neutralization system; 2000-3500 min⁻¹ for vehicles equipped with an exhaust gas aftertreatment system.
• To perform this work, you will need an exhaust gas analyzer with a relative error of no more than 6%:
• for models not equipped with neutralization systems or equipped with two-component (oxidizing) neutralization systems, a two-channel gas analyzer designed to measure the content of carbon monoxide (CO) and hydrocarbons (CH);
• for models equipped with three-component neutralization systems; — four-channel gas analyzers designed to measure the content of CO, CH, carbon dioxide (CO₂) and oxygen (O2).

Four-channel gas analyzers can also be used to perform measurements on vehicles not equipped with neutralization systems or equipped with two-component neutralization systems.

If you don't have such a device and can't borrow it for a while, almost any auto repair shop will do this work for you for a reasonable fee.

• Before starting measurements, check the vehicle for the presence of systems and devices that reduce harmful emissions. If the actual vehicle configuration does not match that specified by the manufacturer, there is no point in taking measurements – you will not pass the technical inspection.
• Before taking measurements, the vehicle engine must be warmed up to a temperature not lower than the operating temperature of the engine oil or coolant specified in the vehicle operating instructions, but not lower than 60°C.
• After warming up the engine, the car should be prepared for measurements in the following order:
• Install the gear shift lever (or a mode selector for cars with an automatic transmission) to neutral position;
• Apply the parking brake and turn off the engine;
• Connect the tachometer and oil temperature gauge sensors (if it is included in the measuring equipment kit);
• Insert the gas analyzer sampling probe into the vehicle exhaust pipe to a depth of at least 300 mm from the cut-off point (when the exhaust pipe is cut at an angle, the depth is measured from the short edge of the cut).
• On models not equipped with an exhaust gas aftertreatment system, perform measurements in the following order:
• Before taking measurements, check and set the gas analyzer readings to zero on the CO and CH measurement scales;
• Start the engine by pressing the throttle pedal, increase the engine speed to n revs and operate in this mode for at least 15 seconds;
• Release the accelerator pedal, set the minimum engine speed n min and no earlier than 30 seconds later measure the content of carbon monoxide CO and hydrocarbons CH; — set the engine speed to high n min and measure the CO and CH content no earlier than 30 seconds later.
• On vehicles equipped with an exhaust gas aftertreatment system, perform measurements in the following order:
• Before taking measurements, check and set the gas analyzer readings to zero on the CO, CH and CO₂ measurement scales;
• Start the engine by pressing the throttle pedal, increase the engine speed to n rpm, maintain this mode for 2-3 minutes (at an ambient temperature below 0°C - 4...5 minutes) and after the readings have stabilized, measure the content of CO, CH, and also record the value of the excess air coefficient λ.;
• Set the engine speed to minimum n min and measure the carbon monoxide and hydrocarbon content no earlier than after 30 seconds. Measurements at n min should be started no later than 30 seconds after checking in n turn mode.
• On vehicles equipped with a three-component exhaust gas neutralization system and a built-in diagnostic system, before measuring the CO and HC content, the engine and neutralization system performance is checked using the readings of the diagnostic indicator located on the instrument panel:
• When you turn on the ignition before starting the engine, the diagnostic indicator should come on for a short period of time; if there is no corresponding signal from the diagnostic indicator after turning on the ignition, the further testing procedure is stopped;
• After starting the engine, the diagnostic indicator should turn off; if the diagnostic indicator remains on while the engine is running, the further testing procedure is stopped.

Content of CO and CH in exhaust gases

• The CO and CH content must be within the limits set by the vehicle manufacturer, but not more than:

Vehicle equipment	ndv	CO%	NS, million⁻¹
Cars manufactured before 01.10.86	nmin	4.5	-
Vehicles not equipped with an exhaust gas aftertreatment system	nmin	3.5	1200
	npov	2.0	600
Vehicles equipped with a two-component exhaust gas aftertreatment system	nmin	1.0	400
	npov	2.0	200
Vehicles with a three-component exhaust gas neutralization system and equipped with an on-board diagnostic system	nmin	0.5	100
	npov	0.3	100

• The value of the excess air coefficient λ in idle mode at n_pov for vehicles equipped with a three-component neutralization system, it must be within the data limits established by the manufacturer. In the absence of such data, λ should be between 0.97 and 1.03.

Models with diesel engines

• The only test that diesel engines undergo (according to GOST 21 393-75), consists of measuring the density of smoke in exhaust gases. Tests are carried out in free acceleration mode and in maximum speed mode.

Note: For the test to be successful, it is extremely important that the camshaft drive belt is in good condition. Below are the maximum permissible standards for smoke emission from diesel engines:

Measurement mode	Smoke content, %, no more than
When the crankshaft rotation speed increases: naturally aspirated	40
supercharged	50
At maximum shaft speed	15

• Increased levels of exhaust smoke may be caused by a dirty air filter. In other cases, a professional consultation will be required to determine the cause.

Requirements for the technical condition of the car and engine

Exhaust system	Completeness (the absence of any elements of the exhaust system is not allowed). Tightness (exhaust gas leakage due to loose connections, rust, mechanical damage, etc. not allowed).
Neutralization system and other equipment for reducing harmful emissions	Completeness (absence of any elements of the neutralization system, fuel vapor recovery system, exhaust gas recirculation, etc. not allowed)
Crankcase ventilation system	Completeness of the system. Sealing of elements.
Built-in engine diagnostic system	Functioning of the diagnostic indicator corresponding to the correct operation of the engine (the indicator is off when the engine is running)