Vehicle emission control system Honda Civic 3 and 4

Emission Control System Specifications
Crankshaft position sensor resistance: before 1987 (TDC and cylinder sensors) — 0.65-0.85 kOhm since 1988 - 350 - 550 Ohm Throttle position sensor resistance - 3.2-7.2 kOhm Air flow control valve resistance - 8-15 Ohm...

General information about the emission control system
In order to prevent emissions of harmful substances into the atmosphere and to ensure good economy, emission control systems for harmful components are introduced. They consist of: self-diagnostic systems; electronic...

Self-diagnostic system — description and error codes
Note: The self-diagnosis system is only installed on vehicles with PGM-FI fuel injection as an extension of the control system. If the instrument panel has PGM-FI indicators (models from 1985 to 1987.) or CHECK ENGINE...

Oxygen sensor — control and replacement
Control Models before 1988 1. The oxygen sensor is installed in the exhaust manifold. Disconnect the sensor connector. 2. Start the engine and set the speed to 3000 rpm. Wait for 2 minutes. 3. Increase the revs to 4000...

Absolute pressure sensor — inspection and replacement
Control Models before 1986 1. Check the condition of the vacuum hose between the throttle body and the sensor. Replace it if necessary. 2. Check the correct connection of the sensor electrical connector and the...

Crankshaft Position Sensor — Checking and Replacement
Models before 1988 1. On these models, the angular position sensor consists of two individual sensors: "TDC" and "cylinder". The "cylinder" sensor determines the position of the first cylinder as a base for counting the...

Throttle Position Sensor — Checking and Replacing
Control Models before 1988 1. The throttle position sensor is located on the throttle body. Disconnect the sensor electrical connector. 2. Measure the resistance between the black-brown and yellow-red contacts. Compare...

Air Flow Control Valve (1988 and Later Models) — Inspection and Replacement
Control 1. Turn off the ignition. 2. Remove the "HAZARD" fuse from the fuse panel for 10 seconds to reset the ECU memory. 3. Start the engine and make sure that the indicator "CHECK ENGINE" flashing. Stop the engine. 4....

Air temperature sensor (models with injection) — control and replacement
Control 1. With the engine cold, disconnect the sensor electrical connector, which is located on the intake manifold. Measure the resistance between the two sensor terminals and compare it to the specifications. 2. If...

Crankcase ventilation system
1. The crankcase ventilation system includes a positive pressure valve that reduces the emission of hydrocarbons with gases breaking through into the engine crankcase. Fig. 9.1. Typical crankcase ventilation diagram 2....

Fuel vapor recovery system
General description 1. The fuel vapor recovery system collects fuel vapors and mixes them with the finished fuel-air mixture while the engine is running. 2. The vapor accumulator is a container filled with activated...

Intake Air Temperature Control System (Carburetor Models)
General description 1. The intake air temperature control system ensures air heating during engine warm-up and maintains the intake temperature at about 40 degrees Celsius. This improves the conditions for the...

Ignition Timing Control System
General description 1. The ignition timing control system is designed to optimize the combustion process. Fig. 12.1a Ignition timing control system (models with carburetor) Fig. 12.1a Ignition timing control system...

Throttle control system
General description 1. The throttle control system reduces exhaust emissions, makes starting easier, and improves smoothness when shifting and decelerating. Fig. 13.1 Throttle control circuit 2. When the engine is...

Atmospheric pressure compensator
General description 1. The compensator is a device that controls the amount of air supplied to the small and large diffusers of the primary chamber of the carburetor and to the large diffuser of the secondary chamber....

Catalytic converter
General description 1. A neutralizer is a device installed in the exhaust system to reduce emissions of harmful substances. Neutralizers can be of two types: a) to reduce emissions of carbon monoxide (CO), hydrocarbons...

Exhaust Gas Recirculation (EGR) System
1. The EGR system reduces the content of nitrogen oxide (NO) by bypassing part of the exhaust gases to the engine intake. 2. On carburetor engine models, the EGR system consists of a bypass valve, two control valves and...

Air mixing system
General description 1. The system is designed to improve the operating conditions of the exhaust gas control system. Fig. 17.1 Typical secondary air mixing scheme Control 2. Entrust the inspection to the service station...

Gear shift control system for fuel-air mixture
1. The system prevents excessive enrichment of the mixture during gear shifting or vehicle deceleration. Fig. 18.1 Typical diagram of the mixture control system when shifting gears 2. Entrust the service station...

Feedback system
1. The feedback system ensures optimal preparation of the fuel-air mixture under different engine operating conditions. Fig. 19.1 Feedback system diagram 2. Entrust the service station personnel with monitoring the...

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Civic 8 (2005-2011)

Civic 7 (2000-2005)