Car lambda sensor

Lambda sensor is used in cars to measure the amount of residual oxygen in the exhaust. This value is used for optimization of fuel mix, in particular for controlling the ratio of fuel and air. At the optimum ratio most of the pollutants in the catalyst can be transformed into harmless substances. There are lambda sensors that react to jumps of resistance, of tension and broadband lambda sensors. Along with the oxygen content in exhaust gases, oxygen content in ambient air is also measured.

If the oxygen sensor is faulty, indexes of the exhaust gases are deteriorating. Control of exhaust emissions will help to identify the problem. Significant reduction of power during acceleration may also indicate a faulty oxygen sensor. Black smoke from the exhaust pipe is one of the signs that the lambda sensor has failed. Before dismantling check if the wire is in place. In modern cars information about lambda sensor functioning is displayed on the dashboard. The oxygen sensor cannot be repaired, it must be completely replaced. It is easy to replace the sensor and you can do it without any assistance.

The oxygen sensor is located between the catalyst and the exhaust manifold. The old tube is unscrewed and replaced by a new one. The presence of the inspection pit hastens the repair. After installation verify the exhaust value and analyse the indicators on the dashboard. Our online store offers you a wide assortment of car parts. You will easily find exhaust manifold, muffler, ESP, brake shoes, radiator grille, air filter, rear view mirrors and other car parts on our site.

Lambda sensor failure

• mechanical damages;
• overheating caused by ignition system faults;
• break of electric lines;
• short circuit;
• fuel soiling by gases and smoke.

Signs of Lambda sensors failures

• high percentage of toxic agents in exhaust gases;
• significant fuel consumption;
• vehicle dynamic performance decrease;
• unstable functioning of the catalyst;
• noticeable jerks at warmed up engine.

Causes of lambda sensor failures

• cooling or brake fluid ingress on the part;
• piston rings wear;
• usage of surface-active agents for lambda sensor body cleaning;
• impact of saturated petrol-air mixture on the part;
• high percentage of plumbic compounds in fuel;
• fuel filter clogging;
• loss of tightness of the lambda sensor body;
• ingress of fuel gases or air;
• interruptions in supply of the primary power supply with the electric power;
• increase of lambda sensor parts temperature because of low-quality fuel usage;
• element functional qualities worsening.

Diagnostics

A few simple steps are to be performed for diagnostics of the Lambda sensors. At first it is necessary to start and warm up the engine. Proper determination of residual oxygen level in exhaust gases is possible when the heating equals 300–400 °C. The assessment of frequency and form of a signal is determined by oscilloscope. Further it is worth finding out the exact values of resistance of the element heater at the room temperature. The indicator is normally equal 2–14 Ohms. After these procedures it is necessary to determine heater voltage at the working ignition system. Its desirable coefficient equals 10,5 V. The recommended frequency of Lambda sensors diagnostics is every 30 000 operational kilometers.

Repair and replacement of Lambda sensors

Only one type of defect removing is actual for a Lambda sensors. It is the cleaning from the soiling by smoke and gases.  Unmounting of the part is carried out at a temperature of 50 °C therefore it is necessary to warm it at first. Cleaning is made by placing the sensor into orthophosphoric acid for 15–20 minutes. Then the element should be rinsed in the clear water and dried up. After that, it is necessary to check a thread of component and to apply an assembly paste on it. It is important to distribute the paste accurately, without getting it on a protective tube of a Lambda sensors. Also you shouldn't apply it to the connector providing the oxygen supply.

If cleaning of the component didn't yield desirable result, it is necessary to replace the part. Replacement of the damaged element can be conducted by yourself or by means of the skilled technician.