Cleaning the lambda probe with your own hands
The control sensor measures the remaining oxygen in the exhaust. The sensor signal is used by the engine control unit to adjust the mixture. The sensor converts into an electrical signal the data about how much oxygen is contained in the exhaust gases. If the probe detects a change in measurement, it transmits an electrical signal to the controller and then compares it with the stored values in memory.
If they do not correspond to the reference values, the unit adjusts the amount of fuel injection. This ensures engine efficiency, gasoline savings and lower emissions.
On the basis of this signal the unit also detects malfunctions and informs the driver on the dashboard.
- ensures the perfect generation of the fuel mixture;
- guarantees optimal catalytic converter operating conditions;
- reduces harmful emissions;
- maintains the calculated fuel consumption.
Every car with an adjustable catalytic converter has at least one lambda sensor. Modern cars require at least two sensors. Motorcycles are also equipped with these mechanisms.
The internal structure of the sensor:
- Metal contact, for connecting connectors.
- Dielectric seal with air hole for safety.
- Closed zirconium electrode inside ceramic tip, heated to temperatures in the range of 300-1000 os.
- Gas shield.
The first signs of sensor failure
Experts advise diagnosing the sensor regularly, every 30,000 km of mileage, and replacing it after 100,000 km. Typically, manufacturers use this range to limit the life of the probe.
If motorists do not heed these recommendations, after passing the “anniversary” mark of 100,000 km, they will get the “Check Engine” alarm.
This fuel cell is not eternal. Since it works in an aggressive environment, it can fail at any time, even before the end of the warranty period. The driver notices the malfunction by the symptoms of the machine’s unit behavior. For example, in cases where the car is equipped with a fuel probe and the CO level is extremely high, it means that the control unit is not working.
Determine the content of harmful substances in the exhaust gases can be determined only with the help of gas analyzers. But it is an expensive device, and for personal needs it is unprofitable to buy it. Therefore, the breakdown is indirectly determined by the current consumption of gasoline and frequency of refueling. In addition, the signaling lamp on the panel indicates the presence of engine failure. If it is impossible to analyze the exhaust gases with a special device, it is done visually. Light smoke from the muffler is a sign that the mixture is bloated, and black signals of gasoline overspending and fuel system malfunction.
Diagnostics of Fuel Devices
The oxygen sensor is located at the epicenter of fuel combustion. The composition of gasoline has a significant impact on its performance. If it does not meet GOST and contains a lot of lead impurities, it will give an error signal to the electronic control unit or will fail at all. There are also other reasons for malfunctions:
- Mechanical vibration and intensive operation of the car leads to damage or burnout of the device housing, after which it cannot be repaired. The rational solution is to buy a new device.
- Improper operation of the fuel supply system. If the fuel-air mixture does not burn completely, soot begins to settle on the body of the probe, and also gets inside through the air intake holes. At the first cleaning of the device it is possible to eliminate the problem, but if the failures will occur frequently, then a new device should be installed.
Diagnostics on specialized equipment will give the most accurate answer about the breakdowns. It is also possible to detect the malfunction of the sensor on your own, it is enough to carefully read its characteristics, after which the driver will be able to decide whether it is possible to clean the lambda probe.
Preparing for the test
On modern cars, there are usually 2 sensors installed – before and after the catalyst. Signals from them should be different, then the control unit adjusts the injection duration according to the accepted parameters.
But if one of the sensors fails or the car owner has removed the catalyst option, the signals from the two sensors are perceived by the unit as an emergency mode. The controller in this case will select the average data to adjust the injection, which will increase fuel consumption and reduce engine power, and the Check Engine sign will appear on the panel. To combat this phenomenon, carry out a simple diagnosis of the sensor. It is necessary to work on a cooled engine, otherwise you can get burned.
- Open the hood and find the exhaust manifold.
- Find the probe on the catalytic converter.
- Perform exterior inspection. Soot, fouling are signs of a malfunctioning fuel system, indicating that there is too much lead in the gas.
- Replace oxygen sensor and diagnose the car again.
- Disconnect the sensor connector and connect a voltmeter to 2 volts.
- Start the engine at up to 2,500 rpm, then reduce it to idle.
- Measure the voltage. The change should be small, in the 0, 8 / 0, 9 volt range. If there is no transformation or the voltage is zero, this indicates a faulty sensor.
What kind of sensors are installed on the car?
On modern cars, the sensors that are put on a car are:
- Oxygen (also called lambda probe).
- Oil pressure.
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About the oxygen sensor and will be discussed in the article. Lambda probe allows you to perform several important functions at once. It significantly improves the performance of the engine due to the fact that the fuel is dosed correctly. Also, with its help, the harmfulness of the exhaust gas is reduced. More specifically, it improves the performance of the catalytic converter, greatly extending its life.
Mechanical cleaning of the converter
It is important to clean the oxygen sensor in a timely manner, so that the functionality of the car is not impaired.
If the driver neglects to clean the probe, it contributes to performance problems, reduced performance due to inefficient combustion.
Materials and tools needed:
- Goggles and work gloves.
- Car lifter.
- WD-40 and gasoline.
- Soft brittle brush.
- Paper towel.
Lambda probe cleaning is carried out in a safe manner. The motorist must first wear gloves, goggles and a face mask, as he will be working with gasoline during the recovery process. Sequence of Operations:
- Park the car in a clean, well ventilated and lighted area.
- Use a jack to raise the vehicle and keep it in position.
- Engage the handbrake so that the vehicle will not move when lifted.
- Install jack stands.
- Locate the oxygen sensors, which should be near the converter. There may be a different number of them, depending on make and model and release. You can refer to the owner’s manual for the exact location. Typically, one is placed in front of the catalytic converter and the other in the exhaust manifold.
- Spray lubricant on the sensors to make it easier to unscrew the boiled nuts.
- Wait 10 minutes and then unscrew them with a wrench.
- Carefully collect excess gasoline in a special container with a tightly closing lid.
- Do not leave sensors on the ground or in any other dirty place.
- Place the removed sensors in the container and slowly pour the gasoline into it. The amount should be enough to completely cover the instruments. After that, you need to allow the gasoline to break down the dirt deposits, and then rinse the container. If the dirt could not be cleaned immediately, the container should be left in a cool and dry place overnight.
- In the morning, check the contents of the container and make sure that most of the dirt is gone. But if anything remains, you can take a soft-bristle brush, dip it in gasoline, and gently rinse the probe.
- Let the probes dry completely for a while or dry them quickly by putting a paper towel over them.
- Put them back in their correct position by tightening all the screws.
- The restored sensor will now begin to work effectively, resulting in increased vehicle performance.
OXYGEN SENSOR (LAMBDA PROBE) REPAIR
Oxygen sensor is quite an expensive device. Therefore, car owners try to carry out lambda probe repair themselves. Most often it boils down to its cleaning. Cleaning the lambda probe with your own hands is carried out by removing fouling from the platinum electrodes of the ceramic rod. It can be carried out in one of the following ways (first carefully unscrew the sensor from the manifold pipe):
- Highly heat and then cool the sensor sharply. The soot should crack and fly off.
Useful tip: do not try to clean the ceramic rod mechanically. Doing so will damage the thin precious metal layer and permanently damage the sensor.
- In the protective cap, without disassembling the sensor, carefully expand the existing slots with a file and wash the electrodes with orthophosphoric acid.
Important! Do not completely immerse the lambda probe into the phosphoric acid.
- The electrodes can be thoroughly cleaned only by removing the protective cap. To do this, you need a lathe with which the protective cap is carefully cut off, and an argon welding machine to put it in place. These operations require a certain skill and are best carried out in a specialized workshop.
Warning: It is not recommended to use a metal saw to remove the protective cap. It usually damages the parts of the lambda probe.
Sometimes the lambda probe stops working due to broken wires (error 0140). In this case, you can also repair the oxygen sensor yourself. After finding the place of the breakage and restoring the electrical circuit, it is desirable to check all the contacts, which may be oxidized. You can clean them with WD-40.
Chemical surface treatment
There are many references on the Internet to cleaning the lambda probe with phosphoric acid – and not only with this agent. Someone has used various chemicals commonly used to clean bathrooms, plates and other kitchen furniture.
The main rule not to spoil the probes – do not scratch, that is, conduct cleaning without the use of hard brushes.
Cleaning with phosphoric acid received the most feedback. This is sold in stores and is used for soldering. It is poured into a glass and soaked into the probe. After 15 to 20 minutes, the dark stone deposits turn blue-green from the salt, which is easily washed off with water, due to its solubility.
After rinsing the probe becomes clean and shiny. The “check” indicator no longer lights up, and the fuel consumption is normalized. Thus, cleaning the lambda probe with acid is effective, but requires an increased level of safety due to the possibility of chemical burns.
Unfortunately, the service life of oxygen probes does not exceed 100 000 km. Failure of probes is hastened by the use of low-quality fuel or regular overheating. A simple method of cleaning at home significantly increases the working life of the lambda probe.
Methods of cleaning at home
Since the oxygen sensor can sometimes be repaired, car owners have a logical question. They wonder how to properly clean the lambda probe without going to a car service. Indeed, there are methods that can be applied at home. But you need to be very careful, since the work involves the use of potentially dangerous substances. Keep in mind that the oxygen sensor is quite fragile by design. Therefore, causing any damage during cleaning directly indicates that the work must be stopped, and a new controller must be bought. This one is already unsuitable for further use. The need to replace the lambda probe occurs when the vehicle begins to consume a large amount of fuel that exceeds normal values for no objective reason. Also on the dashboard appear warning lights, which recommend a diagnosis. Quite often such symptoms indicate exactly a problem with the oxygen sensor. And there are two methods of cleaning:
It is recommended to immediately abandon the idea of performing a mechanical cleaning. This is due to the fragility of the element, which is very easy to damage when working with your own hands. If any damage is done, further operation of such a controller is not allowed. It is also dangerous to use any electric tools with abrasive nozzles. They act with too much force, causing the sensor to break instantly. It is also long and exhausting to sit and pick the sensor with different toothpicks or needles. In the end, experienced motorists agree that the chemical method is the best, easiest to perform at home and effective.
When choosing a chemical cleaning method, it is important to choose the right product. Here you can use liquids from different manufacturers, which offer their own solvents for hard soot deposits. And many people wonder if you can clean the lambda probe at home with a carburetor cleaner. Such a tool can really help, as well as the injector cleaner. But still, orthophosphoric acid has gained more popularity. It is able to cope with more serious contaminants. Orthophosphoric acid is characterized by the ability to quickly dissolve metal oxides and organic alkaline films without damaging the oxygen sensor itself. Such cleaning gives a good result, so it is often carried out with their own hands at home, if the controller is not out of order, but just contaminated.
You can use orthophosphoric acid in an ordinary and improved way. To carry out cleaning work, you will first have to find the oxygen sensor itself. It is located in the under the hood before the catalyst installed on the car. But note that on modern cars, manufacturers put two lambda probes at once. The first one is in front of the catalyst, and the second is located behind it. Therefore, sometimes it is easier to find the devices by moving from the underhood space under the car. If there is a pit in your garage or you can lift the car on an elevator, it will not be difficult to find oxygen sensors. Controllers are disassembled with a wrench of the right size. After removal, you can proceed to cleaning. You will use the normal method or the accelerated method, everyone chooses for himself.
Conventional acid cleaning
You can not say that the independent cleaning of the lambda probe with orthophosphoric acid is extremely simple. And here it is not about the acid itself or the procedure. The difficulty lies in the fact that the ceramic-platinum base, on which accumulates fouling and soot, is hidden under a protective metal cap. If it is not removed, the treatment will be useless. To remove the cap, you need to be extremely careful and delicate. If you pick up a metal hacksaw, you are sure to damage the whole device, so no further cleaning will be necessary. You will have to replace the oxygen sensor. Here you can use a lathe with which you can cut off the cap near the threads. If you do not have a lathe, files are used. Completely remove the cap with a file is not possible. But it is possible to make a small window, the size of which will be about 5 millimeters. The optimal way, which does not require additional tools. When you manage to get to the working rod, you can start working on cleaning the lambda probe. Step by step it looks as follows.
Cleaning the lambda probe yourself
The exhaust gas of a gasoline-powered car engine contains 0.3-8% oxygen. The value for diesel is higher, and equals 2-18%. If the figure is out of the norm, the engine starts to work with malfunctions. The reason for this is the violation of the fuel-air mixture composition. This parameter is monitored by the oxygen sensor. It sends a signal to the ECU – electronic control unit, and the latter dynamically changes the composition of the mixture necessary for full detonation of the fuel. During operation, fouling forms on the sensitive element of the sensor. This article will talk about cleaning the lambda probe.
The device of the lambda
The structure of the lambda probe
The picture shows a heated lambda probe. The part is installed in the intake manifold and on the exhaust pipe after the catalytic converter. The gases penetrate through the holes in the shield and come into contact with the electrodes located on the surface of the ceramic tip. A sensing element measures voltage for zirconium sensors and resistance for titanium sensors. The signal goes through the wires to the ECU. The reference, or stoichiometric ratio of air to fuel is 14.7:1. This is λ=1, no mixture adjustment is necessary. But there are other options:
- Много воздуха, λ>1. Fuel is added.
- Little oxygen, λ
In the process, there is soot on the ceramic tip, which overlaps the electrodes. Readings become erroneous, the sensor stops doing its job. It can be cleaned with your own hands. Only the chances of restoring functionality are equal to 50%. The earlier the fault is found, the higher the probability of “resurrecting” the lambda probe.
Determining the type of sensor
The first thing to do is to understand what kind of lambda is installed in the car: titanium or zirconium. Why do this? The electrodes on the ceramic tip are made of different metals, which means different cleaning agents will be needed. Comparison chart:
There is a red core.
The surest way to identify it is to find the markings on the sensor body and check against the manufacturer’s catalog. The description will tell you the exact name. Only organic solvents or weakly concentrated acids can be used to remove titanium fouling. Zirconium lambda’s are not as sensitive. They can be cleaned at home with caustic chemicals.
Lambda probe with zirconium oxide and titanium oxide sensing element
The most vulnerable part of a lambda probe is the electrodes on the ceramic tip. You need to choose a product that is not capable of destroying the fragile metal, but can cope with fouling. The list of what not to use:
- Titanium oxide. TiO2. Heating with sodium, calcium, magnesium, and chlorine. Ammonia, hydrogen peroxide and sulfuric acid at room temperature.
- Zirconium oxide. ZrO .2. Alkalis, sulfuric acid in concentrations greater than 70%, hydrofluoric acid, aka hydrogen fluoride solution.
If you take away the exceptions, there is not much choice. Organic solvents such as dimethoxide and hydrocarbons will do for the role of reagents. Inorganic acids like orthophosphoric, hydrochloric and sulfuric acids will do the job. It is better not to use organic compounds. They only dissolve lime scale and rust. The soot will remain in place if you use citric or acetic acids.
The final result depends on the substance that is chosen as a reagent. The main indicator is the time spent. If you need to quickly restore the lambda probe, acids are unlikely to be suitable. Soaking will take several hours. The basic data is given in the table:
Cleaning time, hours
Inorganic acids will help clean the lambda probe with maximum efficiency. The time depends on the degree of contamination. But not longer than a day. Dimexide and other solvents can remove light contaminants consisting of hydrocarbons.
Important. To work with caustic substances, you will need PPE – personal protective equipment. These include rubber or nitrile gloves, a respirator and goggles.
To perform the procedure with maximum effect, you will need a minimum set of equipment. Glass beakers or jars of 150 to 250 ml can be used as vessels for immersion of the oxygen sensor. A toothbrush is needed for mechanical cleaning of the cap, and a household hair dryer will help heat the part. It is recommended to bring the temperature of the lambda probe to 80-90°C. This will speed up the chemical reactions.
The ceramic element is protected by a metal shield with holes for the penetration of exhaust gases. Some experts recommend cutting off the cap before cleaning. But this operation with insufficient skill can completely ruin the sensitive element of the sensor. In addition, the screen will have to be fixed in its former place with spot welding.
These substances include dimethoxide, kerosene and acetone. The first option provides medium effectiveness. Therefore, it should be taken as the basis. Dimethylsulfoxide is sold in pharmacies in the form of a solution or concentrate. It does not react with titanium and zirconium oxides, so it is safe for the sensitive element. It is better to work with the solvent in gloves, and the room should be carefully ventilated.
How to clean the lambda probe with dimethoxide
The first thing to do is to bring the cleaner to a liquid state. At temperatures of +18°C and below it precipitates, forming crystals. To soften it, you will need to heat it in a water bath. To do this, simply take a saucepan, heat water in it and immerse the vial with dimethoxide in the liquid. It remains to pour the prepared solvent into a glass container and dip the working part of the lambda probe into it up to the threads.
Periodically you need to heat dimethyl sulfoxide, otherwise it will crystallize. The whole procedure will take no more than an hour. There is no point in doing it longer. The substance should remove the soot in 30-60 minutes. The algorithm for soaking the sensor in kerosene and acetone is similar. Only you should not heat the solvent.
For titanium sensors, the maximum concentration of the active ingredient should not exceed 50%. Zirconium lambda probes easily interact with a solution that contains 75% acid. The first option can be found in electrical and electronics stores. The substance is sold as solder flux. Caustic, technical acids are easy to buy at an online store like Ozon.
The cleaning process at home looks like this:
- Heat the sensor with a hair dryer to 85° C and dip it into a solution of orthophosphoric acid to the beginning of the thread.
- Let it stand for the desired time depending on the degree of contamination. Minimum 1 hour, maximum 24 hours.
- Rinse the lambda probe in clean water, clean the outer surface with a toothbrush.
It is hardly possible to assess the condition of the ceramic tip after the procedure. The holes in the protective screen are too small. Therefore, you will have to check the part in operation after installation on the seat in the exhaust manifold or on the section of the exhaust pipe after the catalytic converter. If the engine runs smoothly and the OBD-2 scanner gives no errors, then everything is fine.
Cleaning the oxygen sensor with phosphoric acid
Some masters advise to heat the sensor with a gas burner after soaking it. This is hardly a good idea. The maximum working temperature of a zirconium lambda probe is 300°C, and a titanium one is 700°C. A burner can produce 1300°C. There is a risk that the metal contact grid on the ceramic tip will simply melt.
Sulfuric and hydrochloric acids
Cleaning the lambda probe with sulfuric acid is a dangerous but effective method of removing fouling. The procedure can be performed with your own hands. The main thing is to buy a sufficient amount of the substance. It is in the composition of the battery electrolyte. True, the concentration is not so great. It depends on the density: