Smells like gasoline from the exhaust. The smell of gasoline when starting the engine: the main reasons. What to do if the muffler smells of gasoline

Let's start with the fact that during the operation of the vehicle, drivers in some cases note the appearance of a distinct smell of gasoline in the cabin or while being near the car.

It is important to understand that this symptom indicates the need for immediate diagnostics, since the smell of fuel often indicates depressurization and fuel leaks.

In this article, we will talk about why the smell of gasoline appears in the cabin when the engine is started or it smells like fuel when you are near a car with a running or muffled one, and also what the driver should do if such a malfunction is detected.

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There was a smell of gasoline in the car: causes

So, we note right away that the smell of gasoline in a car may not appear constantly, but only under certain conditions. For example, in severe frosts or in hot weather, when a cold engine is just starting or after the power unit has warmed up, when refueling a full one, etc.

In any case, it is necessary to establish the reason why the smell occurs. Note that in some cases it is quite difficult to quickly solve the problem. It is necessary to check the elements of the fuel system in stages.

• First of all, you need to start the diagnosis with the gas tank and its cap. The tank, especially on older cars, can rot. The tank mounts also suffer, as a result of which it begins to shift. Also, over time, places of welds, etc. become unusable.

Also, the possibility of mechanical damage should not be excluded. One way or another, but even a slight leak will mean that the fuel flows out, filling the interior of the car with fumes, etc.

Special attention is also deserved by the cap, which is screwed into the filler neck. In many cases, this place is the source of the smell of gasoline. The fact is that the lid not only tightly closes the tank, but also has an additional valve.

The specified valve is needed in order to avoid an increase in pressure in the tank during temperature fluctuations and the expansion of gasoline with heating. If the valve is clogged or wedged, and there are problems with the cap seal, then a distinct smell of gasoline will appear.

• We go further. If everything is normal with the tank, then you need to inspect the fuel line, joints and clamps, and also check the integrity of the pipes. On the specified highway, gasoline is both supplied to the internal combustion engine (supply), and its excess is returned back to the tank (return).

Hoses may begin to leak, the reliability of their fastenings deteriorates. It is quite obvious that in this case a leak also occurs, and gasoline vapors will annoy the driver with the smell of fuel in the cabin.

The next item to check is the fuel pump. On vehicles with the fuel pump is often located under the hood or outside the tank. At the same time, a submersible gasoline pump (located in gasoline for fuel intake and cooling), that is, it is actually “screwed” into the gas tank. As a rule, on many cars with an injector, the pump is located under the rear seat right in the passenger compartment of the vehicle.

If there are problems with the gasket at the installation site of the electric pump, the thread of the cover is cracked or damaged, etc., then a persistent smell of evaporating gasoline appears in the cabin.

Fuel filters, especially when dirty and reduced throughput, can also be the cause of the smell of gasoline in the car. The reason is an increase in pressure in the fuel line, after which the joints of the pipes begin to flow, gasoline can flow at the “inlet” before or at the “outlet” after the filter itself.

To eliminate this reason, the fuel filter must be changed, and as part of further operation, it is necessary to correctly select the element for a specific car and replace the filter according to the regulations, avoiding severe contamination of the filter element.

• The fuel supply system with a carburetor requires a separate check of this fuel supply system to the engine. Often, at the same time, its incorrect adjustment or device malfunctions lead to the fact that gasoline overflows.

Naturally, the active evaporation of fuel in the engine compartment will cause gasoline vapors to enter the passenger compartment. To prevent this from happening, it is necessary to correctly adjust the fuel level in the float chamber, check the condition of the jets, regularly, etc.

Why does it smell like gasoline when starting the engine "cold" or "hot"

Note that if the smell of gasoline is heard only for some time after starting the injection engine, then this is not a malfunction in all cases. Often, the smell of fuel appears after a cold start in winter, then completely disappears as the power unit warms up. If so, then you need to understand the following:

• receives information from, which "reports" that the unit is cold.
• Based on this information, the control unit enriches the mixture, and significantly, and also increases the speed to the so-called "warm-up".
• Under conditions of operation on a re-enriched mixture in the cylinders of a cold engine, the fuel does not burn out completely, part of it enters the exhaust system.

It turns out that the smell of unburned gasoline that the driver feels comes from the exhaust pipe. After a slight warm-up of the engine, the fuel will begin to burn more fully and the smell will disappear. A similar situation for many cars can be considered the norm.

However, in some cases it is also appropriate to talk about malfunctions, especially on modern cars that meet the Euro-4 standard and higher. The fact is that incomplete combustion of fuel can occur not only as a result of re-enrichment of the mixture by the ECU itself to maintain stable operation of the internal combustion engine after a cold start, but also for other reasons.

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This problem worries many motorists, because they are well aware that you should not joke with gasoline. But another nuisance is added to this problem - fuel consumption increases. If such a problem is found, then the first thing to do is to inspect the entire body of the car from the hood to the fuel tank. Sometimes it happens that the nut of the fitting for supplying the fuel line to the carburetor loosens. The radiator fan blows gasoline vapors back to the muffler.

After finding the cause of the malfunction, the car must be put on a viewing hole and very carefully trace the path of fuel from the fuel tank to the carburetor, and if the engine is injection, then to the injectors. It will be necessary to tighten all fittings and clamps on the connecting hoses of the fuel line.

Often, on domestic cars, for some 3-5 years of operation, the gas tank turns into a sieve. If during the inspection no gasoline leaks were found, then you should try to study this problem in as much detail as possible.

Possible engine problems

Is the smell of gasoline coming from the muffler and is it not very comfortable to drive a car? Then, the first thing to do is to unscrew the candles and try to understand in which of the cylinders the fuel does not burn out and passes further along the exhaust manifold. A wet or greasy spark plug will show the location of a gasoline leak.

It is not uncommon for the chamfer of one of the exhaust valves in the combustion chamber to burn. It is from there that the fuel-air mixture exits into the exhaust pipe. The penetration of the gasoline mixture can be eliminated by an experienced auto mechanic.

It will be necessary to change the rings on the pistons, the valves, and sometimes the pistons themselves. So, we can assume that the average repair of the power unit is provided to the car owner. However, there is no need to rush into repairs, first it is better to diagnose the motor, because not always and not everything is so hopeless.

A poorly fitting spark plug cap or high voltage wire can cause the spark plug to malfunction. This may allow fuel to flow freely into the exhaust manifold. There is no need to be afraid if some kind of liquid suddenly pours out of the muffler, because this is not fuel, but condensate formed on the muffler walls when the engine was started. It certainly can exude the smell of gasoline, but do not worry, it's not gasoline.

Problems of a modern engine

If you drive a modern injection car, and from the “Glushak” “rushing” like the old “Volzhan”, we can conclude that the fuel is being re-enriched. The reason may be the incorrect operation of the lambda probe. Injector cars have a valve that regulates the discharge of unburned fuel back into the gas tank. If it breaks down, gasoline will be very enriched. A similar problem can be created by a failed air mixture sensor. An auto electrician will be able to very quickly "deal" with such a malfunction.

What to do if the muffler smells of gasoline?

First of all, do not panic, for this can be easily explained. The task of the collector, located in the exhaust pipe, is to clean and burn out the fuel vapors that remain in the exhaust gases. Until the catalyst warms up to 250 degrees, it will not clean anything, because its operating temperature is 600-800 degrees. Therefore, it is recommended that as soon as the car starts, go. This will allow the catalyst to warm up faster.

It becomes completely uncomfortable in the car if the smell of gasoline suddenly appears in the cabin. As a rule, it serves as a harbinger of trouble. Most likely there was a fuel leak somewhere. This can happen in many places, but you still need to find and eliminate the source of the smell.

The smell of gasoline in the car

There are several reasons for the smell of gasoline in the passenger compartment of a car. Sometimes it is difficult to determine where it comes from. Moreover, the smell of gasoline sometimes occurs only under certain certain conditions, for example, on a fully loaded car, or when the tank is filled. But, nevertheless, several places are well known that can serve as sources for the spread of fuel aromas:

1. Car tank. It can leak, and then fuel will begin to leave through the hole formed, and its fumes will penetrate into the passenger compartment. The reasons why this happens can be very different, ranging from damage to the tank mount, as a result of which it begins to move, and ending with leaking welds.
2. Tank cap. Sometimes the smell of gasoline comes from here. To ensure tight closure, it is equipped with a special gasket and a valve that relieves excess pressure when the fuel expands. If the gasket cracked over time, or the valve is faulty, then they will serve as a source of aroma.
3. Fuel line, clamps and pipes. It is through them that gasoline from the tank goes to the engine, over time, hoses can begin to leak and their attachment points weaken. Then fuel will begin to leave through them, which will cause the penetration of fumes into the cabin.
4. Gasoline pump. When it is defective or clogged, it may well become a source of unpleasant odors. On an injection machine, the pump is in the tank, while on a carburetor it is outside it. And if in this case the gasket at least just leaks at the pump, then the smell of gasoline will be provided.
5. Fuel filter. It is quite possible that during long-term operation it will be clogged with dirt, the pressure in the line will rise, which will cause leakage, for example, clamps. To eliminate the unpleasant and odorous fumes that occur, it is enough to replace the fuel filter.
6. Carburetor. If the adjustment is incorrect, the fuel will overflow, and its fumes under the hood will serve as a source of unpleasant odors.
7. The ingress of unpleasant odors from the outside. Particles of unburned fuel from an oncoming or passing car entering the passenger compartment through the outside air intake system while driving can also serve as a source of an unpleasant odor.

The smell of gasoline when starting the engine

The situation looks somewhat different when starting the engine, especially in winter. At the same time, the smell of gasoline is quite often felt, sometimes so strong that it gives the impression of a stream of fuel pouring out. However, if after warming up the engine it disappears, there is nothing to worry about.

When starting a cold engine, the ignition controller in the car makes the mixture too rich. As a result, part of the fuel does not burn and is thrown out of the exhaust pipe into the street, which is why the smell of gasoline will be felt.

This can happen even due to one idle engine cylinder, but if this is a permanent defect, then it will be accompanied by other manifestations, such as loss of power or deterioration in driving dynamics.

If a similar phenomenon exists only at start-up and disappears when the engine warms up, then it is associated only with a cold start, when the temperature rises, the normal operation of the motor should be restored.

The smell of gasoline from the exhaust pipe

In this case, the situation is not so clear. Of course, the smell of gasoline coming from the exhaust pipe can also be caused by a rich mixture, as with a cold start, but this problem should be considered a little wider. The smell indicates incomplete combustion of fuel, but the reasons may be different.

These include wires, candles, ignition coils, DMRV, lambda probe, catalyst and much more. Such a variety of reasons makes it difficult to independently determine why the smell of fuel comes from the exhaust pipe. Therefore, it would be best to call in for a diagnosis.

Gasoline smell in engine oil

It is especially worth mentioning the situation when fuel is found in the oil. This may be indicated by the smell of gasoline from the oil filler neck. The reasons may be:

• incomplete combustion of fuel;
• cold engine starts and driving on a cold engine for short distances;
• idle cylinders;
• frequent operation of the engine at idle (city driving mode);
• penetration through solenoid valves or nozzles;
• worn or loose injectors.

The consequence of this will be dilution of the oil and loss of viscosity, which worsens lubrication conditions, especially assemblies subjected to significant loads. Serious damage can occur when the engine is frequently started cold. If the engine is well warmed up, then gasoline evaporates and does not adversely affect the oil.

Many drivers are familiar with the situation when, when starting the engine, it smells of gasoline from the exhaust pipe or its smell enters the car interior. This should serve as a factor indicating certain problems. In such cases, you must independently take the necessary measures or call on the service station for diagnostics.

It is worth remembering that both gasoline itself and its vapors are explosive, and you should definitely not joke with such things.

Causes of the smell of gasoline from the exhaust pipe, when starting the engine, in the cabin

We are already accustomed to our own car, which not only can help us simplify life by significantly reducing the distance, or rather the time spent to move from point "A" to point "B". But this is if the car works like clockwork. However, it is worth some problem to appear and you have to look for ways to solve it, often spending substantial amounts only on diagnostics. However, some of the problems can be found on your own. The main thing is to know at least where to look and what to look for. Let's consider the problem when you suddenly start to smell gasoline that appears in the cabin and where it should not be at all. This problem is one of the most important and requiring urgent solution, as it can serve as a warning that more serious problems may soon appear. And most often, the smell of gasoline indicates a fuel leak that has occurred and it is impossible to leave everything as it is. Consider the main places where the smell of gasoline can appear, where it should not be.

The main reasons for the smell of gasoline in the car

There may be several reasons for this. Moreover, it will be difficult to immediately figure out why and how the smell of gasoline penetrates into the cabin. And yet, this is not always a wake-up call. For example, the smell of gasoline appears if the car is overloaded, or you just filled the tank. And if the smell appeared suddenly, then it is worth inspecting the car at the first opportunity. Here are a few places where the smell of gasoline can come from in the cabin:
1. Car tank. In this case, the problem arises if holes of various origins have formed in the tank itself, as a result of which fuel is lost. At the same time, its evaporation through various technical openings can also penetrate into the car interior. What can serve this? There can be many reasons. First of all, it can be a banal wear of both the tank itself and the mounts, as a result of which it gets damaged while driving on our “ideal” roads, welds can diverge.
2. Tank cover. It happens that the smell of gasoline penetrates into the cabin through the cover. The reason may be the wear and destruction of a special gasket or valve that serves to tightly close the cap and relieve, if necessary, excessive pressure in the tank when the fuel begins to expand. It is solved by replacing the cover or replacing the gasket - as it is convenient for anyone.
3. Fuel line, including clamps and pipes. If the tank and cap are normal, then we begin to track the paths along which the fuel enters the engine. The thing is that nobody canceled the wear and over time, leaks occur in the hoses, the fasteners weaken, as a result of which the fuel leaves, and its smell appears in the cabin.
4. Gasoline pump. As a result of a malfunction or blockage, gasoline odors can spread and enter the passenger compartment. Just in case, you should know that injection machines are equipped with a pump in the tank, while carburetors have a pump under the hood of the engine. Experts say that even if the gasket starts to leak at the pump, this can also give an unpleasant smell in the cabin. The problem is solved when inspecting the fuel pump.
5. Fuel filter. During long-term operation, bad gasoline, the fuel filter will inevitably clog, which causes an increase in pressure in the fuel line. As a result, leaks occur, and with them an unpleasant smell in the cabin. The problem is solved by replacing the fuel filter.
6. Carburetor. If your car is equipped with a carburetor, then if it is incorrectly adjusted, the fuel simply overflows. As a result, fuel vapors enter the passenger compartment. The problem is solved by adjusting the carburetor.
7. External reasons for the ingress of gasoline odors into the cabin. It can be exhaust from a car ahead or towards you when you are in a traffic jam or at a traffic light. They enter through the air intake system while driving, and this cannot be avoided.

Other reasons for the penetration of the smell of gasoline into the interior of the car

Reason 1. The smell of gasoline enters when starting the engine
It is especially acute in winter. There may be a feeling that a breakthrough has occurred and fuel is flooding the engine. Disappears after the engine is fully warmed up. If the smell has not disappeared, then it is worth starting a more detailed examination, starting from the places listed earlier. It happens because to start a cold engine, the ignition controller creates a re-enriched fuel mixture, which gives such an unpleasant effect.
Another reason is if one or more engine cylinders have failed. But this will immediately become noticeable, as power drops significantly, deterioration in driving dynamics and, at the same time,. The constant smell of gasoline under the hood and in the cabin.

Reason 2. The smell of fuel from the exhaust pipe
This may be a cold start, when unburned gasoline particles are present in the exhaust. If the problem does not disappear with warming up and the smell continues to be felt, then it is worth checking the spark plugs, mass air flow sensor, lambda probe, etc. If after that the problem is not solved, then there is only one way out - service stations and diagnostics.

Reason 3. The smell and the fuel itself appeared in the engine oil
There are several reasons why there is a smell of fuel from the oil filler neck. It is worth mentioning the main ones:
incomplete combustion of gasoline occurs;
as a result of a cold engine start.
the movement of the car without warming up the engine for short distances;
problem with cylinders;
the engine often runs at idle, which happens in the city or during a long wait;
as a result of wear or loosely closed nozzles.
Is it worth it to say that the fuel that gets into the oil leads to a loss of oil viscosity and therefore worsens the quality of lubrication of engine components and assemblies operating under load. And it is especially bad to use a car with an unheated engine, since the heated gasoline simply has time to evaporate and can no longer cause much harm.

We have listed the main options, due to which the smell of gasoline can end up in the car. And in order to avoid big problems, it is still worth visiting the service station and making a complete diagnosis. Perhaps in the future it will save your life, or it may prevent a major breakdown.

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