RDT (fuel pressure regulator) in the people called "check valve" or "bypass valve". Most often, when the following engine problems arise: Power drop, unstable work at idle, bad launch, twigging - the fuel pressure regulator does not pay attention. And completely in vain, as to ensure normal operation of the engine, the RDT plays a far from the last role.

Fuel pressure regulator, why it needs a car where RDT is installed

The amount of fuel that enters the combustion chamber directly depends on the operation time of the nozzle, as well as from the pressure in the fuel rail, and pressure in the intake manifold.

To control these three factors and for a more accurate calculation of the amount of fuel in fuel recirculation systems, a fuel pressure regulator is installed. The RDT device is such that it can maintain a pressure difference: fuel pressure in the nozzle, and, at the same time, the air pressure inside the intake manifold. In this case, the fuel returns back to the highway in the fuel tank. To keep the difference in all nozzles, the fuel pressure regulator is mounted at the very end of the fuel rail.

In systems where fuel recirculation is not provided, RDT is mounted directly in the fuel tank. Due to the design features, the regulator can maintain the fuel pressure at the atmospheric pressure level. Thus, the difference between fuel pressure and pressure inside the inlet valve is not constant. For this reason, the difference is necessarily taken into account when the fuel mixture injection duration.

Device RDT.

Fuel pressure regulator is a simple unit, its detailed device is shown in Figure:

The valve holder is attached to the membrane, H presses the valve to the saddle. Fuel, which is supplied to the pressure chamber through intake passages, puts pressure on the membrane below. From above on the membrane presses the spring in the intake manifold. Sometimes fuel pressure can exceed the spring pressure. In this case, the valve opens through which the fuel enters the return highway. Thus, it is necessary to take into account the pressure inside the intake manifold.

In the process of operation of the fuel pump, fuel comes from the fuel tank to the filter, where it is cleared, after which is fed to the pressure regulator. RDT, in turn, constantly maintains the necessary fuel pressure in the system. In this case, all processes should flow synchronously.

The entire regulator system is in the steel case, which is capable of withstanding high pressure. The mechanism is equipped with a diaphragm, and a check valve that does not allow the fuel under pressure to return to the return highway.

How the fuel regulator works. Mode of operation of RDT

The main mode of operation of the RDT is idle. It is at this moment that the vacuum of the fuel mixture reaches the lowest point, and the pressure in the fuel ramp is the highest.
It must be borne in mind that the pressure in the ramp is directly dependent on the degree of pouring the fuel mixture inside the suction collector: the lower the vacuum, the higher the pressure.
In the process of work at idle, the indices of pressure and permanent reaches maximum indicators. The value of maximum pressure is applied to the Housing of the RDT, to carry out pressure control during the diagnosis of the fuel supply system.

Important moment: In most cases, the failure of the RDT does not make sense to repair, it is necessary to simply replace it with a new one. To avoid faults, the regulator must be regularly checked and follow the pressure in the fuel system. Regular preventive checks will help avoid breakdowns and save money to buy spare parts. In addition: regardless of the mode of operation, the RDT engine should clearly respond to all changes in operation.

If the RDT is faulty, as it affects the engine

If the car is working for a long time without a regular inspection and small repair, it inevitably leads to malfunctions in the work of one or several systems. If we speak specifically about the fuel pressure regulator, then most often, after some time, its spring gradually sends and does not create the necessary effort, as a result of which the fuel returns to the tank along the return highway.

This process significantly reduces the pressure in the fuel rail, which leads to a noticeable loss of engine power. Unfortunately, it is only one of the problems that arise with the defective RDT. So, the engine, losing power, begins to stroke at idle, when switching gears, the car is very badly gaining speed. In the process of movement, jerks may occur. In this case, the engine begins to chop out does not respond to the gas pedal, an increased fuel consumption occurs, etc. All "symptoms" of a faulty fuel pressure regulator will consider in detail below.

RDT is faulty, signs of problems, as a malfunction reflected at work

Some problems can be determined directly on rumor, but not all. Other breakdowns are manifested directly when the engine is running. Of course, such changes affect the operation of the car far from not at the better. Therefore, as soon as there is at least one of the symptoms listed below, it is necessary to urgently take action.
First of all, you need to check the status of the RDT if the following "Symptoms:

• The engine begins to work very unstable. Moreover, the motor does not "Troit" (as it happens with defective or dirty candles). The sound of the engine becomes uneven, resembling the lose of train on the rails.
• On small idle turns, the engine begins to stag. Of course, such a feature is characteristic of many problems: improper installation of the drive belt, dirty or flooded candles, contaminated carburetor, etc. So if only this "symptom" is present, many nodes will have to check.
• In the process of operation, the engine begins to work with jerks, "failures" begin, the fuel consumption increases sharply. However, again, all these signs on problems in different nodes, so it is extremely desirable to make final conclusions for the totality of signs.
• In the exhaust gases, there is a strong increase in carbon monoxide (can be checked or a special device, or "on s).
• When moving to a higher transmission, the car has long and weakly accelerates.

Causes of the failure of RDT

Actually, the main reasons are only two:

• Valve breakdown.
• The valve does not hold.

When the valve breakage of the RDT excess gasoline is not arrived back into the tank, as a result of which the pressure from 2.5 kg / cm2 and above increases. This malfunction inevitably affects the amount of fuel that enters the combustion chamber - that is, consumption increases much, while the fuel burns not everything and isted.

When the valve does not hold, gasoline, as they say, begins to "fumble" on the system. This reduces the head of the fuel, hence the occurrence of "failures" with a sharp increase in the engine revolutions. Some times the power and engine pickup is decreased, the load on the battery increases when starting, it accounts for a long time to turn the starter to create the desired fuel head.

How to check the RDT with your own hands. Council Prof.

There are several ways using which, you can check the status of the RDT in your garage. "Classic", it is the oldest option - to disconnect or override the bypass valve, while observing the force of the jet pressure. This method has been popular when checking pressure on vases. This time is practically not used.

Today, the easiest and most reliable method of checking is the use of a pressure gauge.

It is necessary to translate the engine for idle speed, after which it is necessary to connect the pressure gauge between the fuel hose and the fitting, pre-disconnecting the vacuum hose.
When measuring, the pressure in the fuel system should not grow more than 0.7 bar.

How to replace RDT with your own hands. Tools, appliances, equipment and consumables

To replace the fuel pressure regulator, many tools are not needed. Next:

• Keys - Hexagons of the required size (most often on "5").
• Wrench on "25". Hunting.
• Actually, the regulator itself.

Prepare this simple set, you can proceed to replace the RDT. Procedure Next:

We unscrew the plug of fitting, inside there is a corkstorn ring. Carefully inspect it. If there is damage - the ring broke, cracked, stretched, etc., then it is necessary to replace the entire plug.

Next, unscrew the spool from the fitting. The spool is exactly the same as on the wheels of the car, so it is not difficult to identify it.

Remove the vacuum pump from the check valve.

We unscrew the nut to which the fuel plum tube is attached.

We unscrew the hexagons with which the RDT is attached to the ramp.

Remove the reverse valve fitting from the holes of the ramp and the RDT itself disconnect from the drain tube.

After all the manipulations done, it remains only to install a new regulator. In this case, all work is carried out in reverse sequence. In the process of dismantling and installing RDT, no problems occur most often, except that the sealing ring can sometimes get stuck in the ramp, and it falls from there to choose.

If the ring is whole, it can be installed on a new check valve if not - replace.

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