All engines with electronic fuel injection systems are equipped with devices that support the required fuel pressure in the fuel line. In the power unit of the VAZ-2114, this function is performed by a special regulator. It is thanks to him that gasoline flows under pressure to the nozzles in the right amount, depending on the mode of operation of the engine.
In this article we will talk about what the VAZ-2114 fuel pressure regulator is, how it is arranged and where it is located. In addition, we consider its possible malfunctions and methods for their elimination.
Design features and principle of operation
Structurally, the fuel pressure regulator VAZ-2114 is a membrane bypass valve enclosed in a metal housing. It is mounted on a ramp, inserted into it by one of the pipes through a rubber seal. The other output of the RTD is connected to the fuel line. To determine the load on the engine, the regulator is connected to the intake manifold by a vacuum hose. Thus, on the one hand, the membrane acts on the fuel coming under pressure from the gasoline pump, and on the other hand, the air pressure and the force of the valve spring.
The fuel pressure regulator VAZ-2114 has a fairly simple principle of operation. When you press the accelerator pedal, excess pressure is created in the intake manifold , which opens the valve, allowing more fuel to enter the ramp. When the throttle is closed, the air pressure in the intake pipe weakens. The valve opens in the other direction, releasing gasoline back into the fuel line.
Symptoms of RTD malfunction
A defective fuel pressure regulator VAZ-2114 does not pose a critical threat, however, its failure violates the stable operation of the engine. Symptoms of ruptured RTD include:
- difficult start of the power unit;
- unstable crankshaft idle;
- decrease in power characteristics of the motor;
- loss of dynamics;
- the occurrence of "failures" when you press the accelerator pedal;
- increase in fuel consumption.
Having found the listed signs of an RTD malfunction, you should diagnose the device and determine the cause of the breakdown.
Possible faults of the RTD
Given that the design of the pressure regulator is mechanical, disturbances in its operation can occur quite often. The most common device malfunctions include:
- weakening of the membrane spring;
- jamming (wedging) of the valve;
- clogged regulator;
- violation of the tightness of the junction of the regulator and the ramp body.
The weakening of the membrane spring leads to the fact that the valve can not cope with the pressure of the air coming from the intake manifold. As a result, the pressure and the amount of incoming fuel are reduced.
Jamming of the valve leads to an uncontrolled supply of fuel to the manifold and its “withdrawal” into the fuel line. In this case, the gas consumption increases, and the engine ceases to start normally due to interruptions in the supply of fuel.
Similar symptoms of malfunction can be observed with clogged regulator. Dirt and deposits reduce the throughput of the system, as a result of which the fuel pressure is significantly reduced, the engine “chokes”, and normal idling disappears.
If the connection between the regulator and the ramp is not sealed, the air pressure may drop, which again will lead to a decrease in fuel pressure.
What you need to check the pressure in the system
In order to make sure that the RDT, as well as the entire fuel system, is in good condition (malfunction), it is necessary to determine the fuel pressure. Naturally, this will require a special tool.
It is called a fuel gauge. It is better if it has a mechanical design and a scale of up to 10 kg / cm2. In addition to the fuel gauge, you will need:
- a piece of a high pressure hose (inner diameter 8-10 mm);
- several hose clamps corresponding to the diameter of the hose;
- pliers;
- screwdriver;
- cap for the nipple;
- tank for collecting fuel;
- dry clean rag.
Pressure Measurement Modes
Before checking the pressure in the fuel rail, it will not be out of place to find out how this process is carried out. In order to be able to more accurately determine a possible malfunction, pressure measurements must be carried out in several modes:
- with the ignition on (without starting the power unit);
- when the engine is idling;
- with a vacuum hose disconnected from the regulator (to check the performance of the RTD);
- with blocked fuel return hose;
- in rebase mode.
What should be the pressure when measuring in different modes
According to the manufacturer, for VAZ-2114 the pressure in the fuel rail should be:
- with the ignition on - 2.9-3.0 kg / cm2;
- with the engine running - at least 2.5 kg / cm2;
- with the vacuum hose disconnected - 3.3 kg / cm2;
- with a blocked return hose - 7.0 kg / cm2;
- with gas relocation - 3.0–2.5 kg / cm2
How to check the pressure in the fuel rail
The procedure for conducting pressure measurements is as follows. First, we connect the fuel gauge to one end of the hose, fix the connection with a hose clamp. We unscrew the cap on the fuel rail (on the side opposite to the one where the RTD is installed). We substitute a tank for collecting fuel under the fitting. With the cap for the nipples, we press the central protrusion, thus bleeding off the fuel pressure in the system. This process is required! Next, without removing the containers, unscrew the locking nipple completely.
When the remaining fuel drains into the tank, we put the other end of the hose onto the fitting and fix it with a hose clamp. We turn on the ignition and wait until the fuel pump pumps fuel into the system. We check the pressure and compare it with the recommended one.
After that, we start the engine and take measurements at idle. The performance check of the fuel pressure regulator is carried out with the vacuum hose disconnected from it and on the working power unit. If the pressure has increased to 3.3 kg / cm2, the regulator can be considered serviceable. If it has not changed, the RTD has most likely become unusable.
Similarly, we measure the pressure with a blocked hose "return", as well as in the rebase mode.
Repair or replacement
If the check confirms the fault of the RTD, it must either be repaired or replaced. However, it should be noted here that it is simply impossible to buy at least some spare parts for this device, so it is much easier to purchase a new VAZ-2114 fuel pressure regulator, the price of which does not exceed 800 rubles.
RTD replacement
Replacement of the RTD can be carried out both with the fuel rail removed and without dismantling it. The latter option is preferable, since it requires less time. But before you remove the fuel rail or the regulator itself, do not forget to reduce the pressure in the system as described above! Otherwise, the entire engine compartment will be sprayed with gasoline.
So, we will consider how the VAZ-2114 fuel pressure regulator is replaced without dismantling the ramp. This will require:
- a key on "10";
- a key on "17";
- a key on "24";
- hexagon on "5";
- cross-head screwdriver;
- clean dry rag.
Work order
- First, disconnect the negative terminal from the battery (key to "10").
- We disconnect a vacuum hose of a regulator from the union of an inlet collector.
- Using the wrench to “17”, unscrew the nut that secures the drain hose. Disconnect the hose.
- Use a Phillips screwdriver to unscrew the bolt on the pressure strip of the return pipe.
- Using the hex key on “5”, we unscrew the screws securing the RDT to the fuel rail.
- Using the “24” key, we unscrew the nut connecting the drain hose fitting and the RTD.
- Dismantle the fuel pressure regulator.
That, in principle, is the whole process. RTD installation is carried out in the reverse order. Important: do not lose the rubber seal that comes with the regulator. Without it, the connection of the RTD and the fuel rail will be leaky, which will lead to a change in the magnitude of the working pressure in the system.
Some useful tips
To ensure that the fuel pressure regulator does not bring you trouble and works as long as possible, use these tips.
- If you are planning to replace the RTD, buy only the original device recommended by the manufacturer.
- Pour exclusively high-quality fuel into the vehicle tank. Do not use fuel additives of unknown production.
- Do not forget to timely replace the fuel filter.
- At each MOT, check the fuel pressure in the system. If problems are identified, resolve them promptly.
- If you find problems with the regulator, do not delay with its replacement.