fuel pressure regulator failure
Content
fuel pressure regulator failure lead to the fact that the internal combustion engine starts with difficulty, has “floating” idle speed, the car loses its dynamic characteristics, sometimes fuel leaks from the fuel hoses. usually, a fuel pressure regulator (abbreviated RTD) is installed on the fuel rail and is a vacuum valve. In some vehicle models, the RTD cuts into the fuel return line of the fuel system. in order to determine that the breakdown of the fuel system is a faulty pressure regulator, you need to carry out a series of simple checks.
Where is the fuel pressure regulator
in order to find the installation location of the fuel pressure regulator, let's figure out what it is and what it is for. This will help in further searches and diagnostics.
The first thing you need to know is that there are two basic types of RTDs - mechanical (old model) and electrical (new model). In the first case, this is a vacuum valve, the task of which is to transfer excess fuel at excessive pressure back to the fuel tank through the appropriate hose. In the second, it is a fuel pressure sensor that transmits relevant information to the computer.
Usually the fuel pressure regulator is located on the fuel rail. Another option for expanding it is the fuel return hose of the power supply system. there is also an option - the location of the regulator is in the fuel tank on the pump module. In such systems, there is no fuel return hose as unnecessary. Such an implementation has several advantages, including simplification of the design (no extra pipeline), excess fuel does not enter the engine compartment, the fuel heats up less and does not evaporate as much.
How a fuel pressure regulator works
Structurally, the old-style valve (installed on gasoline cars) has its own body, inside which there is a valve, a membrane and a spring. There are three fuel outlets in the housing. Through two of them, gasoline passes through the pressure regulator, and the third output is connected to the intake manifold. At low (including idle) engine speeds, the fuel pressure in the system is low and it all goes into the engine. With an increase in speed, the corresponding pressure increases in the manifold, that is, a vacuum (vacuum) is created at the third output of the RTD, which, at a certain value, overcomes the resistance force of its spring. this creates the movement of the membrane and the opening of the valve. Accordingly, excess fuel gets access to the second outlet of the regulator and goes back to the fuel tank through the return hose. Due to the described algorithm, the fuel pressure regulator is often also called a check valve.
As for the fuel pressure sensor, it is a little more complicated. So, it consists of two parts - mechanical and electrical. The first part is a metal membrane that flexes under the force caused by the pressure in the fuel system. The thickness of the membrane depends on the pressure for which the fuel system is designed. The electrical part of the sensor consists of four strain gauges connected according to the Winston bridge scheme. Voltage is applied to them, and the more the membrane bends, the greater the output voltage from them will be. And this signal is sent to the ECU. And as a result, the electronic control unit sends the appropriate command to the pump so that it supplies only the amount of fuel needed at that moment.
Diesel engines have a slightly different fuel pressure regulator design. namely, they consist of a solenoid (coil) and a stem that rests against a ball to block the return feed. This is done for the reason that the diesel internal combustion engine vibrates very strongly during its operation, which affects the wear of the classic (gasoline) fuel regulator, that is, there is a partial and even complete compensation of hydraulic vibrations. However, its installation location is similar - in the fuel rail of the internal combustion engine. Another option is on the fuel pump housing.
Signs of a broken fuel pressure regulator
There are five basic symptoms of a fuel pressure regulator failure (both types) that can be used to judge the complete or partial failure of this important unit. Moreover, the following signs are typical for cars with both gasoline and diesel internal combustion engines. However, it is worth mentioning that the listed situations may be signs of breakdown of other engine components (fuel pump, clogged fuel filter), so it is advisable to perform a comprehensive diagnosis in order to accurately determine its performance. So, the signs of a breakdown of the fuel pressure regulator are as follows:
- Difficult starting engine. This is usually expressed in a long torsion by the starter with the accelerator pedal depressed. Moreover, this sign is characteristic under any external weather conditions.
- Engine stalls at idle. To maintain its operation, the driver must constantly gas up. Another option is when the internal combustion engine is idling, the revolutions are usually “floating”, unstable, up to the complete stop of the engine.
- Loss of power and dynamics. Simply put, the car does not "pull", especially when driving uphill and / or in a loaded state. the dynamic characteristics of the car are also lost, it accelerates poorly, that is, when you try to accelerate, there is a deep drop in revolutions at their high values.
- Fuel is leaking from the fuel lines. At the same time, replacing hoses (clamps) and other nearby elements does not help.
- Fuel overrun. Its value will depend both on the breakdown factors and on the power of the internal combustion engine.
Accordingly, if at least one of the above signs appears, additional diagnostics should be performed, including using an electronic error scanner available in the computer memory.
Fuel pressure regulator error
Fuel Pressure Regulator Diagnostic Errors
In modern cars, a fuel pressure sensor is installed as a regulator. With its partial or complete failure, one or more errors associated with this node are formed in the memory of the electronic control unit ICE. At the same time, the internal combustion engine breakdown light is activated on the dashboard.
When there is a breakdown of the DRT, then most often the driver encounters errors under the numbers p2293 and p0089. The first is called "fuel pressure regulator - mechanical failure." The second - "the fuel pressure regulator is faulty." For some car owners, when the corresponding regulator fails, errors are generated in the computer memory: p0087 “pressure measured in the fuel rail is too low in relation to the required one” or p0191 “fuel pressure regulator or pressure sensor”. The external signs of these errors are the same as the general signs of failure of the fuel pressure regulator.
You can connect to the car control unit both via Bluetooth and Wi-Fi. Scan Tool Pro having a 32-bit chip and connecting without problems, it reads and saves all sensor data not only in the internal combustion engine, but also in the gearbox, transmission, or auxiliary systems ABS, ESP, etc. it can also be used to monitor the fuel pressure readings in real time, which it transmits to the car's ECM while doing a series of checks.
Checking the fuel pressure regulator
Checking the performance of the fuel pressure regulator will depend on whether it is mechanical or electrical. old regulator gasoline ICE easy enough to check. You need to act according to the following algorithm:
- find the fuel return hose in the engine compartment;
- start the internal combustion engine and let it run for about one minute, so that it is no longer cold, but also not hot enough;
- using pliers (carefully so as not to damage it !!!) pinch the fuel return hose indicated above;
- in the event that the internal combustion engine “troiled” before this and worked poorly, and after pinching the hose it worked well, it means that it was the fuel pressure regulator that failed.
How to determine the performance on the injector
In modern injection gasoline ICEs, firstly, metal tubes are installed instead of rubber fuel hoses (due to high fuel pressure and for reliability and durability), and secondly, electrical sensors based on strain gauges are mounted.
Accordingly, checking the fuel pressure sensor comes down to checking the output voltage from the sensor when the supplied fuel pressure changes, in other words, increasing / decreasing the engine speed. Which will make it clear that the fuel pressure regulator is out of order or not.
Another method of checking is with a manometer. So, the pressure gauge is connected between the fuel hose and the fitting. Before doing this, be sure to disconnect the vacuum hose. you also first need to find out what normal fuel pressure should be in the internal combustion engine (it will differ for carburetor, injection and diesel engines). Typically, for injection ICEs, the corresponding value is in the range of approximately 2,5 ... 3,0 atmospheres.
It is necessary to start the internal combustion engine and make sure, according to the readings on the pressure gauge, that the pressure is correct. Next, you need to poke around a bit. At the same time, the pressure drops slightly (by tenths of the atmosphere). Then the pressure is restored. then you need to use the same pliers to pinch the return fuel hose, as a result of which the pressure will increase to about 2,5 ... 3,5 atmospheres. If this does not happen, the regulator is out of order. Remember that the hoses must not be pinched for a long time!
How to test for diesel
Checking the fuel pressure regulator on modern Common Rail diesel systems is limited only to measuring the internal electrical resistance of the sensor control inductive coil. In most cases, the corresponding value is in the region of 8 ohms (the exact value must be specified in additional sources - manuals). If the resistance value is obviously too low or too high, then the regulator is out of order. More detailed diagnostics is possible only in the conditions of a car service at specialized stands, where not only sensors are checked, but the entire Common Rail fuel system control system.
Causes of fuel regulator failure
In reality, there are not so many reasons why the fuel pressure regulator failed. Let's list them in order:
- Natural wear and tear. This is the most common cause of RTD failure. usually, this happens when the car runs about 100 ... 200 thousand kilometers. A mechanical breakdown of the fuel pressure regulator is expressed in the fact that the membrane loses its elasticity, the valve may wedged, and the spring weakens over time.
- Defective parts. This does not happen so often, but often marriage is occasionally found on products of domestic manufacturers. Therefore, it is advisable to buy original spare parts from imported manufacturers or check them before buying (be sure to pay attention to the warranty).
- Low-quality fuel. In domestic gasoline and diesel fuel, unfortunately, excessive presence of moisture, as well as debris and harmful chemical elements, is often allowed. Due to moisture, pockets of rust may appear on the metal elements of the regulator, which spread over time and interfere with its normal operation, for example, the spring weakens.
- Clogged fuel filter. If there is a large amount of debris in the fuel system, it will lead to clogging, including the RTD. Most often, in such cases, the valve begins to wedge, or the spring wears out.
usually, if the fuel pressure regulator is faulty, then it is not repaired, but replaced with a new one. However, before throwing it away, in some cases (especially if it is), you can try to clean the RTD.
Cleaning the fuel regulator
Before replacing it with a new similar element, you can try to clean it, since this procedure is simple and accessible to almost every car owner in garage conditions. Often, special carburetor cleaners or carb cleaners are used for this (some drivers use the well-known WD-40 tool for similar purposes).
Most often (and most accessible) is to clean the filter mesh, which is located on the outlet fitting of the fuel pressure regulator. Through it, fuel is supplied precisely to the fuel rail. Over time, it becomes clogged (especially if low-quality fuel with mechanical impurities, debris is regularly poured into the car tank), which leads to a decrease in the throughput of both the regulator and the entire fuel system as a whole.
Accordingly, in order to clean it, you need to dismantle the fuel pressure regulator, disassemble it, and use a cleaner to get rid of deposits both on the grid and inside the regulator housing (if possible).
Dirty fuel regulator screen
After cleaning the mesh and regulator body, it is advisable to force-dry them with an air compressor before installation. If there is no compressor, place them in a well-ventilated warm room for a time sufficient to completely evaporate moisture from their outer and inner surfaces.
also one exotic cleaning option is the use of an ultrasonic installation at a car service. namely, they are used for high-quality cleaning of nozzles. Ultrasound can "wash" small, strongly ingrained, pollution. However, here it is worth weighing the cost of the cleaning procedure and the price of a new mesh or fuel pressure regulator as a whole.
