DIY fuel pressure regulator repair

Found on the Internet. I think many will come in handy!
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Now I will quote as it is.

homemade adjustable fuel regulator

and so what we are talking about is clear from the title of the topic, the fuel pressure regulator. it all started when my own pump began to die, I bought another from a turbo chayzer and installed, to my surprise, he began to swing 2.7 at idle instead of the prescribed 2.5 and eat benz 25 instead of 15 to solve the problem it was possible in several ways to buy an inexpensive China adjustable regulator, buy a branded Japanese regulator or make it yourself, with the Chinese for about five years on the back there was an experience how I did not grind its valve to keep the pressure, he did not want to drain everything into the return line and did not want to step on this rake again, I haven’t dealt with brand regulators and cannot have for financial reasons, there is only one thing to do myself, I take the regular regulator as a basis

I cut off the top of it

smooth the edges

then the most interesting thing is to take what is left of the regulator and go to the turner so that he makes a new upper part of the regulator



I cut off the vacuum tube from the top of the regulator, this will be an emphasis under the spring


a six-bolt will be our stem, the tip will be narrowed

to put our emphasis on it under the spring

on the side I drill a hole for the vacuum tube and solder it with brass

I screw in the adjusting bolt and put the stop under the spring on it and screw it up slightly so that the stop does not come off and turn easily

I put on a gasket on my own regulator


and start assembling

painting

the product is ready

so everything related to the fuel part, that is, the valve itself, the membrane remained native with Japanese quality, we did not climb there and there are no problems like the Chinese regulator, you can lower the adjustments very decent to 2 and raise to 5, set the required 2.5 and lo and behold the car began to eat put 15 liters smooth idling and even the smell from the exhaust has changed, everyone will be happy if my notes will help someone

The fuel line and the ramp of the injector feeding the engine injectors operate at a pressure of about 3 bar. Since the electric pump is engaged in the supply of gasoline, a special valve is involved in the system to limit the pressure of the fuel. Otherwise, the sprayers will start leaking, and the motor will choke with the over-enriched mixture. To avoid problems with fuel supply, you need to timely diagnose the signs of a malfunction of the fuel pressure regulator (abbreviated as RTD) and know how to fix it.

The fuel supply system of most passenger cars provides for the continuous operation of an electric petrol pump. It constantly pumps gasoline into the fuel line and rail, raising the pressure to the maximum (5–7 bar, depending on the car brand). But such performance is needed only with increased load on the engine, when it develops high revs and consumes a lot of combustible mixture. In normal operation, a fuel pressure of 3–3.5 bar is sufficient on the injectors.

The fuel pressure diaphragm valve, installed in the engine power system after the fuel pump, performs 3 main functions:

1. Limits the pressure of the fuel in the line at low engine loads, dumping the excess back into the tank through a separate pipe.
2. When the consumption of gasoline by the power unit increases, the return flow is partially or completely blocked by the regulator.In this way, the valve maintains the minimum pressure required for the normal operation of the motor.
3. Maintaining pressure for a long time after stopping the power unit.

Without the RTD, the pump would "push through" the locking mechanisms of the injectors and gasoline flowed into the cylinders uncontrollably. In addition, the regulator protects the line from leaks at the connections, which will inevitably appear from the effects of strong pressure.

The valve design and principle of operation depend on the type of fuel system of a particular vehicle. There are 3 ways to supply gasoline from the tank to the injectors:

1. The pump together with the regulator is installed inside the tank, the fuel is supplied to the engine through one line.
2. Gasoline is supplied through one tube and returned through the other. The fuel system check valve is located on the rail.
3. The circuit without a mechanical regulator provides for the electronic control of the fuel pump directly. The system has a special sensor that records the pressure, the pump performance is regulated by the controller.

In the first case, the return flow is very short, since the valve and the electric pump are interlocked into a single unit. The RTD, located immediately after the supercharger, dumps excess gasoline into the tank, and the required pressure is maintained in the entire supply line.

Reference. The first scheme with a regulator inside the gas tank has been introduced on all Russian-made VAZ cars.

The second option is used in most foreign cars. A valve built into the fuel rail bypasses excess fuel to the return line leading to the tank. That is, 2 gasoline pipes are laid to the power unit.

It makes no sense to consider the third circuit - instead of a regulator, there is a sensor, whose performance is checked using a computer connected to the diagnostic connector.

A simple fuel pressure valve installed in the fuel pump unit consists of the following elements:

• cylindrical body with branch pipes for connecting the supply and return lines;
• diaphragm connected to the locking rod;
• valve seat;
• spring.

The amount of pressure in the supply line depends on the elasticity of the spring... While most of the fuel goes into the cylinders (high engine load), it keeps the diaphragm and valve stem closed. When the crankshaft speed and gasoline consumption decrease, the pressure in the network increases, the spring is compressed and the diaphragm opens the valve. The fuel is dumped into the return line, and from there into the gas tank.

The fuel pressure regulator installed in the rail works in a similar way, but responds more quickly to changes in load and gas mileage. This is facilitated by the connection of an additional element pipe to the intake manifold. The higher the crankshaft revolutions and the vacuum from the spring side, the more the diaphragm presses the rod down and closes the fuel passage to the return line. When the load decreases and the revolutions fall, the vacuum decreases and the rod releases - the flow to the return line opens and the excess gasoline is discharged into the tank.

During the operation of the machine, a motorist may encounter two types of RTD breakdown:

1. The pressure drop in the rail is below the permissible level - the regulator directs most of the fuel through the return line to the gas tank.
2. The increase in pressure to the maximum - the element does not allow fuel to flow into the return line.

Note. As a rule, the first malfunction is accompanied by a rapid drop in pressure in the system after turning off the electric petrol pump.

It is quite simple to trace the signs of the first malfunction - the power unit is sorely lacking fuel for normal operation in all modes. Symptoms appear as follows:

• cold start is difficult, the engine is extremely unstable until it warms up;
• "Dips" in the process of acceleration and jerks when moving uphill;
• the car often stalls at idle;
• petrol consumption increases per 100 km.

The increased fuel consumption is due to the actions of the driver trying to compensate for the lack of a combustible mixture by pressing the accelerator pedal. It is rather difficult to drive in this mode - it is better to check the fuel pressure regulator for operability without delay.

When the valve does not let excess fuel into the tank, the following consequences are observed:

1. Due to too high a pressure from the side of the rail, the injectors begin to leak and fill the cylinders with clean gasoline, and not with a working air-fuel mixture.
2. The engine does not start well "hot", throws out black smoke from the exhaust, sometimes pops are heard in the exhaust manifold. The reason is flashes of unburned fuel.
3. Consumption increases noticeably.
4. Leaks can be observed at the joints of the fuel pipes, and a sharp gasoline smell is felt.

Practical experience shows that the lack of a fuel mixture is manifested more often than an overabundance. That is, the most common RTD malfunction is the discharge of gasoline into the return pipe and tank.

If the above signs are found, you should check the performance of the RTD in one of the following ways:

• measure the pressure in the fuel rail, its value must be at least 3 bar;
• find the return hose and carefully pass it with pliers on the running engine;
• disconnect the vacuum tube from the manifold from the regulator.

The most reliable way is to measure with a pressure gauge. The device is connected to the union on the fuel rail, the check is performed with the engine running. If the pressure is below 3 bar, check the fuel pump additionally - the unit may have lost performance. For diagnostics, you will need a tee with a pressure gauge cut into the supply line. If the pump gives 3 bar or more, change the RTD.

The reasons for the loss of valve performance are as follows:

• the spring has lost its elasticity and allows the membrane to bypass fuel at a low head;
• contamination with low-quality gasoline;
• jamming of the stem.

Due to the design features (the body of the element is seamed), repair of the fuel pressure regulator in most cases is impossible, the part will have to be changed. The flush and purge option only helps with blockages inside the element.

Squeezing the return line is done at idle speed of the engine, preferably “cold”. If the engine has stabilized, there is a problem with the RTD or pump. To determine the culprit, you still need to measure the supply pressure. Try to remove the vacuum tube from the manifold at high speeds - if the valve becomes unusable, the behavior of the power unit will not change.

Hello to all readers. I'll start with the background. It seemed to me that the car had lost its former agility. Of course, I was puzzled by this problem, but the search for it was extremely delayed. And when he arrived at the garage somehow, he decided to measure the fuel pressure. It turned out to be 2 points, realizing that even for a 1.5 liter engine this is not enough, at a rate of 2.8.

I started digging. I squeezed the return line and realized that the fuel pump was dying, it was pressing 3kg maximum. I turned off all further examinations on this and resigned myself to buying a new pump. The next day at work I found out that a friend has a working pump, which he does not need)) He presented it to me free of charge, for which many thanks to him. On the weekend I went to put it.

I replaced the pump, well, I think it will trample now)) And there is a shish)) Again 2 points) I squeeze the return line, 5 kg is the norm. So it’s not in vain)) And the logical chain leads to the fuel pressure regulator, which will be discussed later))
I didn't want to change it, because he kept the pressure when the pump was turned off. And new regulators come across even worse)) The question arose of how to raise the pressure. In the junk (all the same it came in handy), I found a regulator that had been bought and turned out to be defective (do not lose checks) lay and waited in the wings.I decided to see how it works (pictures are pictures, but live better) sawed it

here it is
Looking at the insides, it became clear that it was necessary to tighten the spring. How to do it? Easy)) you need to jam the case. Decided to work locally

there he is
Picked up the phone and the hammer

and light blows (there were 3 of them) crushed the body, checking the pressure after each blow

I raised it to 2.5-2.7 and did not become greedy, otherwise I would have to break my head how to pull it back. And in general, everything, the car went, the jerks were gone, the appetite decreased - beauty. Someone will think -Kolkhoz, but cheap. Thank you for your attention, I hope someone will be useful and help.

Author; Alexey Bor, Nizhny Novgorod region

The fuel pressure regulator (RTD) is a diaphragm valve that is pressurized with fuel on one side and the intake manifold springs on the other. When the speed decreases, the valve opens, as a result of which the remaining fuel is drained from the engine into the tank. When fuel is needed again, the fuel pump starts, passing fluid through the filter. Further along the chain is a regulator mounted on the fuel rail, which ensures that the correct pressure in the system is maintained throughout the entire process.

It looks like a RDT VAZ 2110

It is in maintaining a constant pressure in engines with fuel recirculation that the work of an RTD is. In the absence of a system for returning unused fuel to the tank, a pressure regulator is still required, but in this case the pressure will vary depending on the duration of the injection.

A faulty regulator can create certain difficulties for the normal functioning of the engine. Low pressure in the fuel system does not provide the power unit with a sufficient amount of fuel, as a result of which a drop in power and unstable engine operation are inevitable. Excessive pressure is also dangerous - a break in the fuel hose or flooding of injectors cannot be classified as minor breakdowns.

Often it is the fuel pressure regulator that is the cause of such malfunctions, so they need to be eliminated as soon as they are discovered, without waiting for the next inspection or failure of more serious and expensive engine elements.

Failure of the fuel pressure regulator is always accompanied by fairly characteristic symptoms, and quite obvious ones. The following symptoms can indicate the occurrence of an RTD malfunction:

• uneven engine;
• stalling engine at idle and poor reaction to pressing the accelerator;
• a noticeable decrease in power and dynamics;
• feeling of "choking" engine when driving;
• overestimated fuel consumption;
• leaking fuel lines even when the clamps are fully tightened.

The mechanical design of an RTD implies its failure on a completely understandable basis. Most often, a regulator malfunction occurs for the following reasons:

1. Weakening of the valve and the resulting lack of pressure. The valve is installed on a spring, which tends to sink over time, thereby passing fuel into the tank constantly. The engine runs out of fuel and simply cannot deliver the power it needs.

2. Obstacles to the movement of fuel. This is the opposite situation to the previous one: in this case, the valve interferes with the movement of the fuel or completely blocks its passage to the power unit. In this case, the engine can stall at any time, and fuel will begin to leave the system through any available openings.

3. Wedging of the valve. Usually, such a "disease" becomes noticeable during acceleration - the car starts to jerk, and the engine power drops and rises abruptly.

As a rule, the occurrence of malfunctions in the fuel pressure regulator occurs due to mechanical damage, for example, deterioration of elements or their clogging. Regardless of the cause of the malfunction, the element will have to be changed - the fuel pressure regulator cannot be repaired.

Sometimes the appearance of problems is not related to the regulator itself, but is very closely related to its operation. For example, when using poor fuel or neglecting the timely technical inspection of the car, malfunctions may occur, including those related to the functioning of the fuel system.

The fuel pressure regulator is a purely mechanical element, therefore it is impossible to check its performance using electrical devices. In addition, it is worth noting the fact that RTD is not a collapsible element, therefore, if a malfunction is found in it, the only way out is to replace it. Such repairs will not hurt the wallet - regulators are quite cheap, and repairs (if possible) would have cost much more.

To bring the car to normal condition, it is necessary to check the RTD for operability. There are several simple methods that allow you to independently determine the causes of problems and eliminate them without resorting to expensive specialist services.

The first way is visual. It can only be used on carburetor engines, so this method is practically not used today. Such a check consists in the following: it is necessary to pinch or disconnect the valve and observe the flow of fuel. The malfunction is determined by the intensity of the fuel jet. The method is far from the most effective, it is not able to provide the required accuracy, therefore it is not recommended to use it.

The second method gives an accurate result and allows you to speak with confidence about an RTD malfunction.

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To check, you need a pressure gauge, which must be installed in the gap between the fitting and the fuel supply hose by disconnecting the vacuum hose. When checking, the pressure should rise from 0.3 to 0.7 bar. The absence of a pressure increase during such a check does not mean anything, and the operation must be repeated with another vacuum hose. If, in this case, the regulator does not produce pressure, then it is clearly faulty and requires replacement.

By connecting a pressure gauge to the fuel system, you can use another test method: simply pinch the hose that returns unused fuel to the tank. The needle of the manometer must necessarily respond to such treatment. Naturally, this method is not suitable for testing fuel systems that use metal pipes or hoses that are too short.

The same method allows you to identify a RTD malfunction without using a pressure gauge if the engine does not develop normal speed. Having pinched the return flow when the engine is running, it is necessary to track the speed and listen to the engine - if its work has leveled off, then the problem lies in the faulty regulator valve, and it needs to be changed.