Fuel pressure is an important parameter that must be constantly monitored. Its value directly affects the efficiency of the motor, its power and behavior in various modes. Consequently, every car owner who cares about the technical condition of his own car should periodically check the pressure. How to do this, read further in the article.
Fuel injector rail
The fuel rail (rail) is a mandatory element of the fuel system of an internal combustion engine with distributed injection. It is a section of a hollow tube, the ends of which are closed on both sides and are distinguished by the presence of bends for connecting tubes of smaller diameter. Through these tubes, fuel flows to the nozzles that are located on it. In addition, there is a pressure regulator on it. The fuel that enters the ramp is moved through injectors into the intake pipe. In addition to the outlet pipes, this design also contains a shut-off fitting and a hole.
How to check the pressure in the fuel rail, methods of checking
This parameter can be measured using several methods. One of the most common is the purchase of a special kit, which includes a special adapter for connection, a pressure gauge (it is thanks to this that the measurement is carried out) and a drain. You will have to allocate approximately 1,500 rubles to purchase these devices. But you can do it differently - go to a service station, where specialists cost 300-500 rubles. will carry out the required measurements.
However, there is a more sophisticated method that does not require additional costs - you can measure fuel pressure using an ordinary pressure gauge used to check tire pressure. In this case, it is advisable to use pressure gauges for measurements, the limit of which is minimal (about 6-7 atmospheres). This will reduce the error to a minimum.
How to check the fuel pressure of a VAZ 2110 1.6 engine without return flow, check diagram (step by step)
On a VAZ 2110 with a volume of 1.6, the pressure indicators in the fuel rail are unchanged and vary between 3.6-4 bars. In this case, measurements are often carried out according to the same principles as described above. However, there are several other non-standard methods.
- We prepare the above-described structure - a hose at the end with a pressure gauge.
- The diameter of the hose should be approximately 8 millimeters.
- Measurements are taken at the outlet of the fuel pump module.
- The normal parameter is considered to be a pressure of 5-7 atmospheres.
- Remember how the return line is closed on engines with a drain ramp. In this case, it is better to turn off directly at the fuel pump.
- The double hose should be dismantled and a plug inserted (instead of the plug, you can use a “nipple” from the fuel filter).
- Pull the single pipe onto the pump fitting. Measurements are taken directly on the ramp.
It is important to remember that problems with the fuel system, as a rule, manifest themselves as sudden “dips” when reaching high engine speeds. In addition, when driving, the car can jerk, it stalls when accelerating, and so on. In this case, you need to check the pressure. Only after this can the main causes of the problems be discovered - the fuel pump, injectors, filters, and so on.
If the electrical circuit in a VAZ 2110-2112-2170 car is obviously in good working order, and the pump hums as usual, this does not mean that gasoline is supplied to the injectors as normal. No! There may be some problems here. Let's start with the most basic.
First, remove the protective cap of the fitting (as shown in photo 1), be sure to place a cloth underneath so as not to splash the engine compartment with fuel, and use the tip of a thin slotted screwdriver to press the spool of the fitting. If the stream of fuel is thin or weak, this means low pressure in the fuel rail; you need to look for the cause. If gasoline sprays with strong pressure, then there is hope that the pressure is within normal limits (2.8-3.2 bar), but to be sure, you need to measure it with a pressure gauge. At the service center this is done using fuel pressure gauges with adapters.
We will use a simple one from a tire pump. The only main thing is that the measurement limit is at least 4 bar. You will also need a part of a gas-resistant hose, the length of which should be 150 millimeters, the internal diameter of which should be 10-12 mm. , as well as 2 more clamps. Use the wheel valve cap to unscrew the spool valve from the fuel rail fitting. We put the pressure gauge hose on the fitting and tighten it with a clamp.
Fuel pump repair
To replace or repair the pump, it will need to be removed from the engine. Tools you will need:
- 13 mm wrench;
- crosshead screwdriver.
Removing the fuel pump
We dismantle the unit in the following order:
- Wipe the pump with a rag.
- Disconnect both hoses (inlet and outlet) by loosening the clamps with a screwdriver.
- We pull the hoses from the fittings.
If you need to replace the rod, then simply remove it from the heat-insulating spacer and replace it with a new one.
Once a situation arose on my car when engine oil was leaking from the installation site of the fuel pump (in the area of the gaskets). It was not immediately possible to identify the cause. At first I made mistakes on the gaskets between the engine block and the spacer, as well as between it and the fuel pump. I replaced them, but did not achieve a positive result. After dismantling the mechanism again, I examined all the elements more carefully and discovered that the heat-insulating spacer had a crack through which oil was leaking. I had to replace it, after which the problem disappeared. In addition to the described case, there was a similar situation when oil was leaking at the location of the fuel pump. This time the pump itself turned out to be the culprit: oil was oozing from under the axis of the manual fuel pumping lever. There were two options to get out of the situation: accept it or buy a new product. I bought and installed a new pump (DAAZ), which to this day works properly and does not leak.
Disassembly
To disassemble the fuel pump you need to prepare:
- 8 and 10 mm wrench;
- Phillips screwdriver.
The disassembly procedure is as follows:
- Unscrew the bolt holding the top cover.
During assembly, the strainer must be installed so that its hole is above the valve.
Replacing valves
The VAZ 2107 fuel pump valves are included in the repair kit. To replace them, you will need a needle file and suitable attachments for dismantling.
The disassembly sequence is as follows:
- We remove the cores using a needle file.
Installing and adjusting the fuel pump
Installation of the fuel pump on the “seven” is carried out in the reverse order of removal. The process itself does not cause any difficulties. However, attention should be paid to the gaskets, since their thickness has a direct impact on the operation of the mechanism.
Adjustment of the position of the unit must be carried out if, after its removal, the gaskets were replaced or the old seals were strongly pressed in.
The fuel pump is sealed with several gaskets:
- adjustable (thickness 0.7–0.8 mm or 1.1–1.3 mm);
- thermal insulation;
- sealing (0.27–0.33 mm).
The adjusting and sealing gaskets differ only in thickness. There must always be a sealing gasket between the engine block and the heat-insulating element.
The fuel pump is adjusted as follows:
- Install the sealing gasket.
Video: how to adjust the fuel pump on a “classic”
Signs of breakdown
If for some reason the fuel pressure regulator does not perform its functions, then this can be understood by the following signs:
- The engine's operation has become unstable, it may begin to stall when idling, although it would seem that the fuel level is sufficient and all systems are in working order;
- The crankshaft at idle speed has increased or, conversely, decreased speed;
- The engine, as they say, “loses throttle response”;
- While driving, dips and jerks occur in a running engine;
- Gasoline consumption increases compared to what it was before;
- The content of CO and CH in the exhaust increases;
- The engine starts with difficulty. Although this property does not always appear.
If the regulator has become completely unusable, then an increase in fuel pressure is observed. Instead of the norm for the VAZ 2110, which ranges from 2.5 to 3.3 kg/cm2, it reaches 4 – 5 and even more.
Consequently, the fuel pump supplies more gasoline by volume, which is not completely burned, and overconsumption is guaranteed. Of course, such a regulator needs replacement, and the sooner the better.
If the fuel pressure regulator does not provide the required pressure, or simply does not hold, then the lack of fuel pressure leads to the fact that normal supply does not occur, and the VAZ 2110 “chokes” when you need to increase the speed.
In addition, the starter cannot quickly spin the engine; it has to be turned on many times.
Fuel pump drive
The VAZ 2107 fuel pump operates from a pusher (rod) and an eccentric located on the shaft of auxiliary devices (“piglet”, intermediate shaft), which is driven by the timing mechanism through a gear. Auxiliary devices include distributor, oil and fuel pumps.
Operating principle
The drive works as follows:
- the intermediate shaft rotates via a timing chain;
- the eccentric acts on the rod and pushes it;
- the rod presses the fuel pump lever, ensuring its operation.
Fuel pump drive malfunctions
As the fuel supply unit wears out, problems may occur that affect the performance of the latter.
Rod wear
The main sign of a worn-out rod is that the car does not reach the required speed. If the car accelerates, but, having gained speed to a certain value, does not develop it anymore, the reason is precisely the wear of the rod. Recently, the pusher has been made from such low-quality metal that it leads to wear out literally after 500–1000 km. The edge of the rod on the eccentric side is simply flattened, which indicates the need to replace the part.
The fuel pump rod should be 82.5 mm long.
FLS
It is quite clear that we first learn about excessive consumption of gasoline by readings from the level sensor. However, sometimes the FLS also starts to lie, and then the true consumption cannot be known.
There may be a situation when you still have half a tank of gasoline, but the FLS says that the fuel is almost empty. That is, the flow sensor itself may confuse you, and before rushing to replace the regulator, make sure that the FLS is working properly, remember that the VAZ 2110 has problems with it very often.
If you notice that it is lying, the fuel sensor may need adjustment or even replacement.
