The car is jerking! The robot twitches on the Ford Focus 3.

Ford Focus 3. Engine valve noise

Engine valves knock: causes and troubleshooting

No matter how reliable the car is, the time comes and you are forced to go to the service station to diagnose and repair faults. At the same time, most of the breakdowns can be fixed with your own hands, but there are also those that only professionals can help to eliminate. Valve knock is a common problem that falls somewhere in between in terms of difficulty. In some cases, it is possible to identify a malfunction and make repairs on your own, while in others you have to contact the master for help.

How to diagnose a knock

Without sufficient experience, it is sometimes difficult for car owners to identify the problem by ear. This is not surprising, because anything can be a source of extraneous noise - a crankshaft, bearings, a faulty belt and valves. But unlike other sounds, the knock of valves gives itself out as a characteristic sonority, with a certain metallic tapping, near the gas distribution mechanism. In addition, unusual noise occurs, regardless of the engine speed.

It is not difficult in practice to recognize that valves are knocking, but sometimes even car owners with experience fail to diagnose their malfunction. But to confirm or refute suspicions, you can make a diagnosis yourself. For this:

Raise the hood, then unscrew the cap from the engine filler hole (through which oil flows).
-Listen to the operation of the motor. If the volume of the sound increases, the valves are the cause of the problem.
-Place a stethoscope near the part you suspect is malfunctioning. With this device, you can accurately determine the cause of extraneous noise.

Reasons for knocking

Valve knocking can be caused by many reasons, each of which deserves special attention. Please note that all machines are equipped with camshaft(in the upper part of the engine), and the operation of the valves is provided by the elements of this assembly - rods or, in other words, pushers.

So why are the valves knocking? Let's highlight the main reasons:

Changing the gap between valves and pushers. When the car is released, the distance between the rods and valves is fine-tuned. If the parameter deviates from the norm (decrease or increase), a “metallic” tapping appears.
- Filling the car with low-quality fuel. In the case of using bad fuel, engine detonation occurs, which also affects the valves.
- Lack of oil pressure during acceleration. There are situations when the knock of the valves appears only when driving at high speed or at the moment of acceleration. The reason is insufficient pressure in the engine lubrication system to increase the speed.
-Incorrect installation or misaligned position of the timing belt (how to set marks and tighten the timing belt).
-Natural wear and tear. If valves are knocking on your car, this often indicates a banal deterioration of the part and the need to replace it.

Why there is a knock of valves on a cold engine

When checking, pay attention to one of the main parameters - the temperature of the engine. There are situations when an extraneous sound appears only on a cold or hot engine. If you "bind" the knock of the valves to this parameter, you can draw additional conclusions. So, if an extraneous sound appears only on a cold engine, then the reasons are as follows:

Narrowing of the valves. It is no secret that, in the process of heating, the metal tends to increase in volume, and when cooled, it decreases. For this reason, the distance between the valves (on a cold engine) can be small, and after the engine reaches operating temperature, it returns to the factory setting.
Motor wear. The second reason why valves knock is the deterioration of the engine itself.
It turns out that the gap between the valves and the rods does not correspond to the parameter set at the factory, but this only manifests itself on a cold engine. As soon as the engine warms up, the problem disappears.

Why do valves knock on a hot engine

If the problem manifests itself even after warming up, the reasons may be the following:

Lack of oil in the reservoir.
- Dirty oil filter.
-Insufficient broach of the camshaft mounting bolts to the bed.

In addition, extraneous sound can be caused not only by the sound of valves, but also by hydraulic compensators.

How to adjust valve clearances

The easiest and fastest solution to the problem is to go to the service station and instruct the elimination extraneous sounds professionals. But, unfortunately, financial opportunities do not always allow such a luxury, and you have to solve problems with your own hands. There are other situations when the car owner is interested in messing with the car, and personally gain experience in repair.

If you find that the valves in the engine are knocking and decide to fix the problem yourself, get ready for some serious work. One mistake is enough, and the sound will become even louder. That is why, for the elimination of knocking, you should not take on a novice car owner. It is important to clearly know the sequence of actions, and follow it. To avoid mistakes, read the auto repair manual. A brief algorithm is given below:

Drain the engine oil.
- Remove the cylinder head plug. This is necessary to gain access to the valves.
-Rotate the camshaft so that the mark on the pulley aligns with the setting lug.
-Gap between valves and rods determine by touch. At the same time, change the distance using the adjusting washer.
-Roll the washer a certain number of times (it all depends on the make and modification of the car).
- Replace all the parts, then check whether the knock of the valves has been eliminated or not.

If, after the work carried out, the problem has not been resolved, head to the service station and give the car into the hands of the masters. In such a situation, it is unlikely that you will be able to adjust the gap with your own hands. There are situations when other breakdowns are the cause of extraneous noise. But it cannot be ruled out that the previous adjustment was performed incorrectly.

Hello!

lexa264
Your problem is the same as mine. It all just started somewhere 1500 km before TO-1 (on a run of 12500). On TO-1, all the filters were changed, everything was checked, looked at, lubricated where necessary ... All MOT took place in my personal presence. No crime was found.

I will describe in more detail what is happening on my car (FF3 1.6 PS 125 hp Trend Sport sedan, currently mileage 14500).
1. The first 20-30 km of the trip after a normal overnight stop - everything is perfect (starts off smoothly, drives smoothly, nothing crunches / creaks, etc.)
2. Then it starts:
- I smoothly move off after the traffic light (provided: if the traffic light is short for about 10s, then I leave the box in D and hold the brake, if the traffic light is long, 15-30c I switch the box to N and hold the brake, or put it in P if I keep the pedal on the crowbar slope)
- I feel that vibration starts in the nose of the car
- at the same time, the car does not jerk back and forth, it’s just that a certain wave starts to go along the body
- approximately at the transition from 1st to 2nd gear, the vibration becomes very noticeable, the steering wheel is already shaking and the passengers in the car feel
- then the vibration wave, as it were, passes into the center of the car, weakens a little and, finally, shuddering again perceptibly (approximately the transition from 2nd to 3rd gear), fades with further acceleration somewhere in the area of ​​\u200b\u200bthe box
3. I emphasize that with all this the car moves smoothly, i.e. it feels like it just sausages from some incomprehensible vibration, but it doesn’t twitch back and forth, it seems to go evenly
4. At the same time, metal clanging seems to be inaudible
4. More features:
- if you start off sooooooooo smoothly, well, literally press the gas pedal quite a millimeter, then there is NO vibration (well, or quite insignificant, which indicates that the engine is straining and starting to accelerate)
- if you sink the slipper into the floor, then there is almost NO vibration either
- it happens that the vibration disappears COMPLETELY, even if you do not monitor the position of the gas pedal at the time of acceleration

That is, if you add everything together, then the conclusions are as follows:
- the car vibrates noticeably during acceleration, but does not twitch back and forth, it drives evenly forward
- this only happens when the car is warm enough.
- there is a certain resonance at a certain position of the gas pedal, which significantly sausages the car
- it rolls from time to time, i.e. The error does not always show up.

After reading all the topics about vibrations and so on, I figured out the possible options:
- engine mounts are unlikely, because otherwise, the symptoms would not have appeared on a warm car (although maybe I'm wrong?)
- I don’t sin on the box, I looked at everything, it’s dry at the junction with the engine, the firmware is fresh (just in case, they reloaded it, but nothing has changed); a photo:
- here at the joints, too, nothing seems to flow; a photo: ,

Here is such information, comrades! I would like to hear what anyone thinks about this, otherwise I already broke my head, trying to determine the jamb myself. Of course, I’ll go to the dealer, but as practice shows, it’s better to tell them what the problem could be, and a lot of time and money will be lost from it.

P.S. probably later I will make a detailed report on the passage of TO-1 and throw here a link to the topic
P.P.S. I apologize for the sea of ​​text, all the best!

In relation to a car, a jerk is a short-term spontaneous change in the speed of rotation crankshaft engine regardless of the position of the accelerator pedal. In daily operation, as a rule, there are a series of jerks. The limiting case of a jerk (failure) is a perceptible delay in the response of the engine to pressing the accelerator pedal.

Conventionally, three types of jerks can be distinguished:

At the moment of the beginning of the movement;

When accelerating;

With steady motion, i.e. at a constant position of the accelerator pedal.

To determine the causes of jerks when driving a car with an injection engine, special diagnostic equipment is required, so we recommend contacting a service that specializes in repairing fuel injection systems. However, as practice shows, in most cases, jerks are caused by insufficient fuel pressure in the fuel rail or a malfunction of the position sensor. throttle valve built into the cover of the throttle assembly. Besides specific reason car jerking Ford Focus 3, equipped with a system electronic control throttle assembly, there may be a malfunction of the accelerator pedal.

With some skills, the cause of jerks can be determined independently.
At the moment of the beginning of the movement, the limiting case of a jerk, a failure, most often takes place. The most unpleasant sensations are associated precisely with the delay in the response of the engine to pressing the accelerator pedal. Sometimes the engine even stalls. A jerk occurs at the moment the throttle valve starts to open, when, according to the signal from the throttle position sensor, the ECU determines the moment of transition from the mode idle move to the load mode and should increase the amount of fuel supplied through the nozzles. With insufficient pressure in the fuel rail, even with an increase in the injection duration, there is not enough fuel for a smooth start.

In addition, a jerk can also occur due to a malfunction of the electromechanical part of the throttle assembly and contamination of the throttle valve with deposits from crankcase gases.

The cause of jerks during acceleration can be, as in the previous case, insufficient pressure fuel in the fuel rail. The electronic unit engine control, having received a signal from the throttle position sensor about the intensive opening of the damper at a large angle, it seeks to maximize the fuel supply, but due to the reduced fuel pressure it is not able to do this.

In addition to these reasons, jerks when accelerating a car with robotic box gears can be caused both by an insufficient amount of working fluid in the box, and by a malfunction of the box itself.

Jerks when driving Ford Focus 3

Such jerks are most often caused by a malfunction of the ignition system. Diagnosis and repair required. On the way, you can try to do the following yourself:

Take a close look engine compartment. Switch off the ignition and check that all wires and connectors at the ignition coil and high voltage wires are securely fastened and seated. Start the engine and listen to its work: the crackling during the breakdown of the high voltage current to ground is weak, but distinct. In complete darkness, a spark is clearly visible during breakdown;

Replace spark plugs regardless of their condition and mileage. Pay attention to the condition of the candles: if it is not up to standard, it may be necessary to repair the engine or its systems.
A specific cause of jerks in steady motion ford car Focus 3 may be a failure of the throttle position sensor built into the throttle assembly cover.

Additional symptoms confirming the malfunction of this sensor:

Uneven engine idling;

Reduced maximum engine power.

The throttle assembly cover is non-separable, so it is not repairable. If a sensor malfunction is detected, replace the throttle assembly with cover.

Ford Focus 3. Steam comes out from under the cap of the expansion tank (white smoke)

Breakdown of the cylinder head gasket

The most common answer to such a problem is the cylinder head gasket (cylinder head) burnt out, if it is not difficult for you to disassemble the engine, the first thought would be to change this gasket. But imagine that there are two more reasons for the antifreeze to be squeezed out of the system.

1- This airlock in the coolant system, because of it, not only the stove in the cabin may not work, but this is already a sign of a plug in the coolant - coolant, provided that your fluid level is normal, but the thermostat may not work correctly. Which can lead to an increase in pressure in the cooling system. Well, squeezing out antifreeze.

2- This is a problem associated with the expansion tank, well, and the smart lid of this tank.

To improve the circulation of coolant through the engine system, when the engine is started, a slight pressure is created by the pump, which increases the efficiency of the cooling system. If insufficient pressure is created in the coolant system, the engine will heat up faster. Which can lead to boiling or decomposition of antifreeze. When boiling, the decomposition of antifreeze vapors are looking for weak spots. Such as wooden rubber o-rings of the cooling system, bad pipes, the cap of the expansion tank or radiator is not tightened tightly.

The cylinder head is, of course, also not a secondary problem, but it is also quite possible to diagnose it, and as it turned out, it was very simple.

We start the engine, open the cover of the expansion tank, if on idling you can see bubbles coming from the main hose, this is one of two things, either an air lock breaks, or a problem with the cylinder head gasket.

If this is an air lock, then after gasping and waiting for some time, you can get rid of it, the most effective procedure is very difficult to describe, since you need to carry out a series of sequential actions and it is better to show them on camera.

If there is no plug and there is a problem with the cylinder head, then you will have constant or weak seething in the expansion barrel or the antifreeze level will gradually go away.
If your coolant goes somewhere and there are no traces on the engine, then there may be coolant either in the cylinder or in the muffler, which also often happens. This indicates a problem with the cylinder head.

Expansion tank malfunctions

First, be sure to look at the smudges of antifreeze on the barrel, there are three problems with it:

1- the cover of the expansion tank (the cover gasket is hardened) allows air to pass through, there is also a deformation of the cover of the RB - the expansion tank - only a replacement for the original.

2- the expansion tank cap thread is broken, in this case a new cap will not help for a long time!

3- the expansion barrel has a leak or burst along the seam, which manifests itself from an increase in pressure in the engine coolant system, there are such cases that as internal combustion engine cooling the gap is joined and the coolant stops squeezing out.

4- air leak (sometimes, but rarely)

Most importantly, this is a visual inspection for both leaks and damage to the hoses.

Pay attention to the thread on which the tank cap was twisted.

It so happens that if you tighten the cap, it rises crookedly and the liquid easily comes out of the tank. If you look at the thread of the tank, it’s not really clear whether it’s whole or not, but if you highlight it on one side, it’s all torn off.

Other reasons

1. A white emulsion (foam) on the oil level dipstick or on the oil filler cap indicates that coolant has entered the lubrication system, most likely through a hole in the cylinder head gasket. Sometimes, though rarely, the gasket is safe and sound, and the leak is due to a crack in the block itself. But in any case, if there is a white emulsion in the lubrication system, you need to sound the alarm, or even better, pick up a tool and fix the problem.

2. White smoke from exhaust pipe when the engine is running, indicates that coolant has entered the engine cylinder(s). At the same time, its level decreases, since it partially “flies into the pipe”. The exhaust of a car can be white when the engine is warming up, there is a large amount of condensate and high humidity - this is not a malfunction, but if it always smokes a lot, it is worth considering.

3. Oil stains on the surface of the coolant in the expansion tank or in the radiator indicate the penetration of oil where it should not be.

The reason is most likely a faulty cylinder head gasket. It's worth at least checking it out.

4. Bubbles coming out through expansion tank or radiator indicate penetration of exhaust gases into the coolant. There is a hole somewhere, and most likely it is in the head gasket. A certain amount of bubbles may appear when replacing the coolant - this is normal, but if the antifreeze constantly "bubbles" - then something is wrong.

five . Clogged oil filler neck

6. Antifreeze goes out from under the mounting studs exhaust manifold

8. Water from the radiator enters the cylinder block - it is necessary to replace the radiator