During operation, the engine operates in different modes. One of these is idling. This is the engine in neutral gear with the clutch disengaged. At this point, the flywheel is disconnected from the transmission. No torque is transmitted, that is, the motor is idling (hence the name). If engine vibrations occur at idle, this is a serious reason for diagnosis. After all, a serviceable motor should not transmit vibration to the body. In today's article, we will consider why this problem arises and how it can be eliminated.
What is the speed?
If you reset the box to “neutral”, the tachometer needle drops to 800-1000 rpm. This parameter may differ slightly on different engines, but it does not go beyond this. If the speed is lower, the motor will simply stall.
But increased "idle" are harmful to the motor. So not only a lot of fuel is consumed, but engine elements also wear out more. Next, we consider the reasons why there is increased engine vibration at idle.
Motor friction
This is a generic name if one (and possibly several) cylinders does not work in the engine. Most passenger cars use inline 4-cylinder engines. Therefore, if one of them does not work, this problem is called “triple”. As you press the accelerator, the speed will increase, and the vibration will partially disappear. But this is not a solution to the problem, as the motor power is reduced by 20-40 percent. Also increases fuel consumption (about the same). Vibration of the engine at idle will be transmitted not only to the body, but also to the steering wheel. This is especially noticeable when driving with a load (for example, with a trailer).
It is worth noting that the problem is dangerous not only with uncomfortable driving and high fuel consumption. With such a motor, the elements of the crankshaft wear out. Fuel enters one of the cylinders, which does not burn, but only leaches the grease. As a result, strong badasses form, rings wear out. If you use such a motor for a long time, you can get the ellipse of the cylinders.
How to solve a problem? Candles
First of all, we look at their condition. Elements are twisted with a specialized key and are tested.
To do this, use a small device in the form of a gun. How to use it? The cap should be put on the top of the candle (where the high-voltage wire is connected), and the metal tip at the outlet of the gun should be attached to the side where the thread is. Next, pull the trigger and look at the candle. If she gives a spark, then everything is fine with her. If not, then it is she who causes the engine to vibrate at idle. The candle does not produce a spark, which is why the mixture is wasted, not combustible. When diagnosing, it is worth examining all the candles. The problem can be found in any of the cylinders (it is impossible to visually determine the “tripping” cylinder).
Trambler, coil, wires
The next problem is improper ignition. So, even with a working candle there may be gaps. This is due to a worn ignition coil or high-voltage wires themselves. The latter is very simple to check - in the dark, open the hood and on a working engine, inspect their condition. If sparks come out of the wires, then they are “broken” and must be replaced. As for the coil, it is possible to determine its malfunction only when the installation is known to be working. It is worth noting that the number of coils may differ depending on the design features of the engine (from 1 to 4 or more).
Another cause may be an incorrect ignition timing. This happens on machines equipped with a distributor. You can adjust the parameter by twisting its body relative to the camshaft. You can set the SPD by eye. After adjustment, the car is accelerated to 60 kilometers per hour and includes 4th gear. The machine must not detonate. If so, then the angle should be adjusted in the opposite direction.
Also, tripling occurs due to improper position of the timing belt or timing chain. The latter has the ability to stretch. As a result, the phases shift even when the chain does not even jump to the tooth. Check that the marks match and replace the drive if necessary. Chain changes every 100-150 thousand, belt - 60.
Vibration idle diesel engine
As you know, on such engines the mixture ignites on its own, from the compression force. There are no coils and spark plugs. But what if there are vibrations of the engine of the car idling? The reason lies in the fuel supply. Nozzles and high pressure fuel pumps are responsible for this process. The latter has a special adjustment screw. They set the amount of diesel fuel to maintain the given speed.
Also, engine vibration at idle occurs due to clogged nozzles. They may not spray fuel correctly or supply it in limited portions. You can check them through the K-Line adapter (computer diagnostics).
The program will show the pressure in the nozzles in real time. The parameter should not go into minus and differ greatly from neighboring nozzles. Optimal data is zero or one.
KShM elements
This is perhaps the most serious problem that can cause vibration.
So, this problem occurs due to a cracked crankshaft or a worn flywheel. This happens if the engine is subjected to regular loads. Sometimes the cost of repairing the crank mechanism is comparable to the price of a contract motor.
Pillows
Engine idle vibration may occur due to improperly mounted power unit. As a result, there is a strong imbalance. The engine is mounted to a frame or body (if one is a carrier) by means of rubber mounts. Over time, they become loose, dry out and deformed. The problem is dangerous not only with engine vibrations at idle, but also with skewed boxes. If it's an “automaton,” he can kick. And on the "mechanics" can hardly switch gears.
Typically, a car uses three pillows. Two go to the engine and one to the checkpoint. Vibration of the engine at idle can occur even after the failure of one of them. The element begins to loosen up to 250 thousand kilometers. Compared to a deformed flywheel or crankshaft, this problem is not so bad. The cost of a new pillow is not more than a thousand rubles, and you can replace it yourself.
Conclusion
So, we found out, because of which there is increased vibration at idle in the car engine. As you can see, the reasons can be very different - from small ones with candles and a pillow to serious ones related to the crankshaft and flywheel. In any case, the problem must be urgently addressed. Otherwise, other engine components will undergo serious wear.