A sharp metal click when turning the key in the ignition lock often indicates that traction-relay The starter worked, but the electric current did not enter the winding of the electric motor. At this point, the driver must immediately stop the start attempts and check the status of the battery terminals, as it is oxidized contacts or discharged. battery This is the reason for the lack of scrolling. If you ignore this symptom and continue to spin the starter, you can completely plant the battery or provoke a fire of wiring due to overheating of places of poor contact.
A deaf, protracted hum or low-frequency hum without subsequent engine grip indicates that starter Correctly rotates the crankshaft, but the cylinders do not receive fuel or there is no spark on the candles. In such situations, the characteristic sound of work starter It changes, becoming lighter and faster, as compression in the cylinders is not created due to the lack of ignition of the mixture. Experienced auto mechanics recommend at this point to listen to the work gas pump when the ignition is turned on to eliminate problems with the supply of fuel.
Dry, frequent crackling, resembling the work of a sewing machine, is a sure sign that bondix The starter cannot catch the engine flywheel. This sound is caused by the fact that the gear drive is either worn, jammed, or the flywheel itself has damaged teeth in the engagement area. Continuous work in this mode is guaranteed to lead to destruction. flywheel It would require expensive repairs to dismantle the gearbox.
Analysis of Starter Clicks and Electrical Chain
When a single loud click is heard when you try to start the engine, and then there is silence, this is a classic symptom of a malfunction in the power chain. starter. The problem most often lies in the traction-relayThe contacts inside of which could burn with time or poor quality of the metal. In this case, the relay winding receives power and draws in the core, issuing the same click, but the pentacles do not close, and the current does not go to the rotor.
If there are many clicks, and they follow with a high frequency, creating the effect of rattling, then there is a critical discharge. battery. The current power is enough only to pull the core of the relay, but to hold it in working position or scrolling the engine, energy is no longer enough. The relay releases, the circuit breaks, the voltage at the terminals is slightly restored, and the cycle repeats again and again, producing a characteristic sound.
⚠️ Warning: Do not try to light up a car with a dead battery if you hear a frequent crack of the relay, without first checking the engine weight. Poor contact with the “mass” can cause a power surge and damage the electronics of the donor or recipient.
For accurate diagnosis, it is necessary to check the voltage at the terminals battery under load. If the voltmeter shows a drop below 9-10 volts when trying to start, the current source requires charging or replacing. It is also worth examining the thick wire going from the plus terminal to the starter: The oxidation of the tip often creates a resistance that blocks the start.
Extraneous noises during the rotation of the crankshaft
If the starter cheerfully turns the engine, but the start does not occur, you should pay attention to the nature of rotation. The normal sound of scrolling a working motor is a rhythmic, uniform "jj-j-j-j-j-j." If you hear extraneous knocking, grinding or uneven slowing of rotation, this indicates mechanical problems inside. combustion engine.
One of the most dangerous sounds is the metal knock that occurs at the bottom of the cylinder block. It could indicate a turnaround. root-liners Crashwall. In this state, further scrolling by the starter can lead to bullying of the crankshaft necks and the need for major repairs or replacement of the unit. If you hear a similar sound, further launch attempts are strictly prohibited.
Whistling sound when scrolling often indicates problems with the gas distribution mechanism (see below).GRMA). If the belt or chain jumped on several teeth, the valves can open out of time, creating a characteristic noise and reducing compression. In the worst case, when the belt breaks on some engines, the pistons hit the valves, which is accompanied by a loud crack and jamming of the engine.
- 🔊 A uniform hum without grasping is the absence of spark or fuel.
- 🔊 Metal slanting in the depths of the motor - problems with the crank-shaking mechanism.
- 🔊 Whistling and uneven rotation - malfunction GRMA or compressions.
- 🔊 Cotton in the intake manifold - the back blow of the mixture due to knocked phases.
When diagnosing engine sounds, ask the assistant to turn the starter, and at this moment, put your hand to the body or use a stethoscope (or long screwdriver), putting your ear to the handle to better hear the vibrations of the block.
The sounds of a faulty bendix and flywheel
A piercing screech or grind immediately after clicking the traction relay, but before the engine starts rotating, almost always indicates wear of the gear. bendix or flywheel teeth. The starter drive mechanism tries to catch on to the flywheel, but because of the slicked teeth, a slip occurs, accompanied by an unpleasant metal sound.
Sometimes the sound is like the crunch of a glass-beater. This happens when the teeth are bendix They fall exactly on the teeth of the flywheel, they can not get into the hook and begin to rub against the ends. The starter at this point may buzz, but the kneel does not turn. If you slightly turn the crankshaft manually (for a pulley) and try again, the sound may disappear, which will confirm the local wear of the flywheel crown.
It is important to note that on cars with manual transmission sometimes there is a situation where the starter spins idly with a characteristic buzzing sound, although the bendix is serviceable. This could mean that the starter shaft slats have worn out and the torque is not transferred to the gear. Visually, the gear is extended, but rotation does not occur.
How to check the condition of the flywheel without removing the starter?
Remove the starter and examine the flywheel teeth through the opening opening, turning the crankshaft. If several teeth are visible chipped or cut edges, the crown requires replacement. Temporarily you can try to catch on the undamaged area, turning the engine.
Hydraulic shock and the sounds of liquid hitting cylinders
One of the most terrifying sounds that a car owner can encounter is a sharp blow or a series of blows when scrolling with a starter, after which the rotation stops abruptly. This is a sign of a hydraulic shock when water or a large amount of fuel is hit in the cylinders that is not compressed, unlike a gas-air mixture.
If the car stalled in a deep puddle, and after that the engine emits a thud when trying to start and no longer spins, then the water got through the air-intake into the cylinders. The piston hit a water plug at the top dead point. Further attempts to start will lead to a failure of the rod or deformation of the cylinder head.
A similar sound can be observed when a malfunction occurs. fuel-nozzleIf it pours fuel into a closed cylinder. Liquid gasoline or diesel fills the volume of the combustion chamber, and during the compression stroke there is resistance. To distinguish this sound from mechanical jamming can be by turning spark plugs: if after their removal the starter twisted easily, the reason was the re-enrichment of the mixture.
⚠️ Warning: Never force the engine to turn a starter if there is a suspicion of a hydraulic shock. This is guaranteed to lead to expensive repairs of the cylinder block and the shaky piston group.
Diagnostics by sound of the fuel pump
Before turning the starter, when the ignition is turned on in the cabin, a quiet hum or buzzing lasting 2-3 seconds should be heard. It's electric. fuel-pumpThis creates the necessary pressure in the fuel ramp. The absence of this sound is the first warning sign that the car may not start due to lack of fuel.
If instead of a smooth buzzing, a discontinuous, howling or creaking sound is heard, this indicates that the resource is intermittent. fuel pump It's coming to an end. The pump motor works with overload, possibly due to contamination of the filter mesh or wear of the brushes. At any moment, such a pump can finally fail, leaving the car on the side of the road.
Sometimes the sound of the pump may not be heard at all due to noise insulation or proper operation of the system, which is turned on only when scrolling with the starter (on some modern models). However, if the sound remains unnaturally loud or vibrating when the fuel cover is open or the pump hatch is removed, a replacement of the assembly is required.
☑️ Primary audio diagnostics before calling the tow truck
Table of audible diagnostics of malfunctions
To systematize the knowledge gained and quickly orientate the situation, use the table below. It will help to compare the heard sound with the most likely cause of the malfunction.
| Type of sound | Probable cause | Action required | Risk of further exploitation |
|---|---|---|---|
| Single click | Failure of traction relay or discharge of the battery | Check the terminals, charge the battery | Full battery discharge |
| Frequent crackling (fragment) | Critical battery discharge | "Lighten" or charge the battery | Damage to electronics |
| Dry grinding | Wear of a bendix or flywheel crown | Replacement of starter or flywheel | Flywheel destruction |
| No spinning hum | A jammed engine or starter | Check the free rotation of the pulley | Starter burnout |
| Smooth humming (without grasping) | No spark or fuel. | Diagnostics of ignition and delivery systems | The bay of candles with fuel |
Specific sounds of diesel and injection engines
Diesel engines at start make louder and harder scrolling sound due to the high degree of compression. However, if the sound becomes similar to metal hitting metal ("dieselite"), it may indicate an early ignition or malfunction. TNVD (high pressure fuel pump) The characteristic clinking sound of nozzles when the engine is running is the norm, but when starting it should not be.
In injector gasoline engines, a frequent cause of start failure when brisk scrolling is a malfunction. crankshaft-sensor. The sound of the starter in this case is absolutely normal, the engine rotates easily, but does not “grab”. It is impossible to distinguish this malfunction by sound, computer diagnostics is required.
It is also worth mentioning the sound of "dieseling" when the engine continues to run or twitch after the ignition is turned off. This phenomenon is caused by the self-ignition of the mixture from overheating or scorching in the combustion chamber. Although the machine is technically “started” at this point, this mode of operation is harmful to the car. piston-group And it requires cleaning the engine of the stain.
The main conclusion: Start-up sound is the primary diagnostic tool. The ability to distinguish between the click of the relay, the crack of the bendix and the starter hum allows you to weed out 80% of false tow truck calls and save time on finding a fault.
Frequently Asked Questions (FAQ)
Why does the starter click but not spin, even though the battery is new?
If the battery is guaranteed to be serviceable and charged, the reason lies in poor contact. Check the terminals for oxidation, as well as the "mass" (contact of the engine with the body). It is also possible to break inside the starter itself or a malfunction of the retracting relay, which does not supply current to the windings.
Is it dangerous for a starter if the car does not start for a long time and he is constantly spinning?
Yes, it's extremely dangerous. The starter is not designed for long-term continuous operation. With a long scrolling, it overheats, the insulation of the windings can melt, which will lead to a short circuit. The battery also goes down quickly. To spin the starter you need jerks for 5-10 seconds with pauses.
The car does not start and only a silent click is heard, what to do?
A quiet click often indicates that current does not reach the retracting relay due to a weak battery charge or poor contact in the circuit. Try cleaning the terminals, moving the wires going to the starter, or letting the battery "rest" for 10-15 minutes before a new attempt.
Could the sound of a non-starting machine indicate a problem with the GRM?
Indirectly, yes. If the spinning sound is too light, “empty” and not rhythmic when scrolling with a starter, this may mean no compression. One of the reasons for loss of compression is a jump of the timing belt or a break, because of which the valves do not close in time.
What does the whistle mean when the engine starts?
The whistle usually emits a slipping belt of the generator or hinged units. When starting, the starter consumes a lot of energy, the generator gives a load on the pulley, and if the belt is stretched weakly or worn, a whistle is heard. Less often, the bearings of the starter itself can whistle when rotating.