The car won't start - what should I do? Full analysis of reasons and solutions

Have you turned the key in the ignition, but instead of the usual growl of the engine, there is silence or faint clicks? The situation when the car won't start, is familiar to every car owner. The reasons can be either trivial (dead battery) or serious (damage to the fuel pump or control unit). In this article we will look at all possible scenarioswhy the engine refuses to start, and we will give clear instructions on what to do in each case.

It is important to understand: the troubleshooting algorithm depends on symptoms. The car may not respond to the key at all, spin the starter “idle”, start and immediately stall - or make strange sounds. We have structured the material so that you can quickly navigate the car's behavior and find a solution. And if you are not confident in your abilities, at the end of the article there is FAQ with answers to frequently asked questions.

1. The car does not respond to the key: check the battery and electrics

If when you turn the key there is no reaction - no sound, no clicks, no dashboard lights - the problem is almost certainly power supply. In 80% of cases, a discharged or faulty battery is to blame. But there are other pitfalls.

First thing to do:

• 🔋 Check it out battery voltage multimeter (norm: 12.6–14.4 V). If below 11.8 V, the battery is discharged.
• 🔌 Take a look terminals for oxidation or poor contact. Often it is enough to clean them with sandpaper.
• 🔧 Make sure that ground wire (negative terminal → body) is not torn off or corroded.
• 🚗 Try turning on the headlights or radio. If they don't work, the problem is definitely in the diet.

If the battery is ok, but the car is still “dead”, check:

• 🔑 Ignition switch — the contact group may have burned out (characteristic sign: the device does not light up).
• 🛡️ Fuses (especially those responsible for the starter and ignition system). On Lada Vesta, for example, this F31 (10A).
• 🔄 Starter relay - sometimes it is enough to knock it (for example, on Toyota Corolla this helps).

⚠️ Attention: Never “light” a car with a faulty battery from a running donor engine! This can damage the generator or electronics of both cars. First plug the donor, then connect the wires.

2. The starter turns, but the engine does not start: fuel vs ignition

If the starter vigorously rotates the engine, but the motor “does not catch on,” the reasons are divided into two groups:

1. Problems with the fuel system (gasoline does not enter the cylinders).
2. Ignition faults (no spark or phases are out of order).

How to diagnose:

Symptom	Probable Cause	How to check
The starter turns, but the engine does not “get enough”	Doesn't work fuel pump	When you turn on the ignition, you should hear a buzzing sound from the pump (5–7 seconds). If there is silence, check the fuse Fuel Pump.
The engine "sneezes" but does not start	Crowded injectors or fuel filter	Check the rail pressure (normal: 3–4 bar). On Volkswagen Passat B6 There is a special fitting for this.
The candles are filled with gasoline	Faulty spark plugs or coils	Unscrew the spark plugs: if they are wet, dry them or replace them. Check the coils with a tester (resistance should be 0.5–2 ohms).
The engine starts and immediately stalls	Doesn't work crankshaft sensor (DPKV)	Check with an oscilloscope or replace with a known good one. On Renault Logan this is a common problem.

If you suspect a fuel problem, do the following:

Remove the fuel pump fuse and check its integrity|

Listen to the sound of the pump when you turn on the ignition (should hum for 5-7 seconds) |

Crank the starter with the spark plug unscrewed - if gasoline splashes, the pump is working |

Measure the pressure in the fuel rail (standard: 3–4 bar)|

Inspect the fuel filter for clogging -->

Critical information: On diesel engines (for example, BMW 320d or Mercedes OM642) the reason may be airing of the fuel system. In this case, the injection pump will need to be pumped - this is difficult to do without special equipment.

3. The starter clicks, but does not turn: problems with the starter or battery

Single or multiple clicks When you try to start the car they say that the starter cannot crank the engine. This is a typical symptom:

• 🔋 Dead battery (there is voltage, but not enough to start).
• 🔩 Burnt contacts on the starter or solenoid relay.
• 🛠️ Brush wear or starter anchors (typical for cars with mileage >150 thousand km).
• 🔄 Jammed Bendix (gear does not mesh with flywheel).

How to proceed:

1. Try it push start the car (only for manual transmission!). If the engine starts, the problem is in the starter or battery.
2. Tap the starter housing gentle blows of the hammer (sometimes helps with burnt contacts).
3. Check solenoid relay: When you turn the key, a clear “clack” sound should be heard. If it is not there, the relay is faulty.
4. Measure starter current with pincers: the norm is 150–200 A. If there is current but no rotation, the starter is “dead”.

⚠️ Attention: Do not try to “torment” the starter for a long time if it does not turn! Each start discharges the battery, and prolonged attempts can burn the winding. Maximum 3-4 attempts with an interval of 1 minute.

Mechanical (manual transmission)|

Automatic (automatic transmission)|

Robotic (AMT/DCT)|

CVT (CVT)|

4. The engine starts and immediately stalls: sensors and ECU

If the engine “cages”, but stalls after 1–3 seconds, the problem lies in:

• 📡 Crankshaft sensor (DPKV) - without its signal, the ECU does not know when to give a spark.
• 🔥 Mass air flow sensor (MAF) — incorrect readings lead to a lean mixture.
• 🛢️ Idle air control (IAC) - if it is jammed, the engine stalls without pressing the gas.
• 🖥️ Electronic control unit (ECU) — firmware failures or damage to the board are possible.

Diagnostics:

1. Connect OBD-2 scanner (for example, ELM327) and check the error codes. Frequent codes:
   • P0335 - DPKV malfunction;
   • P0100 — problem with the mass air flow sensor;
   • P0505 - IAC error.

Check wiring for breaks or oxidation (especially at sensor connectors).

If there are no errors, but the engine stalls, try reset ECU adaptations (disconnect the battery for 10 minutes).

On vehicles with gas equipment (LPG) the reason may lie in incorrect calibration of the gas ECU or gas leak. Check:

• 🔧 Tightness gas pipelines (wheezing or smell of gas).
• 📉 Pressure in gas reducer (norm: 1–1.2 bar).
• 🔄 Switching from gasoline to gas (should occur automatically when warming up to 40–50°C).

How to trick the ECU to start in emergency mode?

On some vehicles (for example, Opel Astra H or Chevrolet Lacetti) you can temporarily disable the crankshaft sensor so that the ECU goes into emergency mode. To do this:

1. Remove the chip from the DPKV.
2. Turn the ignition key to the ON position (do not start!).
3. Wait 10 seconds and plug the chip back in.
4. Start the engine - it will work with an error, but will allow you to get to the service station.

Attention: This method does not work on all cars and may damage the catalytic converter!

5. The car does not start “hot”: reasons and solutions

If the car starts normally “when cold”, but refuses to start after warming up, the following are to blame:

• 🔥 Ignition coils - when heated, the insulation cracks and a spark “breaks” onto the body.
• 🛢️ Fuel pump - overheats and turns off (typical for Nissan Almera and Kia Rio).
• 🔧 Coolant temperature sensor (DTOZH) — the ECU gives incorrect readings.
• 💨 Canister valve — jams when heated and over-enriches the mixture.

How to check:

1. After stopping the engine, wait 10-15 minutes and try starting it again. If it starts, the problem is fuel pump overheating.
2. Check spark on the spark plugs after warming up: if it’s not there, the coils or wires are to blame.
3. Replace DTOZH to a known good one (inexpensive, but often at fault).

On diesel engines (for example, Peugeot 308 1.6 HDi) the problem may be injection pump plunger pair, which loses its tightness when heated. The solution is to replace or repair the pump.

6. The engine “starts”, but does not start: compression and timing

If the starter turns, fuel flows, there is a spark, but the engine “does not catch” or runs intermittently, check:

• 🔧 Compression in cylinders (norm: 12–14 bar, spread between cylinders no more than 1 bar).
• 🔄 Timing belt or chain - if it jumps 1-2 teeth, the valve timing is off.
• 💥 Valve burnout or cylinder head gaskets (characteristic sign: white smoke from the exhaust).
• 🛢️ Cylinder oil - if the compression is low, but after pouring 5-10 ml of oil into the cylinder it increases, the culprit is rings.

How to measure compression without a compression gauge:

1. Unscrew all spark plugs.
2. Insert into spark plug hole thick rag (so that the piston creates resistance).
3. Crank the starter - you can roughly estimate the compression by the force (if the rag comes out easily, the compression is low).

If you suspect problems with the timing belt:

• Remove belt/chain cover and check that the marks match.
• On 16 valve engines (for example, VAZ-2112) if the valve belt breaks, the valve bends - the cylinder head will need to be repaired.
• On 8-valve (for example, VAZ-2109) valves are usually not affected.

⚠️ Attention: If the engine “starts” but does not start due to low compression, do not try to turn it for a long time! This may lead to rotation of the liners (especially on worn engines).

7. The car does not start after washing or rain: moisture and electronics

If the car stops starting after washing or heavy rain, the problem lies in moisture ingress to:

• 🔌 High voltage wires or ignition coils;
• 🖥️ Electronic control unit (ECU);
• 🔋 Sensor connectors (DPKV, mass air flow sensor, lambda probe);
• 🔧 Starter or generator.

What to do:

1. Dry the engine compartment heat gun or a hairdryer (do not direct hot air at the plastic!).
2. Check fuses - Moisture can cause a short circuit.
3. Process contacts WD-40 or electrical spray (for example, Liqui Moly Electronic-Spray).
4. If the car does not start after washing the engine, remove the distributor cap (if equipped) and dry it.

On vehicles with hybrid electronics (for example, Toyota Prius) moisture can cause malfunctions inverter. In this case, only diagnostics at a service station will help.

FAQ: Frequently asked questions about engine starting problems

❓ Why doesn’t the car start after refueling?

Probable reasons:

• 🛢️ Bad fuel (diluted or with impurities). Solution: drain the gasoline, rinse the tank, replace the fuel filter.
• 🔧 The strainer is clogged in the gas pump (typical after refueling at dubious gas stations).
• 💥 Detonation due to low octane number (for example, they filled in 92 instead of 95).

If after refueling the car starts, but runs intermittently, drain the fuel and fill it with quality fuel!

❓ Is it possible to start a car from a pusher on an automatic machine?

No! Starting from a pushrod is only possible with mechanical box. On an automatic transmission (automatic transmission, CVT, robot) this will lead to:

• 🔧 Breakdown torque converter;
• 💥 Out of order planetary mechanism;
• 🛑 Loss of warranty (if the car is being serviced).

The exception is some old machines (for example, Automatic transmission on Mercedes W124), but it's not worth the risk.

❓ Why does the starter turn, but not “enough”?

Reasons:

1. No fuel (pump does not work, filters are clogged).
2. No spark (coils, spark plugs, ignition module are faulty).
3. No compression (burnout of the valve, stuck rings).
4. Timing phases are knocked out (belt/chain jumped).

Start by checking fuel pump and sparks on candles.

❓ What to do if the car doesn’t start in the cold?

Algorithm of actions:

1. Check battery charge (in cold weather the capacity drops by 30–40%).
2. If the battery is weak - recharge or “light up” from another car.
3. Check candles — in cold weather they are often filled with gasoline. Solution: unscrew, dry, crank the engine without spark plugs for 10 seconds, then screw back in.
4. Use antigel additives for diesel (for example, Liqui Moly Diesel Fliess-Fit).
5. If the car is on gas, start only on gasoline!

On diesel cars (for example, Volkswagen Touareg 3.0 TDI) in cold weather maybe frozen fuel filter. The solution is to warm it up with a hair dryer or fill it with warm diesel fuel.

❓ How long can you turn the starter without consequences?

Recommendations:

• 🔋 Gasoline engine: no more than 10–15 seconds per attempt, then a pause of 1 minute.
• 💨 Diesel engine: no more than 7–10 seconds (glow plugs overheat).
• ⚠️ Maximum 3–4 attempts in a row, then a mandatory break of 5–10 minutes (so as not to burn the starter).

If the engine does not start after 3-4 attempts, look for the reason, and do not continue to turn it!