The engine does not start the first time: 12 reasons and what to do

Do you turn the ignition key, but the engine only catches on the second or third try? The situation is familiar to most car owners - especially in the cold season. However, if the problem recurs regularly, this is a sign of a problem that cannot be ignored. In 80% of cases they are to blame battery, fuel system or sensors, but there are also less obvious reasons - from worn spark plugs to errors in the ECU firmware.

In this article we will analyze all possible reasons poor engine starting the first time - from trivial to rare. You will learn how to diagnose the problem yourself, which components to check first, and when a visit to a service station is indispensable. And for car owners with GDI engines (for example, Toyota 1NZ-FE or Hyundai Gamma) and diesel engines added separate recommendations - their fuel systems are especially sensitive to the quality of gasoline and oil.

Spoiler: if the engine starts the second time only when hot, guilty with 95% probability coolant temperature sensor or air leaks in the intake manifold. And if the problem appears when it’s cold, check battery, starter and fuel pump.

1. Battery: low charge or poor contact

The most common reason for a difficult startup is dead battery. Moreover, it is not necessarily discharged to zero: even at 11.8–12.1 V (which is considered the “norm” for many drivers), the starter may not have enough strength to crank the crankshaft at the required speed. This is especially true for diesel engines and large displacement engines (for example, V6 3.0 TDI or V8 5.0 Coyote).

How to check:

• 🔋 Measure the voltage at the terminals with the ignition off - must be no less 12.6 V. When 12.3–12.5 V The battery is already 30–50% discharged.
• 🔌 Check the voltage while cranking the starter - if it falls below 10.5 V, the battery is faulty or insufficiently charged.
• 🔧 Inspect the terminals for oxidation (white coating) and the tightness of their fit. Oxides increase resistance, due to which up to 30% of the current is lost.

Solution:

• ⚡ Charge your battery low current (2–3 A) within 10–12 hours. Quick charging “for 20 minutes” will only worsen the sulfation of the plates.
• 🔄 If the battery is older than 4-5 years, replace it - even after charging it will quickly lose capacity.
• 🧴 Clean the terminals baking soda (1 tablespoon per glass of water) and grease lithol or special lubricant for contacts.

⚠️ Attention: If after an overnight stay the battery voltage drops below 12.2 V, in the car there is leakage current (for example, due to a faulty alarm or radio). Normal leakage current - no more 50–70 mA.

2. Starter: wear of bushings, bendix or brushes

If you hear when you turn the key grinding, crackling, or single clicking noises, the problem lies in the starter. Most often worn out:

• 🔗 Bendix (overrunning clutch) - does not engage with the flywheel.
• 🧲 Brushes — worn out to the limit and do not transmit current to the rotor.
• 🌀 Bushings (bearings) - due to play, the rotor touches the stator.

Diagnostics:

• Try starting the car from the pusher (for manual transmission). If the engine starts, the starter is at fault.
• Shine a flashlight on the starter while cranking - if visible sparking, the brushes require replacement.
• Check control wire voltage (thin wire on the solenoid relay) - should be 12 V when turning the key.

Symptom	Possible malfunction	Repair cost (RUB)
Single click, starter does not turn	Defective solenoid relay	1 500–3 000
Grinding noise on startup	Worn bendix teeth or flywheel	4 000–8 000
The starter turns slowly, despite a good battery	Worn brushes or bearings	3 500–6 000
The starter works, but does not crank the engine	Bendix slipping	2 000–4 500

Solution:

• 🔧 If the starter clicks but doesn't turn, try to knock on it hammer with wooden handle (sometimes it helps to “revive” the brushes).
• 🔄 On cars with automatic transmission (for example, Audi A4 B8 or Nissan Qashqai) the starter is replaced only as an assembly - repairs are not provided.
• 🛠️ On old machines (for example, VAZ 2107 or Gazelle) can be replaced separately with bendix or bushings.

3. Fuel system: pump, filter, injectors

If the engine Doesn't start the first time, but then works fine, the problem may lie in the fuel system. Especially relevant for cars with injector and diesel engines, where fuel pressure is critical for starting.

What to check:

• 🛢️ Fuel pump - if you can’t hear it when you turn on the ignition buzzing in the rear seat area (or under the hood of diesel engines), the pump does not create pressure.
• 🔄 Fuel filter - a clogged filter can only allow fuel to pass through after several starting attempts.
• 💉 Injectors - if one or more injectors "pouring" (they allow fuel to pass through when closed), the engine will flood.
• 🌀 Fuel pressure regulator — in the event of a malfunction, the pressure in the ramp drops 5–10 minutes after stopping the engine.

Diagnostics:

• Check fuel rail pressure (the norm for most injectors is 2.8–3.2 bar). On diesel engines the pressure is common rail there must be 250–300 bar at idle speed.
• If the engine "enough" and stalls, try starting it with pressed gas pedal - if it starts, the injectors or mass air flow sensor are to blame.
• On diesel engines, pay attention to glow plugs - if one does not work, a cold engine will be difficult to start.

⚠️ Attention: On vehicles with start-stop system (for example, Volkswagen Golf 6 or Ford Focus 3) frequent short trips lead to premature wear of the fuel pump. If the car has been sitting for 2-3 days and does not start, check the pressure in the system.

Listen to the pump when you turn on the ignition|

Check the pressure in the rail with a pressure gauge |

Inspect the fuel filter for contamination |

Check spark plugs/glow plugs for carbon deposits|

Reset ECU errors (if "Check Engine" is on)

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4. Sensors: Mass air flow sensor, DPKV, temperature sensor

Modern engines are equipped with dozens of sensors, and the failure of even one can lead to bad launch. The most "problematic":

• 🌡️ Coolant temperature sensor (DTOZH) — if it’s lying, the ECU incorrectly calculates the fuel-air ratio.
• 🌀 Mass air flow sensor (MAF) — if dirty or malfunctioning, the engine will “choke.”
• 📊 Crankshaft position sensor (CPS) - if the signal is weak, the ECU cannot accurately determine the injection moment.
• 🔥 Knock sensor - on some engines (for example, Renault K4M) its malfunction leads to “triple” when starting.

How to check:

• Read errors to the scanner (eg. ELM327). Codes P0115–P0119 - problems with DTOZH, P0100–P0104 — DMRV, P0335–P0339 - DPKV.
• Check sensor resistance multimeter (for example, for DTOZH on VAZ 2110 norm - 2–3 kOhm at +20°C).
• Inspect the connectors for oxidation or broken wires - especially relevant for DPKV, which is located next to the crankshaft pulley.

Solution:

• 🧴 You can try cleaning the air flow sensor special spray (for example, LIQUI MOLY Drosselklappen-Reiniger).
• 🔧 DTOZH and DPKV are usually not repaired - only replacement. Sensor cost - from 300 to 2,000 rub.
• 📈 If the problem remains after replacing the sensor, check ECU firmware — sometimes adaptation of new sensors is required.

How to deceive the ECU with a faulty mass air flow sensor?

On some vehicles (for example, VAZ 2114 or Daewoo Nexia) you can temporarily disable the mass air flow sensor and start the car - the ECU will go into emergency mode, focusing on the throttle position sensor. However, you can’t drive like this all the time: fuel consumption will increase by 20–30%.

5. Spark plugs and high-voltage wires

Worn spark plugs or broken high-voltage wires are a classic cause. poor cold starting. Moreover, the problem can manifest itself in selectivity: for example, the engine starts the second time only in the morning, and in the afternoon - with a half turn.

Signs of malfunction:

• 🔥 Triple after starting (the engine shakes).
• ⚡ Popping sounds in the exhaust system - a sign of misfire.
• 💡 Candlelight raid: black (rich mixture), white (lean mixture), red (gasoline additives).

Diagnostics:

• Unscrew the spark plugs and inspect them. Normal clearance — 0.8–1.1 mm (depending on the model).
• Check resistance of high voltage wires - must be within 3–10 kOhm (depending on length).
• In the dark, start the engine and inspect the wires - if visible sparking, they need to be replaced.

Solution:

• 🔧 Change spark plugs set, even if one is faulty. Recommended interval - 30–50 thousand km (for iridium - up to 100 thousand km).
• 🔌 It is better to buy high-voltage wires silicone - they last longer and have less damage.
• ⚠️ On cars with ignition coils on each spark plug (for example, Ford Focus 2 or Kia Rio 3) check their resistance - normal 5–15 kOhm.

6. Engine compression and mechanical problems

If the engine Doesn't start the first time and smokes blue smoke, the problem may be low compression or wear of the cylinder-piston group. This is true for used cars 200+ thousand km or after overheating.

Reasons for low compression:

• 🔥 Piston ring wear — oil enters the combustion chamber and “floods” the spark plugs.
• 🌀 Burnt valve - compression in one cylinder will be close to zero.
• 🛢️ Coked rings - a common occurrence when driving short distances or using low-quality oil.

How to check compression:

1. Warm up the engine to operating temperature.
2. Unscrew all spark plugs.
3. Insert the compression gauge into the spark plug hole and crank the starter for 5–7 seconds.
4. Record the readings for each cylinder. Normal compression — 12–14 bar (depending on the model). The spread between cylinders should not exceed 1 bar.

Solution:

• 🔧 If compression is low in all cylinders, try decarbonization (for example, LAVR ML202).
• 🛠️ If the compression in one cylinder is close to zero, most likely the valve has burned out and the cylinder head will need to be repaired.
• 🌀 Diesels have low compression (20–24 bar) often leads to the fact that the engine does not start without “lighting up”.

7. Electronics: ECU, immobilizer, alarm

Modern cars are literally “stuffed” with electronics, and malfunctions in its operation can lead to problems starting. The most common reasons:

• 🔐 Immobilizer — the key does not recognize or the reader fails.
• 📱 Alarm — blocks startup due to a failure in the data exchange protocol with the ECU.
• 🖥️ ECU (electronic control unit) — errors in the firmware or “glitches” of the microcircuits.
• 🔌 Wiring — oxidized contacts in the ECU connectors or breaks in the “mass” wires.

How to diagnose:

• If on the dashboard immobilizer icon flashing (car with a key), the problem is there.
• Try starting the car second key — if it starts, the chip in the first one is faulty.
• Turn off the alarm (if there is a separate button) and try to start the engine.
• Check fuses (especially those responsible for the ECU and immobilizer).

Solution:

• 🔧 If the immobilizer is to blame, you can disable it programmatically (ECU firmware required).
• 📱 For alarm try reset settings or reflash the block (for example, StarLine or Pandora).
• 🖥️ If the ECU is “buggy”, sometimes it helps reset adaptations (for example, via VCDS for Volkswagen or Chiptuner Pro for domestic cars).

⚠️ Attention: On some vehicles (for example, Renault Megane 2 or Peugeot 308) after disconnecting the battery, the ECU may block the engine from starting. In this case, you will need to “train” the keys through a diagnostic scanner.

8. External factors: weather, fuel, driver errors

Sometimes the engine does not start the first time not due to breakdowns, but due to external reasons. Let's look at the most common ones:

1. Cold weather:

• 🌡️ At temperatures below -20°C The engine oil thickens, and the battery loses up to 50% of its capacity.
• 🛢️ Paraffin may form in diesel fuel, clogging the filter.
• 🔥 On carburetor engines (for example, VAZ 2106) need by suction enrich the mixture before starting.

2. Bad fuel:

• ⛽ Gasoline with low octane number or impurities leads to detonation and poor ignition.
• 🛢️ In a diesel engine, the water in the fuel will freeze in winter and block the fuel lines.
• 🔥 If after refueling the engine becomes difficult to start, drain the fuel and flush the tank.

3. Driver errors:

• 🔑 Incomplete key turn — if the ignition is turned on, but the starter does not crank, the battery is discharged.
• 🚗 Forgotten switched on load (headlights, stove) - can drain the battery overnight.
• 🛠️ Late oil change - Thick oil makes cranking difficult.

Solution:

• 🌡️ Use in winter preheater (for example, Webasto or Eberspächer).
• ⛽ Refuel at proven gas stations. Mandatory for diesel engines in winter antigel additive.
• 🔧 Check before the cold season electrolyte density in the battery (normal - 1.27 g/cm³).

FAQ: Frequently asked questions about poor engine starting

❓ The engine starts the second time only when hot. What is the reason?

In 90% of cases it is to blame coolant temperature sensor (DTOZH). He lies to the ECU that the engine is cold, and it fills the cylinders with fuel. Also check:

• 🔥 Injectors — they can “pour” after stopping the engine.
• 🌀 Fuel pressure regulator — if it doesn’t hold pressure, gasoline flows into the tank.
• 🛢️ Air leak in the intake manifold (for example, through a cracked pipe).

Diagnostics: after stopping the engine, unscrew the spark plugs - if they are wet, the problem is an over-rich mixture.

❓ Why doesn’t a diesel engine start the first time, but a gasoline one does?

Diesel engines are more sensitive to:

• 🛢️ Fuel quality — paraffin in diesel fuel clogs the filter in winter.
• 🔥 Condition of glow plugs — if one does not work, a cold engine will not start.
• 🌀 Fuel system pressure - required to start 250–300 bar.
• 🔋 Battery condition — a diesel engine needs a more powerful starter.

Solution: use in winter antigel and warm up the glow plugs 2–3 times before launch.

❓ Could a bad start be related to the timing belt?

Yes, if:

• 🔗 Timing belt/chain jumped — the valve timing is off.
• 🌀 Rollers or tensioner worn out — the belt slips when starting.
• 🛠️ Burnt out cylinder head gasket — compression drops, and antifreeze enters the cylinders.

Signs: the engine may “shoot” at the exhaust pipe or intake manifold, and may also stall after starting.

❓ How does ECU firmware affect engine starting?

Incorrect firmware can:

• 📈 Inflate/lower fuel-air ratio (the engine floods or “dries out”).
• 🔧 Change ignition timing - the spark does not form at the optimal moment.
• 🛠️ Disable sensors (for example, a lambda probe), which causes the ECU to work “blindly”.

Solution: if the problem appeared after chip tuning, return stock firmware.

❓ Why doesn’t the engine start after a long period of inactivity (several months)?

Reasons:

• 🛢️ The gasoline has evaporated from the fuel system (especially important for carburetors).
• 🔋 The battery is completely discharged or sulfated.
• 🌀 Oil drains from critical components (for example, from a turbine on diesel engines).
• 🐭 Damaged wiring rodents or contacts have oxidized.

Solution: Before starting:

1. Charge or replace the battery.
2. Crank the engine with the starter no spark (disconnect the coils) to coat the cylinder walls with oil.
3. If it is a carburetor, pump gasoline into the float chamber.