Why does the engine take a long time to start: causes and solutions

Have you turned the key in the ignition, but the engine is stubbornly “silent” or only catches on after several attempts? The problem of taking a long time to start the engine is familiar to many car owners, especially in the cold season. But if in the summer the starter turns sluggishly, and in the winter the car refuses to start at all the first time, this is a clear signal: something is wrong with the car.

In this article we will look at all possible reasonswhy the engine takes a long time to start - from a banal discharged battery to serious malfunctions of the fuel system or electronics. You will learn how diagnose the problem yourself, what symptoms indicate a specific breakdown, and what to do to return the car to its former “throttle response”. And also - when you can handle it on your own, and when it’s better to go straight to the service station.

Spoiler: in 80% of cases, only 3 components are to blame. But first things first.

1. A weak battery is the first reason for a long startup

If the engine hard to start when cold, but after several attempts it “catch”, the culprit is often the battery. Even if the battery is not completely discharged, its capacity may not be enough to crank the starter at the required speed - especially in cold weather.

How to check? Turn on the headlights or stereo: if the lights are dim and the sound is intermittent, the battery is low. Another test - terminal voltage with the engine off (should be 12.6–12.7 V). If less 12.4 V — The battery requires charging, below 11.9 V - deep discharge.

• 🔋 Low battery — they forgot to turn off the lights and listened to music for a long time in the parking lot.
• ❄️ Winter factor — in cold weather, the battery capacity drops by 30–50%.
• 🔌 Oxidized terminals — a white coating disrupts contact.
• 🕒 Old battery — after 4–5 years of operation, it loses capacity.

⚠️ Attention: If after charging the battery the battery quickly discharges again, the problem may be generator (does not charge) or leakage current (for example, due to a faulty alarm).

Solution:

• Charge the battery with a charger (current - 10% of the battery capacity).
• Clean the terminals with sandpaper or a special cleaner (for example, LIQUI MOLY Batterie-Pol-Fett).
• Check the idle voltage (should be 13.8–14.4 V). If less, the generator is faulty.

2. Problems with the starter: why does it turn slowly or with a delay?

The starter is an electric motor that spins the crankshaft to the required speed. If he turns tight, you hear extraneous sounds (grinding, clicking) or a delay before starting, the problem may be there.

Common faults:

• 🔧 Brush wear — over time they wear out, and contact with the collector deteriorates.
• 🧲 Burnt contacts of the solenoid relay — the starter does not “catch” the first time.
• ⚙️ Bendix wear — the gear does not mesh with the flywheel.
• 🔋 Poor contact on the power cable - check the ground and positive cable.

How to diagnose? Try to push start the car (for manual transmission). If the engine starts, the problem is definitely in the starter or battery. Another test: when you turn the ignition key, you should hear a clear solenoid relay click. If it is not there, the relay is faulty.

Symptom	Probable Cause	Solution
The starter doesn't turn, it just clicks.	The battery is discharged or the solenoid relay is faulty	Charge the battery or replace the relay
The starter turns slowly, the engine does not catch	Worn brushes or bearings, weak battery	Check the battery, inspect the starter
Grinding noise on startup	Worn bendix teeth or flywheel	Replace bendix or starter assembly
The starter works after the engine starts	Solenoid relay contacts sticking	Replace relay or starter

⚠️ Attention: If the starter “consumes” too much current (for example, when starting all the devices go out), this may indicate turn-to-turn short circuit in the windings. In this case, repair is useless - only replacement.

3. Problems with the fuel system: from filters to injectors

If the battery and starter are ok, but the engine takes a long time to catch on or stalls immediately after starting, the fuel system is at fault. Here are the key weaknesses:

• ⛽ Clogged fuel filter — limits the supply of gasoline/diesel.
• 🔥 Faulty spark plugs (for gasoline internal combustion engines) - weak spark or carbon deposits.
• 💦 Water in fuel - especially relevant for diesel engines in winter (waxing).
• 🔧 Fuel pump wear - does not create the required pressure.
• 🛢️ Clogged injectors — fuel is poorly atomized, the mixture becomes lean.

How to check? First, listen to the operation of the fuel pump when you turn on the ignition - you should hear a short buzzing sound (2-3 seconds). If it is not there, the pump does not pump. For gasoline cars, you can unscrew the spark plugs: if they wet, this is an overflow of fuel; if dry — fuel is not supplied.

Critical for diesel engines quality of diesel fuel in winter: at −10°C and below, paraffins in the fuel thicken and clog the filter. If the car does not start after refueling, most likely they sold you “summer” diesel fuel.

Unscrew the spark plugs (for gasoline internal combustion engines)|Listen to the operation of the fuel pump when the ignition is turned on|Check the pressure in the fuel rail (with a pressure gauge)|Inspect the fuel filter for contamination|Check for errors with a scanner (for example, P0171 - lean mixture)-->

4. Malfunctions of the ignition system: spark plugs, coils, wires

In gasoline engines poor starting is often associated with the ignition system. If the spark is weak or misses, the fuel mixture does not ignite in time, and the engine “troubles” when starting.

Main problems:

• ⚡ Spark plug wear — normal resource: 30–50 thousand km (regular) or 80–100 thousand km (iridium).
• 🔌 Breakdown of high-voltage wires — checked in the dark (sparks are visible).
• 🔥 Malfunction of ignition coils - one of the coils may “die” when cold.
• 📉 Incorrect gap between spark plug electrodes - should be 0.8–1.1 mm (check for your model).

How to diagnose? The easiest way is rearrange the spark plugs. If the problem “moves” to another cylinder, the spark plug is to blame. To check the coils you will need a multimeter (the resistance of the primary winding is 0.5–2 Ohms, the secondary winding is 6–15 kOhms).

⚠️ Attention: If by candlelight red plaque - this is a sign of bad gasoline with additives. If oil soot - problems with piston rings or valve stem seals.

How to check the spark without special tools?

Unscrew the spark plug, insert it into the high-voltage wire and apply it to the “ground” (for example, to the head of the block). Ask an assistant to turn the starter - if the spark is blue and stable, the spark plug is working. Be careful! Do not hold the candle with your hand - voltage up to 40 kV!

5. Sensors and electronics: why “brains” interfere with startup

Modern cars are equipped with dozens of sensors that determine the composition of the fuel mixture, ignition timing and other parameters. If at least one of them gives false readings, The ECU (electronic control unit) may “go astray” when starting.

Key sensors affecting launch:

• 🌡️ Coolant temperature sensor (DTOZH) — if it’s lying, the ECU incorrectly adjusts the mixture.
• 💨 Mass air flow sensor (MAF) - if there is a malfunction, the engine “chokes.”
• 🔄 Crankshaft position sensor (CPS) — without it, the engine will not start at all.
• 🚗 Throttle Position Sensor (TPS) - affects idle speed.

How to check? Connect a diagnostic scanner (for example, ELM327) and look error codes. For example:

• P0115 — DTOZh malfunction;
• P0100 — problem with the mass air flow sensor;
• P0335 - DPKV error.

If you don’t have a scanner, you can check the sensors with a multimeter (resistance, voltage). For example, a working DTOZh resistance at 20°C should be about 2–3 kOhm.

6. Mechanical problems: compression, timing belt, oil pump

If all previous systems are in order, but the engine is still takes a long time to “set” or works unevenly, mechanical faults may be to blame. They are less common, but their consequences are more serious.

What to check:

• 🔧 Compression in cylinders - if below normal (for example, less than 10 bar for a gasoline internal combustion engine), the mixture does not compress well.
• 🔄 Timing belt/chain — if it jumps 1-2 teeth, the valve timing is disrupted.
• 🛢️ Oil pump — when worn, it does not create the required pressure, the parts work “dry”.
• 🔥 Piston ring wear - leads to loss of compression and oil entering the combustion chamber.

How to diagnose? Compression is checked compression gauge (the norm for gasoline internal combustion engines is 12–14 bar, for diesel engines — 25–35 bar). If the variation in the cylinders is more than 1 bar, there is a problem with the rings or valves. The timing belt is visually inspected for cracks or chipped teeth.

⚠️ Attention: If the engine starts and immediately stalls, this could be a sign critical camshaft wear or valve failures. In this case, further exploitation is fraught motor jamming.

7. External factors: weather, fuel, driver errors

Sometimes the problem lies not in the car, but in external conditions. Here's what might be preventing it from starting:

• ❄️ Frost below −20°C — the oil thickens, the battery loses capacity, the diesel becomes waxy.
• ⛽ Bad fuel - diluted gasoline or “summer” diesel fuel in winter.
• 🚗 Clogged air filter — the engine “chokes” when starting.
• 🔑 Driver errors - for example, a handbrake not released or a gear engaged (for manual transmission).

How to prevent it?

• Use in winter synthetic oil with low temperature viscosity (for example, 5W-30).
• Fill up at trusted gas stations (avoid “no-name” chains).
• Before starting in cold weather, turn on the high beams for 10 seconds - this will “warm up” the battery.
• If the car has been sitting for more than a week, before starting Turn the ignition on and off 2–3 timesso that the pump pumps up fuel.

What to do if the engine does not start at all?

If the engine does not respond to turning the key or the starter turns, but the motor does not “grab”, follow the algorithm:

1. Check the battery: voltage, terminals, fuses.
2. Make sure there is fuel (yes, it happens too!).
3. Listen to the starter working: Clicks, grinding sounds, slow rotation.
4. Check fuses (especially those responsible for the fuel pump and ECU).
5. Inspect the candles — wet, dry, with soot?
6. Connect diagnostic scanner (if any) to find errors.

If all else fails, and you need the car urgently, call a tow truck. Do not try to “crank the starter until it wins”: this will drain the battery and may damage the solenoid relay.

FAQ: Frequently asked questions about long engine starts

❓ Why does the engine start badly when hot?

This is a typical problem for machines with worn piston rings or faulty fuel pump. When heated, the gaps in the parts increase, the compression drops, and the pump does not create the required pressure. The following may also be to blame:

• Temperature sensor (lying to your “brains” about a cold engine).
• Air leaks through cracks in the manifold.
• Faulty injectors (fuel is poured when hot).

❓ Is it possible to start a car with a discharged battery by “lighting up”?

Yes, but follow the rules:

1. Connect positive terminals donor and recipient.
2. Connect the donor minus to recipient weight (for example, to the engine block).
3. Get a donor and let it work for 5 minutes.
4. Try to have a recipient. If it doesn’t work, don’t torture the starter for more than 10 seconds.

⚠️ You can't light a cigarette while the engine is running. - this can damage the donor generator.

❓ How much does it cost to diagnose a long startup at a service station?

The cost depends on the type of diagnosis:

• Computer diagnostics (scanner + error checking) - 800–1500 ₽.
• Checking the battery and starter — 500–1000 ₽.
• Compression measurement — 1000–1500 ₽.
• Complete fuel system diagnostics — 2000–3000 ₽.

On average, a comprehensive audit costs 2500–4000 ₽.

❓ Why does diesel start badly in winter?

Main reasons:

• Summer diesel fuel — thickens at −10°C and clogs the filter.
• Faulty glow plugs - do not warm up the combustion chambers.
• Water in the fuel system — freezes and blocks the supply.
• Wear of fuel injection pump - does not create the required pressure when cold.

Solution: use antigel (for example, LIQUI MOLY Diesel Fliess-Fit), warm up the glow plugs 2–3 times before starting, refuel with “winter” diesel fuel (up to −30°C).

❓ Can bad gasoline cause a long start?

Absolutely! Diluted gasoline (for example, with water or kerosene) has a low octane number, which is why:

• The mixture ignites with a delay.
• The spark plugs are filled with fuel.
• The engine “troubles” after starting.

If you refueled at a dubious gas station and the car began to have difficulty starting - drain the fuel and flush the tank. As a last resort, dilute the “bad” gasoline high octane (for example, AI-98) in a 1:1 ratio.