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Difficult start (gasoline engine)

4 Solutions for Difficult Gasoline Engine Start

In cold weather, gasoline engines often struggle to start. This is usually caused by improper combustion of the fuel-air mixture, starter motor issues, or fuel system contamination. Difficult starting can lead to battery drain, increased wear, and frustration for drivers. In this guide, we’ll outline 4 solutions to make starting easier and show how XADO products help restore reliability.

Understanding the root causes of starting problems is essential. Cold temperatures thicken oil, reduce fuel vaporisation, and expose weaknesses in ignition systems. By addressing these factors proactively, you can avoid costly repairs and ensure dependable winter performance.

Solution 1: Use Quick START spray

Quick START spray contains special compounds that make ignition easier. Spray a small amount into the air filter or intake collector before starting. This is especially useful in winter when fuel vaporisation is poor, and the mixture struggles to ignite.

The spray provides a temporary boost, helping the engine fire up quickly. It is safe for all gasoline engines and does not harm catalytic converters. Drivers often keep a can in the glove box during winter months as an emergency aid.

Solution 2: Clean the fuel system

Deposits in the fuel system reduce combustion efficiency. Over time, varnish and carbon build up inside injectors, restricting flow and causing poor atomisation. Preventive cleaning with AtomEX Multicleaner before winter ensures smooth fuel delivery and better cold starts.

A clean fuel system improves throttle response, reduces emissions, and restores lost power. Regular use of AtomEX Multicleaner keeps injectors free from deposits and maintains consistent spray patterns, which are critical for reliable ignition.

Solution 3: Use low-viscosity motor oil

At low temperatures, thick oil increases resistance and makes cranking harder. Switching to SAE 0W-30 or 5W-30 oils for winter reduces strain on the starter motor and battery. The number before “W” indicates cold-temperature properties — lower numbers mean easier starting.

Low-viscosity oils also improve lubrication during cold starts, reducing wear on moving parts. This is particularly important for older engines, where wear tolerance is lower. Choosing the right oil ensures smoother operation and extends engine life.

Solution 4: Protect spark plug wires

Moisture and frost can interfere with spark plug connections, leading to misfires and weak ignition. Apply a Universal Silicone Lubricant to spark plug wires and points to prevent moisture ingress and ensure reliable spark delivery.

Protecting ignition components is a simple but effective step. Silicone lubricants also extend the life of rubber parts, preventing cracking and hardening in cold weather. This small preventive measure can make a big difference in starting reliability.

Additional preventive tips

  • Check battery health before winter — weak batteries struggle in cold conditions.
  • Inspect starter motor connections for corrosion or loose terminals.
  • Keep fuel tank at least half full to reduce condensation and water contamination.
  • Service spark plugs regularly to maintain strong ignition.

Recommended products

XADO Petrol Multi cleaner used to clean injectors to fix difficult gasoline engine start in cold weather

Properties

  1. Makes the engine start easier in cold weather
  2. Restores worn engines and prevents further wear
  3. Safe for all gasoline engines
  4. Improves fuel economy and reduces emissions

Application instructions

Add AtomEX Multicleaner to the fuel tank before refueling. Drive normally to allow the cleaner to circulate and dissolve deposits. Repeat every 3,000–5,000 miles for preventive maintenance.

For related issues, see our Condensed Water under Tank Cap blog. You can also explore preventive solutions in our Engine Smoking blog.

For background on cold starting systems, see this technical overview of starter motors.

Conclusion

Difficult gasoline engine starts in winter are preventable. By using Quick START spray, cleaning the fuel system, switching to low-viscosity oil, and protecting spark plug wires, you can ensure reliable ignition even in cold conditions. Combined with regular maintenance and preventive checks, XADO solutions keep your engine efficient, dependable, and ready for winter challenges.

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