The LSPI problem

Date: Monday 08 August 2022

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LSPI has been rife throughout the industry for years – low speed pre-ignition. It can lead to engine knocking, especially in new car models, thereby causing serious engine damage. But you don’t have to accept this – thanks to the additive specialist LIQUI MOLY.

Modern high-compression engines with direct injection are at an increased risk of premature ignition at low speeds (LSPI – low speed pre-ignition): the fuel-air mixture in the combustion chamber ignites before the ignition spark is produced. This knocking can result in serious engine damage. It is a phenomenon that is not yet fully understood, but contamination inside the engine definitely has a part to play.

This can be done in two ways: First of all, in the selection of the engine oil. Modern motor oils have an adapted formulation to reduce the risk of LSPI. Anyone trying to save money on oil can end up paying much more later in the event of engine damage. With just a few clicks, the free oil guide at www.liqui-moly.com tells you exactly which oils are the right ones for a particular vehicle.

The second point is the DFI Cleaner by LIQUI MOLY. This is a special cleaning additive that is poured into the fuel tank. It contains polyetheramine (PEA) as an active ingredient.

“Active PEA is a highly effective cleaning chemical that removes even stubborn deposits on the injectors, pistons and combustion chamber,” explains David Kaiser, Head of Research and Development at LIQUI MOLY. “When used regularly, it provides permanent protection from new carbon deposits, too.”

These deposits are considered an essential factor in connection with LSPI. The injection systems in modern, direct-injection turbocharged petrol engines are subject to high levels of stress. The injection nozzles extend directly into the combustion chamber, so they are exposed to high temperatures, pressures and the impact of combustion residues. Deposits form at the nozzle outlets within a short time, resulting in the petrol no longer being atomised so finely. This impacts negatively on exhaust gas levels and increases fuel consumption. The deposits can begin to glow due to the high temperatures, which can result in engine knocking.

The DFI cleaner can be added at any inspection. It is so effective that it does not need to be added more than every 5,000 kilometres. It is suitable for all cars with a 4-stroke petrol engine, both for direct injection and cars with intake manifold injection.

LIQUI MOLY has more than 60 years of experience of additives and is the market leader in Germany.

“Additives are useful chemical tools,” says David Kaiser. “They can solve a lot of problems more quickly, more easily and more cost-effectively than mechanical attempts.”

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