What Causes the BMW 523 to Shake During Cold Starts?

[AveryAnn]

Cold start shaking may be caused by carbon deposits, weak ignition, low cylinder pressure, or substandard fuel. Reasons for cold start shaking: It could be due to excessive carbon buildup in the throttle body, fuel injectors, or intake manifold; mechanical failures in components like ignition coils, spark plugs, or fuel injectors leading to cylinder misfires; or insufficient power caused by low fuel pressure or cylinder pressure. Solutions: Shaking during cold starts is usually temporary and will disappear once the engine oil reaches the appropriate operating temperature. If the shaking persists, it is necessary to inspect the engine's condition, including the throttle body and spark plugs.

[LaKeegan]

I've encountered similar situations before. For cars like the BMW 523, cold start shaking usually has several common causes. The most common ones are aging spark plugs or ignition coil failure - when they can't ignite properly in low temperatures, the shaking becomes severe; carbon buildup in the throttle body affects the air-fuel mixture concentration, leading to unstable intake and consequently shaking; when engine oil has poor fluidity in cold conditions, insufficient oil supply from the oil pump also makes the engine tremble; insufficient fuel pump pressure or clogged fuel injectors can cause uneven fuel supply; and carbon deposits accumulating in the cylinders lead to incomplete combustion, exacerbating the shaking. For safety, I recommend first trying to replace the spark plugs and clean the throttle body. If it still shakes, then check if the ECU sensors are improperly calibrated - for example, a malfunctioning oxygen sensor could also cause problems. Don't neglect regular maintenance, especially using the right low-temperature engine oil can prevent this issue.

[ElliottMarie]

My 523 always shakes when starting cold, and after checking, there are quite a few possible reasons. It might be that the spark plugs are worn out—replacing them should fix it; if the throttle body is dirty, cleaning it will smooth things out; if the engine oil is too thick, it affects lubrication in cold weather—switching to a thinner oil like 0W-30 will immediately improve it; carbon buildup is common in city traffic jams, so regularly using carbon cleaner can prevent it; a failing fuel pump or clogged fuel filter can also cause shaking. When doing it yourself, pay attention to safety—don’t randomly disconnect sensor wiring. Additionally, worn engine mounts can amplify the shaking sensation, so they need to be checked and replaced. Always listen to your car’s sounds to catch issues early, and maintain it well to avoid trouble.

[DeCassandra]

I've encountered cold start shaking a few times while driving a BMW 523. Common causes include worn spark plugs or a dirty throttle body, especially when excessive carbon buildup leads to uneven air intake and vibration; poor oil fluidity at low temperatures is another key factor; fuel system issues like clogged injectors can cause mixture imbalance and shaking. A simple solution is regular cleaning or part replacement, which usually alleviates the problem.