Strange sounds from around the BMW pedals – how to fix it?

BMW driver’s question

For the past few days, every time I start the vehicle on a cold engine, it makes strange sounds that are hard to locate. It seems to me that they are coming from the area around the pedals/under the steering wheel. The car fires up, for the first 5-6 seconds you hear this sound and everything returns to normal, the car runs properly, no loss of power, no shaking, everything is fine.

These sounds are accompanied by a slight longer “spinning” before the car starts. On a warm engine the symptoms do not occur, the car fires up quietly and smoothly like new – every time. Last time I had a problem with similar sounds after firing up, they stopped after replacing the fuel filter.

The sounds from the fuel filter were purely “electronic”, the current problem sounds more like a mechanical dinging of two components. The problem is illustrated by the two videos below, which I recorded. The sound in question is loud, clearly heard by passersby.

Is there a shadow of a chance that this is again the fault of a faulty fuel filter, this time making a different sound? Perhaps you have encountered this characteristic sound before?

The problem affected a BMW 3 E46 with a 2.5i M54 engine without an LPG system, but it can also happen in other models.

Footage provided by the owner of the BMW

Response from BM Cars service

The described engine start-up noise problems are very difficult to diagnose without a visual inspection of the car. Trying to diagnose based on the uploaded recordings is not possible. The first step is to determine approximately where the sound is coming from.

If it is near the bulkhead wall (pedals or space under the steering wheel), it may be related to the exhaust system mount – the first hanger. The moment of starting a cold engine is always associated with increased vibration transmitted from the engine to the body. If, in addition, there was a problem with prolonged spinning of the starter, before starting the engine, then this can cause the transmission of increased vibration to the exhaust system.

If there is a problem with the first hanger of the exhaust system (sintered or broken rubber hangers) or with the increased tension of the exhaust mounting parts – this can cause noises until the engine reaches increased RPM and aligned operation.

Associating the source of the sound coming from around the engine with the replacement of the fuel filter is completely coincidental. The fuel filter in the BMW 325i E46 is equipped with a pressure regulator, but it does not make any sounds during operation.

We suggest the following solutions:

1. Determining the location of the sounds – starting the engine on a jack.
2. Identification of the faulty components.
3. Removal of the defect.

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