2009 E90 BMW noise when accelerating. Please help!
Discussion
Car type: 2009 318d BMW M sport Saloon (auto).
Mileage: 90k
I am hoping someone can help me identify this noise/fault that is coming from underneath my car. It has been plaguing me for over a year & has still not been located even after visiting two BMW specialists in the Midlands area.
A little background; I had a major service done on my drive last year with a mobile mechanic (fuel filter, pollen filter, air filter & oil filter were changed, MANN branded). Immediately after this my car started making the noise.
It is most evident when accelerating from a standstill, going uphill or anytime the car is put under a little bit of strain. The engine will rev & when it gets towards the end of gear one a sound will emit from under the car. Sometime the noise is repeated as I’m going through the gears (gears 1,2 & 3). The sound can be heard even with the windows closed.
I took it to two independent BMW specialists & the following was checked when trying to locate/diagnose the noise:
BMW Specialist one (Birmingham):
• Test drive (sound was heard briefly by mechanic)
• Under covers
• Heat shields
• Exhaust
• Propeller shaft
• Engine and gearbox mounts
• Fuel filter if not properly fitted from before
• Flexi-pipe a bit damaged but not source of noise
This garage after trying to diagnose admitted defeat & said they could not find the fault. They did however say my flexi-pipe was damaged but not the source of the noise.
BMW specialist two (West Midlands):
• Test drive (sound was heard numerous times by mechanic)
• Flexi-pipe is damaged & is the source of the problem/noise. The pipe was apparently hitting the under carriage thus making the sound.
The mechanic heard the sound numerous times during the test drive. When putting it on the ramp he concluded it was the flexi pipe & repairing this would resolve the issue.
I had the repairs done at an exhaust & welding specialist hoping this would fix the issue but unfortunately the sound is still there.
Recording:
The sound can be heard towards the end of the recording between 42 – 44 seconds (sound is audible straight after engine revving). The “kuchuck” noise can be heard twice.
https://vocaroo.com/i/s0N5PaDv4Ci9
Mileage: 90k
I am hoping someone can help me identify this noise/fault that is coming from underneath my car. It has been plaguing me for over a year & has still not been located even after visiting two BMW specialists in the Midlands area.
A little background; I had a major service done on my drive last year with a mobile mechanic (fuel filter, pollen filter, air filter & oil filter were changed, MANN branded). Immediately after this my car started making the noise.
It is most evident when accelerating from a standstill, going uphill or anytime the car is put under a little bit of strain. The engine will rev & when it gets towards the end of gear one a sound will emit from under the car. Sometime the noise is repeated as I’m going through the gears (gears 1,2 & 3). The sound can be heard even with the windows closed.
I took it to two independent BMW specialists & the following was checked when trying to locate/diagnose the noise:
BMW Specialist one (Birmingham):
• Test drive (sound was heard briefly by mechanic)
• Under covers
• Heat shields
• Exhaust
• Propeller shaft
• Engine and gearbox mounts
• Fuel filter if not properly fitted from before
• Flexi-pipe a bit damaged but not source of noise
This garage after trying to diagnose admitted defeat & said they could not find the fault. They did however say my flexi-pipe was damaged but not the source of the noise.
BMW specialist two (West Midlands):
• Test drive (sound was heard numerous times by mechanic)
• Flexi-pipe is damaged & is the source of the problem/noise. The pipe was apparently hitting the under carriage thus making the sound.
The mechanic heard the sound numerous times during the test drive. When putting it on the ramp he concluded it was the flexi pipe & repairing this would resolve the issue.
I had the repairs done at an exhaust & welding specialist hoping this would fix the issue but unfortunately the sound is still there.
Recording:
The sound can be heard towards the end of the recording between 42 – 44 seconds (sound is audible straight after engine revving). The “kuchuck” noise can be heard twice.
https://vocaroo.com/i/s0N5PaDv4Ci9
For the whole of the recording, is that hissing sound an air induction leak, or just air passing the microphone ?
That aside, has that model got an active exhaust valve for recirculating gases (EGR) ? It’s the kind of noise I might get at work, when the valve is being tested, during a cleardown.
That aside, has that model got an active exhaust valve for recirculating gases (EGR) ? It’s the kind of noise I might get at work, when the valve is being tested, during a cleardown.
Edited by RUSSELLM on Thursday 27th June 14:34
redchief said:
Many thanks for the response.
The sound you are most likely hearing is indeed traffic/wind noise, I had the windows down.
The noise in question can be heard after 40secs, immediately after the engine rev sound.
I am unsure if it has an EGR valve, how do I check?
Go onto the RealOEM website; put the last 7 digits of your VIN into the box at the top of the page and it'll bring up your exact carThe sound you are most likely hearing is indeed traffic/wind noise, I had the windows down.
The noise in question can be heard after 40secs, immediately after the engine rev sound.
I am unsure if it has an EGR valve, how do I check?
Look through the diagrams and it'll tell you whether your engine has the EGR fitted (IIRC I thought all diesels did, just not all had the DPF fitted); could be wrong though... It's been known to happen
I’ve a feeling it’s going to be in the engine bay, on your car.
However, follow the exhaust from the rear, and see if there’s anything plugged in, that doesn’t look like an O2 sensor or temperature sensor.
If the garage couldn’t find the source of the sound when they were stood under the running car, i’m guessing it’s only happening under load ?
However, follow the exhaust from the rear, and see if there’s anything plugged in, that doesn’t look like an O2 sensor or temperature sensor.
If the garage couldn’t find the source of the sound when they were stood under the running car, i’m guessing it’s only happening under load ?
Issue has now been solved!
I took it back to the second specialist again & this time a different mechanic had a look. Again I mentioned the noise started immediately after the service & to perhaps look at the components that were changed. Another stint on the ramp & numerous revs later he had a look at the air filter & found the turbo intake pipe that is attached to it wasn't clipped on properly!
Not only has the noise totally gone the car now sounds completely different (for the better).
Not sure if I am allowed to mention the garage buts its a well known BMW specialist in Redditch, West Midlands. It is however a little unfortunate they misdiagnosed it initially.
I took it back to the second specialist again & this time a different mechanic had a look. Again I mentioned the noise started immediately after the service & to perhaps look at the components that were changed. Another stint on the ramp & numerous revs later he had a look at the air filter & found the turbo intake pipe that is attached to it wasn't clipped on properly!
Not only has the noise totally gone the car now sounds completely different (for the better).
Not sure if I am allowed to mention the garage buts its a well known BMW specialist in Redditch, West Midlands. It is however a little unfortunate they misdiagnosed it initially.
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