[Pauly Mundo]

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Engine KNOCKING RATTLING at start up if you let go of the clutch to early
Hi. I would. Like to ask you all out their if any of you add this annoying problem noise i have found with my car .im on my second 3series touring having rote off the first one after three half year's from new i just got a new babe again 320d M Sport panoramic roof leather space gray ++.anyway
I found this problem ive been to my dealer few. Times they cant tell me what it is exactly,i found this by one day starting the car up and add to get something. From back seat and i Let go of the clutch pedal as it was starting up and i herd this VERY LOUD GRINDING RATTLING NOISE FROM ENGINE OR GEAR BOX like the engine was going to fall off the car i now can replicate the noise by letting go of the clutch pedal as the engine starts i know i shouldn't probably. Do that but i can't see why it makes that loud embracing noise and ive dune it at the at my bmw dealer and they tell me you should keep your foot on the clutch until engine is fully started im NOT HAPPY with this noise.and was wondering if anybody elseadd same problem or can try it on yours,im not very hi tec but ive made my self member in this Forum i find it very good and so helpfull. Also going to to record the noise and make a short video to put on youtube for other to see i dont think it should do this car isnt a year. Old yet and them telling me to keep foot on clutch peddle so it doesn't cause tension on the bering i dont think is a good excuse because the car does start without pressing. The cluch peddle on autostart when it rolls forward or when the battery voltage drops so dont get it .if anyone can help me . Many thanks Paulo

[seanblee]

It's probably the DMF. I don't have experience of them on BMWs, but I know on my diesel Focus that Ford put logic into the ECU to cut the engine if the revs fall too low to prevent DMF damage, so it wouldn't surprise me if it's noisy as the engine is catching. Is it noisy with the clutch pedal out at tickover from cold? If not, I don't think it's worth worrying about...

[Pauly Mundo]

No it does it all the time cold or hot i press clutch down to start the car up press the button and has it starts i let go of the clutch pedal straight away and hou get that big loud grinding ratelling noise from engine or gear box .

[seanblee]

OK, but I'm not sure I understand the issue. BMW has told you to keep your foot on the clutch until the engine is started and if you do that then there's no problem. If you ignore what the manufacturer tells you then you get an unpleasant noise. The car won't let you start it unless you have your foot on the clutch. What am I missing?

[doughboy]

I thought if you lift the clutch (in neutral obviously) during the engine cranking phase it will cut the starter motor, not continue cranking?

I know mine does it, sometimes I'm a bit quick off the clutch before the engine catches, and it just stops, no noises at all??

[xenon]

What's a DMF??

[seanblee]

Originally Posted by xenon

What's a DMF??

Dual Mass Flywheel - http://www.honestjohn.co.uk/faq/dual-mass-flywheels/

[Pauly Mundo]

Originally Posted by doughboy

I thought if you lift the clutch (in neutral obviously) during the engine cranking phase it will cut the starter motor, not continue cranking?

I know mine does it, sometimes I'm a bit quick off the clutch before the engine catches, and it just stops, no noises at all??

Hi yes in neutral as it starts if im quick off the pedal then it will start but it does make that loud cranking noise but the engine does not stop the sound is so bad it realy sounds like its dune some damage...i found that by unknowingly when i was reaching something. From back seat let go of the clutch and i dont think it shluld do that it should start normaly or cut .

[Pauly Mundo]

Originally Posted by seanblee

Dual Mass Flywheel - http://www.honestjohn.co.uk/faq/dual-mass-flywheels/

Hi thank you that gave me some understanding about dual-mass-flywhell
Still i think the noise cames from somewhere else it sounds quiet externaly

[Pauly Mundo]

Originally Posted by seanblee

OK, but I'm not sure I understand the issue. BMW has told you to keep your foot on the clutch until the engine is started and if you do that then there's no problem. If you ignore what the manufacturer tells you then you get an unpleasant noise. The car won't let you start it unless you have your foot on the clutch. What am I missing?

Hi yes you right i should keep my foot on clutch until it starts but needs to be some space. For human error!!! I happened to try grab something from the back. Seat and accidentally let go of the clutch and it made that loud rattling that made everyone look around me in town so sorry but for a 30K bmw no way this is an excuse..to keep foot on clutch.