[beem]

Hi all,

First post here...I hope I could gather some opinions on what is wrong with my car (320i N46). Been having this harsh vibration on my car...although the RPM seems stable..hovering at 700rpm with the aircond on but the engine seems to be vibrating harshly compared to other cars and it can be felt throughout the cabin. Took it to the dealership...everything tested normal (including compression test) except for the rough running cylinder test at the innermost cylinder (closest to the windscreen)...marginally passing...about -3.15. They have no idea what to do next either....

plugs changed. coils changed. oil separator changed. cleaned contacts on injectors. changed fuel filter. changed air filter.

I'm really saddened...

[astra]

Hey Beem, welcome to the forum

It's a new car... I'd take it back in, and have them have another look (but take it to a different dealer this time), and see whay happens then?

Sounds like you have exhausted most of the usual suspects though... GL with figuring out the issue though

[beem]

I was thinking of cleaning the injectors...any thoughts?

Or maybe cleaning the contacts on the inner cylinder ignition coils?

[beem]

Anybody could help shed some light here?

[VGR00]

Sounds like the dealer has gone though the main parts that would present a problem. How many Klms have you got on the car ???. Maybe an injector clean is worth a try especially if you suspect you have had some dodgy fuel in the past. You haven't mentioned but I'm assuming the dealer has re-flashed the ECU??. If not, then I'd demand they do that. As a last resort maybe they need to swap out the ECU.

Hope you get sorted quickly.

[beem]

The car has travelled slightly over 70K kms. ECU has been reflashed. They have tried swapping the ECU with another car but it doesn't help.....I have not tried the injector cleaning yet...was going to do that next...

[VGR00]

OK .... I had this on a 6 cyl 320i once and it turned out to be a faulty coil. Even though it tested fine, the coil was faulty. You need to replace them all to ensure the inductance is constant but if you want to save money try buying one and replace one at a time till you find the bad coil.

[beem]

Inductance....didn't cross my mind....

However, I tried swapping coils between cylinders..the fault still lies in the 4th cylinder....that happened to u as well until u replaced all 4?

[VGR00]

No ... if the fault was in the coil then the 4th cylinder would have been running well and the other played up. Sorry ... I'm out of suggestions for you.

[beem]

Thanks man.....even the dealer is out of suggestions tooo........

[henry2703]

have you thot of getting the engine mount checked?

In singapore we have quite a few 320i with vibrating engines, after roughly about 70k mileage. An engine mount change fixed the problem.

[beem]

Engine mounts were changed too...sadly, the rough running values have not changed...