Engine knocking sounds... Please help!
 

Hey everyone!
I really need your help guys! Many times I posted my questions on BMW forums and always got the right answers.

Anyway, here is the video where you can hear these strange knocking sounds coming from my 325i 2002 engine: http://www.youtube.com/watch?v=9A_-27nq3vE

It started yesterday after I changed the oil, oil filter, fixed valve gasket sealant, changed a boot on first coil and changed all the spark plugs.
The reason I had to open up the gasket is because I had a very bad oil leak into the first coil compartment. Turned out, my last mechanic did not properly place that rubber sealant piece on first three coils. So I fixed it and no more oil there now. Initially the car was misfiring really bad, so I thought that was the problem.

However, now the car misfiring even worse :( I got the denso irodium sprak plugs from Advance Auto Parts... They said that Bosch were discontinued (weird). Anyway, they told me that the gap in spark plugs should be 0.44, but then I found on the net that it should be only 0.32... I tried both combinations... But still a bad misfire and knocking noise.

And these are the codes that I have:
P0300
P0174
P1085
P1083
P1349
P1353
P1351
P0420

If you anyone had the same problem, please share your experience!
Thanks in advance!

sounds like a vacuum leak somewhere. the idle is pretty bad.
the knocking sound sounds like DISA or could be the engine backfiring.
also get yourself a set of NGK sparkplugs cuz they are OEM.

Vacuum leak if I had to take a guess. Happened to me once when I put on a new lower intake boot and it slipped off a bit. Only time I ever heard a sound like that. I could be wrong but I would check where a MAJOR vac leak could happen.

Thanks for your fast responses guys! I just changed the spark plugs to NGKs... but it didn't solve the problem :/

One of the guys at Auto Parts said that it is back firing too... I don't know what that means.. gonna do my research now.

I also suspect that vacuum leak. What are the places where the vacuum leak is possible besides intake boot and intake tube?

its back firing inside the intake manifold.
mostly either CCV or intake boot.

you didn't drop a bolt somewhere in there right? And what are the error codes, did you look them up?

Excuse my noob question... but what is CCV and where can I find it?

hehe that was my first reaction to that noise, like wtf did I left in there... But nah, I worked with gasket seals only, and the sounds comes out of the manifold.

I looked up all the codes! Most of them are about misfires. Others point to fuel mixture, vacuum leaks and O2 sensor.

So tomorrow I will definitely get to searching of vacuum leaks... Just wanted to get as many possible places where I can find them.

search

with all those codes, I put my money on vacuum leak.

Another thing that is really bugging me... Why all these started after my fixes. I mean, if I had this vacuum leak before, why it became this noticeably bad just now after I changed oil, sparks etc... Weird.

Just did lol Its an oil separator... Maybe the hose went bad...

its BMW. you will never have a problem free car.

oh god, how many times did I fix something and in the process discover something else that needs fixing, never ends

Just ordered intake boot and tube from my local dealer! Will go pick them up today and install right away! I hope that will solve my problems :hmm:

You mean "you will NOT have a problem free car"??? lol

just fixed it.:rolleyes:

Maan... I was hoping... Oh well.

Anyway, I just came from dealership with new intake boots. I really hope this will solve my problem. Also, one weird thing, when I started my car today, it was horrible... and the way to dealership was miserable... Every light my car was almost stalling... But after I left dealership on the way back, it was driving like nothing ever happened. Don't see any logic to that :hmm: I mean, if that was a leak, wouldn't it drive the same all the time?

LOL! how much did u pay dealer change your DUE old boots that's cost less then $20 and 10min of your time..

Also it would had been a lot cheaper to clean DISA,ICV with brake cleaner and replace lower+upper boots+ valve cover gasket can cause vaccum leak including then vaccum
Lines running from 2nd air pump to the back manifold

Hey, I did myself aright! lol I wish I had that much money to just go to dealership and let them fix it all...

But anyway, you guys want to laugh? I found the damn problem. The cover gasket is missing one of the bolt/studs with rubber thingy. So it is sucking in the air like crazy. Do you guys know any place online where I can buy it? Or part number?