Banging, running like shit!!

[MattM]

this has been pissing me off and i cannot find what it is. The random non rythmic metallic banging

1997 M52 running full obd2.

Facts:

- compression is 195-200 on all cylinders
- Camshafts are in good shape
- nothing obviously loose in the head
- nothing obviously loose in the bottom end
- No engine codes

http://www.youtube.com/watch?v=ZU3AFGxtol4

[sohc12vm20]

this has been pissing me off and i cannot find what it is. The random non rythmic metallic banging

1997 M52 running full obd2.

Facts:

- compression is 195-200 on all cylinders
- Camshafts are in good shape
- nothing obviously loose in the head
- nothing obviously loose in the bottom end
- No engine codes


http://www.youtube.com/watch?v=ZU3AFGxtol4

OK I'm just giving my opinion here.. Diffidently doesn't seem/sound mechanical. I just finished my s52 obd1 swap and it sounded and idled exactly the same, my dumb ass rushing to get the car started I ended up putting the MAF in backwards.. You know I hate admitting this publicly.. I would think it should throw a code or something. Hows the fuel pressure? Fuel lines correct?

[MattM]

OK I'm just giving my opinion here.. Diffidently doesn't seem/sound mechanical. I just finished my s52 obd1 swap and it sounded and idled exactly the same, my dumb ass rushing to get the car started I ended up putting the MAF in backwards.. You know I hate admitting this publicly.. I would think it should throw a code or something. Hows the fuel pressure? Fuel lines correct?

You dont think it sounds mechanical?

Its a metal on metal banging noise

Ive rotated through 2 MAF's and the results dont change

Fuel pressure is steady 51 psi

Fuel lines are correct

[scottinAZ]

Timing chain tensioners all in good condition?? if the idle is very erratic, and there is slop in the chains, you would get a noise similar to what you are hearing. Chances are if you get the idle under control, the noise will go away (engine isnt kicking back against the chains, causing them to rattle)

[MattM]

chains are tight. Ive now pulled the valve cover off again.

[Beej '86 325es]

Matt, that issue I PM'd you about last week I ended up solving. My car was running horribly, to the point that I couldn't keep it running unless I gave it a lot of throttle. My new MAF ended up being bad. Did you try unplugging your MAF?

[MattM]

when i unplug the MAf the car at least stays running.... but it still bangs

[e46s54dr]

Did you pull the head and do anything with the timing? I want to say it sounds more like an incorrect timed misfire than it does mechanical. Maybe its just the sound distortion on the video?

[MattM]

I havent touched anything deeper then the valve cover.

Its a very metallic banging noise

[e46s54dr]

If you are pretty sure its coming from the bottom end then I suggest your drain the oil first to look for any type of metal shavings or anything odd. Then you should remove the oil pan and have a visual inspection followed by rotating your crank manually to see if anything unusual happens during the crank rotation. I know it sucks balls but thats the best thing to do to avaoid any further damage if there is indeed something mechanically wrong.

[sohc12vm20]

You dont think it sounds mechanical?

Its a metal on metal banging noise

Ive rotated through 2 MAF's and the results dont change

Fuel pressure is steady 51 psi

Fuel lines are correct

I don't think its mechanical.. From what I could hear on me work computer.. Your ignition coils are fine? Ive heard a few of these engines make knocking sounds with faulty ignition coils. However they did maintain a some what steady idle. My guess would have been the MAF, but if you've already address this, that's also true, engine could be out of timing.

[sohc12vm20]

Just to add, a week after I bought my M5 I went to start it and it cranked and died.. I went to start it again and the car could barely idle almost seemed like the engine was about to blow. So I find out apparently the engine had a faulty timing chain tensioner and so when I went to start it the 2nd time the chain had already jump forward. Heck I thought the engine was done. Anyhow of course car was under warranty and was fixed by BMW.

[MattM]

disconnecting the maf makes it idle somewhat steady, but it still bangs and clanks around... i notice with the maf unplugged there is a slight dip in the idle right before it bangs

[DesertBMW]

To me sounds like low rpm pre-ignition and forces the piston slap to rattle in its bore causing loud mechanical knock. Maybe you mixed the coil connectors because ignition timing is off.
Noise is random, if the noise was rhythmic and constant then I would believe that there is something lose in the engine.

This person has the same problem but it is do to worn engine bore and not wrong timing:

http://www.youtube.com/watch?v=6aMqUvx818k&feature=related

[e30rapidic]

I'm thinking you have 2 or more coil connectors wrong as well