Need help with startup noise: rattle/zip ***Solved***

[ClubSport]

I've got a 95 M42 with 85k on the clock that makes an annoying noise on cold startups.  Not that cold either - anything lower than about 60F.  As soon as it cranks and you let off the key it makes a rattling/zipping sound like the timing chain or something, but only for about 2 seconds.  If you turn it off immediately and crank it again, it'll do it again, but if you let it warm up and make a warm start there's no noise.  I tried upgrading to the M44 tensioner and followed the startup procedure with no luck.  I've tried every oil from 0W-30 to 20W-50 with no change.  The only thing that helps really is to give it some gas during cranking and get the rpms up right away at startup.
Anybody got any ideas? Starter maybe? Chain?

[roelpeeters]

I have got exactly the same problem, when you look at the oil pressure light does it make the sound rougly as long as the light is on?

mine does, and this to me is an indication that the tensioner is loosing its pressure over time when not running.

does anyone whether the tensioner is supposed to stay pressurised?

[ClubSport]

Need to bump this thread.  Still got the dang noise and it's driving me nuts!

[nicknikolovski]

Can you post a video? The tensioner should retain some oil but the chain should remain lubricated with oil all the time. The oil lubrication system starts pressurizing while the engine is cranking so when it fires it is ready and pressure is stable for idle.

I would think about checking oil pressure and maybe inspecting some of the chain guides.

[ClubSport]

http://www.m42club.com/forums/showthread.php?p=68378

This sounds a lot like my noise. I'll have to check into the starter and see if I can get a sound clip.

[mjnov]

sounds like oil pressure.. try put a bit of extra oil in.. few ml above the full mark... see if that makes a diference. i had that noise.... like a rattle.... bit off acceleration (oil pressure) and it didnt do it

[ClubSport]

I forgot to get back to y'all on this one, but it turned out to be the starter.  I took it out, took it apart and cleaned the gunk, dust and grit out of the gears and solenoid.  Then I put some new grease on the internal gears only and put it back in.  No noise!  Several cold starts now and no chatter.  I guess the solenoid was not retracting hard enough to pull the gear out of the flywheel so it made noise when the flywheel overran it.