Rattle from engine on throttle tip in?

jabela · 03-27-2012, 03:00 PM

Any ideas what that rattle sound is? It only occurs on throttle tip in. I've noticed it happening anywhere between 700-3000 rpm, when I go from zero throttle to a quick increase. I seem to be hearing it more often than before. I used to only hear it when adding throttle at very low rpm, like under 1000rpm under load (like going from coasting to accelerating). My car is an '02 and has 150K KM.
This video is after a long drive with the engine warmed up.
http://www.youtube.com/watch?v=y_dp17LuIDg
You'll hear a rattle when I hit the throttle.
Here's another audio sample
http://www.youtube.com/watch?v=vyH_6ciBAMs

Could it be the VANOS rattling? I already have the VANOS seal repair kit, but not the rattle repair kit.
It doesn't sound like the VANOS rattles that I've heard
http://www.youtube.com/watch?v=HRM7I2nHeMs
http://www.beisansystems.com/procedu..._procedure.htm

Could it be a loose timing chain?

SiR · 03-28-2012, 12:56 PM

doenst sound like vanos.

sounds kinda normal lol.

almost has the same sound of a car that wont turn off(think friday the movie when it car wont turn off lol (not the banging sound. you can hear the rattle. very similar sound)

http://www.youtube.com/watch?v=q_t1Sv_JG0A&t=135s

like the engine is torquing and its the header rattling on something.

almost a rod knock LIKE sound(im not saying its rod knock but its similar for that brief moment)... could be a bearing on something spinning that makes some noise under the quick hard rev up?

dont know what it could be...but I wouldnt worry about it unless it gets worse.

jabela · 03-28-2012, 04:08 PM

yea, it does sound like that clunking.
It has become a little worse so I am a little worried. I would like to catch the problem before it becomes catastrophic.
I used to only notice it if I was coasting in gear at very low RPM (like 1000-1500) then if I got on the throttle, it would clunk a little. Now it seems to happen more often, and if I rev it while stopped like in the video.

jrat59 · 03-28-2012, 04:14 PM

Check the tensioners... had the same issue on my 330ci, just needed alittle tightening... belts stretch and loosen up...

check that out, wouldnt be suprised if thats all it was.

jabela · 03-28-2012, 05:25 PM

Quote:

Originally Posted by jrat59

Check the tensioners... had the same issue on my 330ci, just needed alittle tightening... belts stretch and loosen up...

check that out, wouldnt be suprised if thats all it was.

Good idea... I didn't know the tension was adjustable though. How do you adjust it? I know how to loosen it but that's only temporary for putting the belt on/off.

JINT · 03-29-2012, 01:13 AM

could be detonation, you using good gas?

jabela · 03-29-2012, 11:06 AM

Quote:

Originally Posted by JINT

could be detonation, you using good gas?

Yup, always use Shell 91. I also tried some octane boost/injector cleaner to no avail.

Any suggestions on determining if it is a loose chain? Presumably the plastic chain guide has worn?

Other ideas are a bad DISA valve, bad accessory pulley (water pump, power steering pump, alternator, etc), loose exhaust shield.

jabela · 05-04-2012, 11:07 AM

So far it seems like it only happens when the engine is warmed up. I can't seem to make it happen when it's cold.
I also don't think it's the DISA, as it idles fine and I don't hear any noises from there.
The rattle seems to be coming from the cams/VANOS.

Here's some more samples.
I set the camera on the engine, hence some vibration noises, but none of the rattling I'm concerned with. The engine was cold, so I didn't hear any rattling. I basically just played with the throttle for a bit.
http://www.youtube.com/watch?v=-bnmL94K2hE

Here's one where I don't think there are any abnormal sounds.
http://www.youtube.com/watch?v=tK_Cs1lqG8A

**T.Dot_E30** · 05-04-2012, 11:18 AM

Hmm it sounds alot like ignition rattle to me. But that should only happen on engines with a distributor where timing is off. With coil packs, the ecu controls timing.

How are your injectors, sparkplugs etc? Maybe try something like seafoam or those kinda things that are suppose to clean out the system? Maybe it's buildup somewhere, or dirty injectors not spraying as they should. Not sure just throwing out ideas. My first guess was that it was related to lower grade gas and the engine is retarding timing, but since your on shell 91 it must be something else...

Either way, I don't think it is any catastrophic, it wouldn't cause your engine to fail. At least that won't be the reason for it.

ECU throws extra fuel during cold start, so that cold be why it runs fine during cold starts, but when it goes to normal mapping there seems to be something that is off either in the mixture, timing or something. That's my theory anyway...

jabela · 05-04-2012, 11:32 AM

My concern is that is seems to be getting more prevalent (or maybe I'm just noticing it more).
I'm not getting any codes, and it's odd that it only happens when the engine is warm. Maybe it is just the VANOS seals and they only rattle when the oil is warm and thinner.
It's not just the initial cold phase where the idle is high that it doesn't happen. Even after several minutes it doesn't happen. It only seems to happen after a good drive where the oil has time to get up to temp.
I have the new beisan seals, but I didn't get the new metal rings since the rattle is different from the typical vanos rattle. I still need to get the gasket and everything.
http://www.beisansystems.com/procedu..._procedure.htm

BmW1819 · 05-04-2012, 10:26 PM

that's your car pinging

how many km u have?? send me a pm

jabela · 05-07-2012, 11:25 AM

Quote:

Originally Posted by BmW1819

that's your car pinging

how many km u have?? send me a pm

Are you sure? It doesn't sound like engine knock that I've heard before. I suppose a good test would be to boost the octane of my gas with some octane booster to see if that clears it up. Right?

Also, wouldn't the knock sensors detect the condition and throw an engine code? I have no codes.

BmW1819 · 05-07-2012, 09:06 PM

No pull your plugs and look inside the cylinders i had same problem with my car small oil depots on top of the pistons

jabela · 05-08-2012, 08:23 PM

Quote:

Originally Posted by BmW1819

No pull your plugs and look inside the cylinders i had same problem with my car small oil depots on top of the pistons

Do you mean carbon deposits? It would be a good idea to pull the spark plugs and inspect them and the cylinder. I'll try to do that ASAP.
What did you end up doing to fix your issue?
I have 150,000KM on my car, 85% highway.

BmW1819 · 05-08-2012, 08:49 PM

sea foam or combustion cleaner at any auto part store