Rattle/knock at 3000 rpm 3.0R-B

[Blake8828]

Hi, this is my first post and I am the new owner of a my06 3.0R-B 6sp.
Sorry if there is already a topic on this, have done a search and found
nothing matching what happens.

If I accelerate gently in second gear at around 2800 RPM to 4000 RPM I
can hear a rattle/knocking noise coming from the engine/front end of
the car. The rattle/knock is in time with the rumble the boxer engine
makes. If I accelerate hard there is no rattle or knock. There is no loss
of power or delay in acceleration.

Just wondering if this is something to worry about? Happens in other gears
at the same RPM but is less noticeable. Also, I can't physically feel any
vibrations from this, can only hear it. Hoping it's not detonation!

I have scanned the ECU and no codes have come up, I have also reset the
ECU (disconnect battery for an hour) to no effect.

Any suggestions would be great!

Cheers.

[Kekotic]

What are you using to grab the codes? you might be able to get a learning view snapshot and check your timing to see where it's knocking.

[Blake8828]

I'm just using the 'Torque' android app. Seems to work, unplugged the MAF just to make the engine light come on
and it read the fault fine and cleared it.

Do you know what sort of timing advance these engine should be running?

Thanks

[KiDo_Tuning]

EZ30 timing chain tensioner is likely culprit, sounds like knock but slightly different noise like changing gears on mountain bike?

[Blake8828]

Not quite a mountain bike noise noise, more like a top-load washing machine when it is over loaded and becomes unbalanced.
If that isn't a too obscure analogy . When I think mountain bike, I think of a "ting ting ting ting" sound when the gears
change, though I don't ride much!

Does kind of make sense though, I assume under light acceleration the oil pressure is much lower, therefore, the hydraulic
tensioner can't push as hard on the chain... Just strange it doesn't happen at even lower RPM where the pressure would be
lower again.

Is this bad for the engine, or is the solution to drive with my foot flat to the floor to stop it happening?

I am quite interested in getting my car tuned by KiDo, do you think that would have any effect on the noise? Also, I emailed
sales@kido-racing.com.au last week inquiring about a tune for my car. haven't had a reply yet, wondering if this is still the
correct email? I am also quite happy for you to PM me details on this forum too .

[Blake8828]

I just went for another drive to listen to the noise more and try to explain it better.

It is worst in second gear, doesn't happen under fast or medium acceleration, only happens
when the accelerator is very lightly pushed. The engine makes a sound like when the high
lift cams kick in... This time I could feel a slight vibration in time with the sound.

Not sure if this extra info helps, just to clarify how lightly i'm acceleration imagine taking
about 10 seconds to go from 3000rpm to 4000rpm.

[Robbks]

Does the noise only happen at specific certain RPM.
or does it happen for that entire 2800-4000rpm range?

My car (06 3RB 6sp) used to have the TC rattle at around 2500rpm, but since it's been tuned it's no longer there.
Matt has obviously done some fiddling with the AVCS tables to stop it.

Do you run 98RON fuel only?
the stock maps have far too much ignition advance and these engine ping their heads off even on 98RON fuel.

Also, It sounds suspiciously to me like an exhaust leak or timing chain tensioner issue.

leave the car parked and have someone rev it up for you to see if the rattle is still there from behind the timing covers (use a long handled screwdriver as a stethescope)
or listen for exhaust leaks

[Blake8828]

It happens over the entire range of 2800-4000 rpm, though it is worst at about 3200 rpm.
The sounds kind of fades in then fades out.

Yep, only 98. Even tried 100. didn't seem to make a difference.

Will do, i'll try that tonight.

The noise isn't really that annoying just want to make sure its not causing damage!

Thanks for your help.

[jay.ritchie]

I previously had a timing chain issue too, it was only at idle and sounded like a "ch ch ch ch ch"- not deep, pretty high pitched.
Post a video/sound clip of the noise and someone will be able to tell you what it is!

[Blake8828]

That's a pretty good idea, hopefully the crummy microphone on my phone picks it up properly.
I'll record a video as soon as Ballarat decides that it has had enough rain.

[jay.ritchie]

That's a pretty good idea, hopefully the crummy microphone on my phone picks it up properly.
I'll record a video as soon as Ballarat decides that it has had enough rain.

[Blake8828]

Okay, so I tried to film it but the results were terrible, phones microphone is super sensitive to road noise
so it sounds like i'm doing 200 km/h at 20 km/h.

Although testing it more and more it seems that most the noise is actually at 2500 rpm (sorry, I know it sounds like I Keep
changing my mind!). Which makes me think back to Robbks' post....

My car (06 3RB 6sp) used to have the TC rattle at around 2500rpm, but since it's been tuned it's no longer there.
Matt has obviously done some fiddling with the AVCS tables to stop it.

In 4th gear at 60 km/h the car is at 2500 rpm and makes the noise constantly, always have to put the car in 5th. Only noticed
that is was the same noise today though. I've only had the car a short period of time and haven't had much time to dive it.

What kind of sound did your car make before the tune Robbks?

[Robbks]

mine was only a quick "tick" noise.

what happens is when i was cruising along the flat in 5th at that 2400rpm, with constant throttle it was silent.
but when I'd squeeze the throttle for a bit of uphill, you would hear a quick "tick tick tick" and that was it.
It sounded like the engine pinging, but when we logged it, there was no knock recorded.
So it was in fact the AVCS activation causing timing chain rattle.

[SubMeister]

@robbks

And what did Matt do to sort it out for ya? Eg less timing, diff avcs switchover point...?

[Robbks]

Unsure.
my RomRaider ECU Def's don't show AVCS tables.
But he'd posted the info on the changes he makes around here previously.
the 07-08 models had slightly different AVCS mapping to try and fix the issue too.