grey-goat05

iTrader: (1)

I have tried just about everything to narrow down what this sound is on my 05 A4 vette. I've just about given up. Its a much more metallic sound in person. It happens under moderate acceleration in the 2 - 3k RPM range.

http://www.youtube.com/watch?v=5E-1wCRVgjM


Here's what I've tried...

Detonation - put in a brand new set of plugs and drove it around for a while - no signs of detonation on the plugs and nothing in HP tuners when the noise is happening.

Exhaust leak - I have kooks, high flow cats and 08 NPP mufflers - I swapped back to the stock exhaust, and changed header gaskets - didn't make a difference.

Anything bouncing around near the fans or pulleys - gone over this a dozen times - everything is tied back no where near being able to hit the fans or pulleys.

I put it on a dyno last week - it would not make the sound - even applied the brakes on the drum to put more load on the car... still nothing.

I regreased my caliper pins and tightened up my brake pad clips - didn't make a difference.

Pulled and looked over the valve springs, rocker arms etc...

The noise does seem to stop when I apply the brakes so the last few days I've been concentrating on them - but can't see anything wrong.

I'm not sure what else to do. My mods are listed below - I put them all on last November - it started making this noise a few months ago.

cam
3200 stall
kooks, high flow cats, NPP mufflers
DTE rear end with 3.42 gears

Anybody got any ideas?

mattinokc

man I wanna say transmission pump but I might be wrong

I have heard detonation like that when i was working with a tuner on a old car of mine

sounded very similar but higher up in rpms

not sure

hope you find it man

c6 batmobile

iTrader: (2)

What about an exhaust clamp hitting the frame underneath?

You said HP tuners was showing no KR?

Does it only happen when you apply the brakes or is it under mild acceleration?

65panel5.3

once had a lifter that ticked but only under load like that altough if it stops when hitting the brakes its doubtful it would be that.. its tricky. maybe a longer vid with more of whe the sound comes and goes would be helpful ive also heard wheel bearings click like that too

grey-goat05

iTrader: (1)

I've checked all the exhaust clamps, there clear of everything.

The sound only happens on acceleration - so thats why I put it on a dyno last week to try and pinpoint the noise - however it didn't make the noise on the dyno - this I think has stumped me the most...

The noise does seems to go away when I apply the brakes as I'm accelerating.

HP Tuners shows no KR when its making the noise.

I took a couple video's today - its hard to make it out on most over the road noise in the camera - but this one is a little longer:

http://www.youtube.com/watch?v=5jQxTp71o_8

c6 batmobile

iTrader: (2)

coming from front or back? can you tell?

grey-goat05

iTrader: (1)

Sounds like its coming from the front of the car. I think from the passenger side - but not sure on that.

Also forgot to mention it does not make the noise if i put it in neutral and rev it up.

Schwanke Engines

iTrader: (1)

It sure sounds like part throttle pre-ignition to me. What kind of timing are you running when it is doing it?
Can you post a log file?

grey-goat05

iTrader: (1)

It does sound very much like Detonation. However even if I soften up the tune it makes no difference. Thats also why I swapped in new plugs and checked them - no sign of detonation on the plugs.

And I figured if its knocking like that on the street - it should on the dyno as well.

Greekey

iTrader: (3)

I had a similar sounding noise happening when I was accelerating. It turned out that it was a blown exhaust manifold gasket. Double check and see if you have any carbon build up around the exhaust manifolds where they bolt to the engine. You have to look very closely. It will be extremely difficult in some cases to spot an exhaust leak coming from the gaskets.