Michael02hawk

iTrader: (26)

The noise I'm concered about sounds something like a metallic buzz, rattle or crackle. I wouldnt call it a knock, or slap.

The car is an M6, forged internals with 2k miles.
I've always used 93 octange gas...Mobile, or Hess.
The engine was Dyno Tuned, with LS1 edit 4 weeks ago.

Two weeks ago, I just started hearing the above noise, only when I started to accelerate from a stand still.

Last week, I've noticed the noise when i'm giving the car some gas...I'm not talking about getting on it or anything, just a little push of the gas pedel and i'd hear the descibed buzz.

And now this week, I'm noticing that metallic sound more often, during normal driving, cruise control, etc.

So, what-ever is going on, it seems to be slowly getting worse.

I'm not sure, is the engine pinging? any other thoughts or ideas?

Thanks!

99BLACKBIRD

iTrader: (1)

Where's the noise coming from? Engine bay or rear end?

Michael02hawk

iTrader: (26)

From the front of the car, the engine bay, I'm pretty sure.

Also, now that I'm thinking about it, I also just installed two 18mm plugs, into the rear 02 sensor holes, removing the stock rear 02's altogether.

I used anti-seize, but could I be hearing an exhuast leak making the sound I described?

99BLACKBIRD

iTrader: (1)

Does the noise get louder with revs, or is it at a constant level?

Michael02hawk

iTrader: (26)

The noise goes away with anything more than a touch of the gas pedel.

BigSteele

iTrader: (17)

could be the rear end gears, my started doing that on deceleration and got worse with time. It could either happen on accel. or decel.
I thought it was my transmission at first but everyone told me it was probably the rear end.
Mine would go away if I put it in neutral or if i barely got no the gas, only made the noise when it was "engine braking" to any degree

try searching the gears/axle section and see if you have the same exact symptoms

99BLACKBIRD

iTrader: (1)

check you pullies and idler tensioners.

Michael02hawk

iTrader: (26)

I'm pretty sure its not in the back end...actually my noise is the reverse of what you desribed. I only hear it at 'light throttle', reguarless of the speed.

I dumped a container of octane boost in todoay, and filled it up,
but only to have the same results.

I like the idea on the pullies and tensioners.
I'll get on that tomorrow night, along with pulling out the rear 02 plugs, and putting the stock sensors back in.

any other thoughts?

WS6FirebirdTA00

iTrader: (33)

could be spark knock. might have too much timing at part throttle, guess its called burst knock, not sure ive never had it. anyway to scan for KR? could have a plug fouled out, thats a hard noise to diagnose over the internet lol

Michael02hawk

iTrader: (26)

I've found this post at LS1-Edit, that seems to describe what I'm talking about. The 2nd paragrah mentions the "inital throttle tap" condition.

But it doesnt have any follow ups.

http://www.ls1edit.com/pipermail/ls1...07/005726.html

WS6FirebirdTA00

iTrader: (33)

if its burst knock its in the tune, call the tuner back and tell them about your issues

GregWS6&z28

iTrader: (8)

i had/have the same buzzing noise that you are describing. I pulled my valve covers to find a worn out retainer and smashed valve locks. the rocker arm had dug down into the retainer and smashed my valve locks into 5 pieces. I was very close to dropping the valve, but the metallic noise was sooner than when i decided to pull my valve covers
here's a pic of what it looked like

it's the backmost valve, and my valve had dropped some

GregWS6&z28

iTrader: (8)

find out anything?

Michael02hawk

iTrader: (26)

I havnt find anything out yet....I believe the noise was less today. Possibly becuase I've gotten about 125 miles on it since I added the octane boost? Its hard to say for sure.

Man, sorry to hear about your valve locks and all, I'm certainly hoping I dont have a simular problem!

One more note I should add, this metallic sound I'm talking about, only exists under load. So if the car is sitting idle, and I go with a 'little throttle' I dont hear it. If I'm in motion, and add a 'little throttle' it'll most likely be noticable.

Is anyone familiar with the Bust Knock sections, within LS1-Edit?

I'd like to back the timing off a degree or 2, but I'm not familiar with the Delta Air Flow, Tip in Max, and Degree boxes.

WS6FirebirdTA00

iTrader: (33)

just go through the timing tables and pull 2-4 deg everywhere and see if that will make it go away. i have never messed with burst knock but from what you say it sounds a lot like its knocking. check all your plug wires and make sure they are clicked in and when was the last time u changed plugs?

Michael02hawk

iTrader: (26)

Which section is the timing tables?
I assume the degrees section under 'Burst Knock'?
So I should drop the number, in each RMP box, down 2-4 degrees?

Does that sound like I'm on the right track?

The plugs are brand spanking new. But the wires on the other hand could be a problem...The engine was worked on twice over the past year, so the stock spark plug wires have been handled quite a bit - is it possible one or more of these wires could contribute to this???

btw, thanks a million for your on-going suggestions!

WS6FirebirdTA00

iTrader: (33)

pull the wires and inspect them, make sure they arent burnt, if they arent put them back on and make sure they click one time on the spark plug side adn 2 on the coil side. one might not be getting a good connection. i dont ahve ls1 edit so i hope someone can chime in, ill try and look in hp tuners later and see if i can come up with something maybe u can relate to. i was takling about maybe pulling timing from the high and low octane tables, and then see if that works for you, then u know thats where you problem is and u can work on burst knock. cuase thats the only why i know how to tell u what to do lol ill try and look thouhg

Michael02hawk

iTrader: (26)

Ok guys,

The knock or pinging is slowly getting worse.

Is something degrading here on me, or is this a problem with the tune?

WS6FirebirdTA00

iTrader: (33)

have you checked all the plugs and wires to make sure they were ok? how is the air/fuel ratio at part throttle?? do u know??

WS6FirebirdTA00

iTrader: (33)

in hp tuners the burst knock has a table for delta air, if u have this try to incrase these numbers slightly. are you getting any kr, i forgot if u had a scanner or not