BrianB

Was at the drag strip today and noticed that when my car got up into the high rpm range, it sounded like I had pebbles in the motor. Could this be a result of a bent pushrod or bad rockers? Anyway I think it is bad enough that the motor is falling flat on it's face when the noise starts. This is 99 LS1 motor with about 54k on it. The motor is well maintained but this has me concerned. I don't know where to start. It has fresh plugs, fresh oil change, sea foamed the top end, crankcase oil before change, and fuel. Just want to know if this could be the result of a bent pushrod, or loose rockers????

02Reaper

iTrader: (2)

Detonation.

BLKWS.6

+1 for detonation. and thats the knock sensor killing yer power. SOmething is not right.

orangeapeel

iTrader: (18)

You throwin' codes on top of this?

BriancWS6

iTrader: (18)

Yep, your getting pre-ignition. What octane fuel are you running? Have you had the car tuned? What's your timing set to?

slow trap

iTrader: (22)

loose rockers you will valvetrain noise all the time.you are spark knocking and the computer is pulling timing as already stated.maybe try some octane booster .

GuitsBoy

iTrader: (4)

I know you guys think its detonation or pre-ignition, but Im gonna have to disagree and say it might simply be pinging ...

BriancWS6

iTrader: (18)

Cam72aro

iTrader: (28)

I am pretty sure that these are the same thing, pinging is just the slang term for detonation. It all occurs when the fuel is ignited before the spark plug fires. Either way, its the same thing.

BriancWS6

iTrader: (18)

Your very correct, me and GuitsBoy were just having some fun

Cam72aro

iTrader: (28)

somtimes its hard to pick up on the humor generated by a keyboard, lol. I figured it, but wasnt sure. This was my one chance to shine and look important, guess i will have to do it another day, lol.

GuitsBoy

iTrader: (4)

The "jest" smiley could have clued you in

Next time ill use the ROFLamethrower

Rescue Ranger

iTrader: (10)

lmfao

calongo_SS

iTrader: (7)

No, detonation and pinging are the same, and they are after the spark (piston traveling down). Preignition is different, it that's what was happening the motor would already be toast, b/c the force of igintion pushing down against a pistion traveing upwards = boom.

bigredexpress99

iTrader: (15)

damn.....he beat me to it. I saw this thread at work but couldnt post.........bah.

ringram

Yep, detonation is uncontrollable combustion as opposed to a controlled combustion. Caused by unstable fuel charge maybe too lean etc.
Preignition as discussed caused by local hotspots usually, which means it diesels combusting prior to the official spark release.

MagiC5

what kind of transmission?

ls2 bait

iTrader: (11)

my car did that as well. everytime i got on it. it was faint but it was there. on the stock tune the car was running lean in the upper rpms. i actually had to tune my car with very minimul mods because of that.