When ever i start my car it clatters pretty bad until oil pressure builds up . But no Knock retard registers on the scanmaster . Once the oil pressure builds it quiets down quite a bit but the whole clattering thing just started
the other day . Any suggestions or help is greatly appreciated . Thanks

 

I just did the hose test (where you take a piece of hose and put it up to your ear and move it along the valve covers , manifolds , etc .) and i heard nothing out of the norm. when it was warm . But it clatters really bad on a cold start then goes away when oil pressure builds and when the car is already warm it barely clatters when oil pressure builds then goes away . No Knock retard registers at all on the scanmaster even on startup when it does clatter . HELP ? Thanks .

 

This seems to be a fairly common occurance in the LT1 cars. With mileage comes noise. The rocker arms and lifters get pretty noisy. Nothing to worry about too hard as long as yo continue to get no knock retard. If it was a ignition problem I am sure you'd register some retard on the scanner. I myself was unable to cure this until I replaced the rockers and lifters when I did my cam change. Like I said though there is no real cure for it and is not out of the norm.

 

The knock sensor is "tuned" to the frequencies that represent pre-ignition and doetonation. The knock module further filters the noise. A rattle from worn lifters, piston slap, bearing knock, etc will **not necessarily** cause a noise of the correct signature to reach the PCM's knock retard logic.

 

Very technical there. LOL LT1s are notorious for valve train noise and piston slap. I'd chalk that noise up to a wearing motor.