Unexplained knock retard.

[Cerwin Vega Fan]

I have done two WOT runs where the scanmaster has recorded a knock retard of 10 and 12 degrees. Other times whenever I take off from a stop the scanmaster starts to read a knock retard under very light throttle conditions and it goes up as I give the car more throttle (0.1 to about 1.8 degrees of retard). The odd thing is that some days the scanmaster will record 0 knock retard even under WOT. At first I thought it may be because the engine might be running to cold (160 T-Stat) but I know for a fact when the scanmaster recorded the 10 degrees of retard at WOT my LT1 was at operating temps. Any input on the subject would be appreciated.

Thanks

[grandkodiak]

Sometimes other things can set off the knock sensor such as a new timing chain, roller rockers/cam, even the exhuast has been known to set it off! Have any of these things been changed recently? What kind of fuel are you running?

[LS1ROC]

i have heard of this problem and I believe that if all things are right and i mean you have the correct gas in it and that any headers you may have installed are not rubbing the car and you have it full of antifreeze ( by that i mean any air bubbles could cause detenation by hot spots),,,,,,it could be that you need the lt4 knock sensor. I believe the lt1 knock sensor is a little too sensative. If everything is in good condition and there is no reason for the car to knock...your best bet is to go with the lt4 knock sensor. a lot of lt1 PHANTOM KNOCKS have been fixed ths way. And oh yeah make sure all the engine mounts and tranny mount is good.