Diagnostic Aids
WARNING: This page is about a different car, the 1992 Pontiac Grand Prix, 1992 Oldsmobile Cutlass Supreme, and 1992 Chevrolet Lumina. However, it is still accessible from the selected car via links, so may be relevant.
Check knock sensor signal circuit for a potential open or short to ground. An open knock signal circuit would cause 5-volt reference to remain high at ECM knock signal terminal. A short to ground in knock signal circuit would cause 5-volt reference signal to pull low to near zero volts. Resistance to ground through knock sensor should be 3300-4500 ohms. Also check for proper installation of MEM-CAL.