if I unbolt the sensor from the block and clear the code it is fine.

I bolt it down and torque to 14ft/lb and BAM! restricted performance.

Car seems to be running smooth, no detinations audible

 

I replaced both of my knock sensors for false readings. If you want to check it swap the plugs and see if your code is on the same bank.

 

tried that with the same result. doesn't seem like a typical ecu fault, since it doesn't send it if it is not bolted down.

 

btw- it is a p0332 knock sensor low input bank 2. no other codes.
1998 xj8 120k

 

Did it change from #2 to #1?

 

sorry-I read you wrong...I swapped sensors side to side expecting the code to move to bank 1..it stayed on 2...i will swap the plugs..thanks

 

so I swapped the plugs and the error moved to bank one?? If I swap sensors the error stays on bank 2. So whichever sensor I mount to bank 2 on whichever plug I go into throws the code.
What could cause low input from the mounting point?
I have tried three sensors in that position now, all throw the code right away.

 

Swapping the plugs moved the problem from one bank to the other is a good indication that the sensor or another problem exists on that side. Wiring up to the sensor could be ruled out. If you haven’t already I would recommend replacing the sensor.

 

Since the sensor does not set a code when it is not fastened to the block, a zero-cost experiment would be to bolt it down in its original place with LESS TORQUE. Say, 10 ft-lb instead of 14. I remember reading somewhere, maybe on this forum sometime back, that the output of the piezoelectric stack (which is how these work) depends on the compression with which it is mounted.

Anyway, won't cost anything to check and might provide some food for thought for the rest of us.

 

thanks, will try that, also ordered a brand new sensor, I have tried three but they were used. I try to keep them in a safe place, but maybe all three got beat around and ruined