How do I replace/relocate 1999 QX4 3.3L knock sensor ? Had the vehicle in for a minor repair and the mechanic said I would need a new knock sensor. Had the vehicle back for a week and now it work start. The engine is cranking but no fire. Seems to indicate that knock sensor is bad. Schematic I saw locates knock sensor under manifold. Is there a work around that lets me relocate? Or will I have to remove the manifold?

It's possible to relocate the knock sensor by cutting the wires that lead to the knock sensor (I think somewhere right after the right-hand valve cover - see EC-274 for a wiring diagram and colors) and wiring it to a new knock sensor that you bolt somewhere on top of the intake. It won't work as well since it's more difficult for it to detect knocking. I don't think a failing knock sensor will cause a failed start, though.

Welcome to NICO.

Thanks for the welcome. If the diag code from my mechanic said I had a bad knock sensor, and know it won't start what might prossibly be the problem. I like to do it myself. Knock sensor replacement cost $200 +.

I don't think a failing knock sensor would cause it to fail to start. I'd expect it to just retard the spark a bit and get you home.
There's no reason to immobilize the car. Heck, nothing had knock sensors until the 1980s.


Chuck

Thanks Chuck. Towncivillian thinks the same. I will pass this by my mechanic.

Have the car scanned, the knock sensor wont cause a no start condition.

btw the knock sensor isnt that expensive so 200+ is way to much