Howdy...this is my first time digging into my 3.0 3VZE motor. I've lost power and found one dead cylinder with ZERO Compression...so I am pulling the Heads to take a look see. After pulling the Intake manifold I found what is called the "Knock Sensor." The top of the sensor where the two wires exit the unit appears to be allowing oil to leak out of the sensor and pool into the open area under the Intake Manifold, which may allow the contamated oil to enter back into the engine block...??? (I don't know...I'm just guessing???)

My questions is: what does the "Knock Sensor DO" and may I remove it and plug off the hole leading into the Block without cause myself new problems...???

The two wires coming out of the Knock Sensor come up from under the Air Intake Chamber area and enter the wire harness on top of the Air Intake Chamber then disappear into the mass of wires leading back to the battery/fuse/electrial/control area.
Many Thanks...Rex M.
I'm working on my 1991 4Runner with 284,500 miles in STOCK Form...which is going to be changing soon...))
Later On and HAPPY TRAILS TO ALL...!!!!

 

Just like the name implies the knock sensor senses engine knock, or preignition. It then tells the engine computer to retard the timing a bit until the engine stops knocking. I don't what'll happen if you remove it completely. If you're going to leave it in there definitely replace the wiring, it's a common trouble spot on the 3.0.

 

Why remove it? Just replace it. If you're going to do a job, do it right the first time. If you're worried about the price of a new sensor (approx $150 at Dallas Toyota), then see if you can find a used one at a nearby junkyard. I would think that unless you do something to "fool" your ecm, you'll end up with an engine that may not run very well. Pre-detonation is not good for engine longevity, and it will rob some power from an already under-powered engine. Also, you'd probably end up with a CEL for code 52 when your ECM noticed that the knock signal is missing.

 

I was expecting an answer along these lines...just wanted to make sure.
While I have the heads off should I go over-size on the Valves then do the Headers?
I'm basically building this rig for my new step son to grow into, he just turned 14.
Thanks Big Time...for taking the time to reply.

I also have 1995 4Runner I'm selling now.
Heres the link to the 1995 4Runner I have listed on Craigslist:
http://reno.craigslist.org/cto/1094621181.html
After selling this one I hope to find a good 3.4L 4Runner to fix up.