I bought a very clean 1991 4runner 3vze and had the valve job done week 2. Had oem knock sensor, oem pigtail, a very reputable shop doing the work and now still have the lamp on. Shop states they would have to trace down wire??? I asked why not replace bad wire (only one) with a new shielded wire from ecu to knock sensor pigtail harness. Any thoughts alot of people talk about external mounting of KS - I don't want to do that. How difficult is it to run a wire to sensor correctly?

 

There is a lot about knock sensor issues on this site, I suggest you read them. Another thread on it isn't needed. If your having trouble finding them try using key words in the search section. I solved my code 52 issues with the help from these guys. Kick up your feet and read as much of it as possible. GOOD LUCK!

 

I am looking for the AC volatage out put of a correct Knock sensor any one have the range?

 

To get at the sensor harness at all, you pretty much have to remove the intake plenum at a minimum. You MIGHT be able to get in deep enough with just the throttle body off to reach the truck-side of the harness, but I can't say for sure, I'm just trying to visualize from memory. If you want to run wire all the way to the sensor and not just to the plug at the end of the pigtail, you're going to have to pull your plenum and intake manifold, which means a bundle of vacuum lines, a couple coolant lines, a handful of gaskets. Not wildly difficult to do, but kind of tedious and annoying.

Either way, if they want to replace it or trace it, the labor on it is going to be pretty much identical, they may just save you a little cash for labor/parts. As Trent said, I'd read up on the problem threads that exist. KS are a somewhat common problem with at least a few potential solutions. You may find an easier answer to your problem than replacing the wiring.

 

Just a thought... I worked on a 91 runner that had a very similar issue with that code never going away. It had a pcm from a 93. Those years have different part numbers for knock sensors (from Toyota they are different). Make sure the knock sensor that got installed is for the year of your pcm and not the truck itself, unless it's the stock pcm then that's probably not your issue. But for the rig I worked on, the newer ks (matched to the newer pcm) ended up fixing the cel.