92 pathy knock sensor

[Jhurkmans]

Hey, so i recently got an error code on my 1992 nissan pathfinder xe v6 3.0L. Can anyone shed some light on where the knock sensor is?

[Slartibartfast]

Under the intake manifold, unfortunately. The '90 service manual (which you can get here, I don't have a link to a specific '92 manual unfortunately) should get you started. Looks like EF&EC 114 and 155 both have test procedures for the wiring harness, and EM shows how the intake fits together if you do end up having to dig out the sensor. (The '95 manual also suggests loosening and re-tightening the ground point for the knock sensor harness.) You'll need new upper and lower manifold gaskets, and this would not be a bad time to do your valve cover gaskets too if you haven't. When I had mine apart, I also cleaned the crap (literally) out of the spark plug wells and replaced the plugs, because they'll never be easier to access than they are with the intake off.

 

Before I put mine back together, I relocated the sensor to the back of one of the heads. I don't know that it'll do its job as well from there, but its job is limited on these rigs, and I did not want to take the whole intake apart again if the sensor died.

[onespiritbrain]

8 hours ago, Slartibartfast said:

Before I put mine back together, I relocated the sensor to the back of one of the heads. I don't know that it'll do its job as well from there, but its job is limited on these rigs, and I did not want to take the whole intake apart again if the sensor died.

I read that its only function is throw a code and doesnt cause the ECM to adjust fuel maps. 

[Jhurkmans]

So luckily my neighbor has a 95 nissan chevy and he gave me a repair manual for it. It spans '87 to '95 pathfinders and nissan trucks. I found the sensor. Pulled off the upper intake manifold and just spent afew hours cussing up a storm and forcing my hand deep into the engine to unplug the last knock sensor. I relocated it to the top of the intake manifold but i feel i will change that soon. I put everything back together and quadruple checked everything over and over again. Started it up. After a few tries of it getting started up and running again, the idle seems fine. But now when i put it in gear, the while vehicle shakes fairly violently and the moment i put it in park, the vehicle shut itself off. Any thoughts? 

[Slartibartfast]

Sounds like you have a vacuum leak. I had a similar problem after taking mine apart, because Rockauto sold me the stamped-steel intake gaskets meant for a VG33 instead of the thicker steel-and-rubber gaskets meant for the VG30. Surprise, they didn't seal, and it shook like hell in gear. Also make sure you got the PCV, brake booster, all of that hooked back up correctly.

 

And yeah, I'm pretty sure the computers on these just set a check light and retard the timing for safety if the knock sensor reports that the engine's making bad noises. Not like newer rigs that use the knock sensor as feedback for their tuning. I was reading the other day about some new cars measuring the resistance of the spark plug gaps between sparks to monitor combustion as it happens. Crazy stuff. Makes the WD21 computer look like stone knives and bear claws.