I have a bmw 545i and i cant find the knock sensor i think they are under the intake manifold is that right

What engine ? 4.6 or 5.4 l Factory repair manual only show's one , under the intake manifold .
Knock Sensor (KS) - 4.6L and 5.4L Removal

1. Remove the intake manifold. For additional information, refer to Section 303-01B .

1. Remove the knock sensor (KS).
   1. Disconnect the electrical connector.
   1. Remove the nut and the KS.

should be under the rear seat on the right hand side. happy new year

2003 kia rio, It is located under the intake manifold. Get underneath the car, pull the oil filter...it is right above it and in clear view with the oil filter out of the way. The connector plug is up top behing the air breather on the firewall.

Under the intake manifold. Make sure you get the harness for the knock sensors. and clean out all of the rust and junk you're going to find donw in the holes before and after you replace the sensors.

It's located deep in the valley! Under the "LOWER intake manifold". copy and paste this link in your browser, or try clicking on it. It may be helpful to you.

http://x.nissanhelp.com/forums/pathfinder/7890-3-3l-knock-sensor-relocation.html

I didn't find this link until after I had already disassembled my truck. This is the hardest job that I've taken on thus far, hope I can put it all back together properly. I changed the gaskets on the valve covers since I had everything off.
To answer your question: It's under your lower intake manifold, so it's a hard job!

They are Located UNDER Intake Manifold !! #1 bank in Front #2 Back.

1. Remove the intake manifold.
2. Gently pry up the rubber covers.
3. Disconnect the knock sensor electrical connectors.
   1. Remove the knock sensors.
   INSTALLATION PROCEDURE
   
   NOTE: Refer to Fastener Notice in Service PrecautionsInstall the knock sensors. Tighten Tighten the sensor to 20 N.m (15 lb ft)
   
   1. Connect the knock sensor electrical connectors.
   2. Push down on the rubber covers.
   3. Install the intake manifold.
   
   

i have toyota windom 4vz-fe i need locate knock sensor

The knock sensor is located under the intake manifold.The best way to get to it is to lift the car completly up go undert it and look right under the intake manifold.There is a steel tube about 2inches thick that will be blocking your view but its right behind it.GOOD LUCK.

You need to pull off the entire intake manifold/plenum assembly. The knock sensor is bolted to the inside of the cylinder block, it is in the middle of the culinder block.

The knock Sensors are located under the Intake Manifold at the top of your engine. The top will have to be taken off along with the intake manifold. Knock Sensors in past silverados used to have a problem with leaking water that corroded the sensors from washing the engine. Most times when you go to replace the knock sensor you will have to replace both along with the wiring harness that includes the the gaskets the knock sensors are surrounded by. After that you have to check the resistance to make sure you dont have any problems and then reinstall all parts along with a new intake manifold gasket. A good mechanic can do this for you in a day and charge you around $400. If you try to go to some place like a chevy dealer you will pay over $800. This is from experience of just replacing mine 2 weeks ago.