Testing Knock Sensor
Thread Starter
Pro
Joined: Jun 2001
Posts: 509
Likes: 5
From: Edmonds WA
Testing Knock Sensor
I'm hearing pinging and even knocking sometimes under hard acceleration. A mechanic friend said to make sure the knock sensor was working properly. He said the only way to test it was to have someone watch the timing, while tapping on the block, near the sensor. If the timing was retarded while knocking on the block, then the sesnsor was working. I tried this test and the timing didn't move at all. But, before I go to the trouble of replacing the knock sensor, I wanted to see if anyone else has experienced problems with a knock sensor and if they know of any other way to determine if it is working properly.
If it comes to replacing the sensor... any sage advice on that task?
Thanks!
If it comes to replacing the sensor... any sage advice on that task?
Thanks!
Drifting
Joined: Mar 2000
Posts: 1,630
Likes: 1
From: Woodstock GA
Re: Testing Knock Sensor (K87ZZ4)
Did you bring the idle up to about 1,500 rpms(if you have a scan tool you can do this at idle and see if it picks up and knocks but it has to be above 900 rpms before it can retard timing) when you did this test? If not redo it this is one of the best ways to see if it could work, if it doesn't retard while doing this you are going to have to do some checking first thing I would do is check the resistance from the terminal od the knock sensor to the block then go to the EST module and measure the resistance between terminal D and E it should be real close to what you had at the sensor if not you will have to check the wiring going from the sensor to the module. Check it out and let us know what you find.
David Fulcher
David Fulcher
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Testing Knock Sensor (K87ZZ4)
knock it :jester .... you should be able to tap the block around the sensor with a small hammer or wrench I would think. As to how to it's working correctly vs. at all, I'm not sure.
[Modified by Glock'94, 5:23 PM 2/18/2002]
[Modified by Glock'94, 5:23 PM 2/18/2002]
Melting Slicks
Joined: Oct 2000
Posts: 2,156
Likes: 3
From: La Mesa CA
Re: Testing Knock Sensor (K87ZZ4)
If you need to replace the sensor it is easy, Make sure the eng is cold when you do it. 22mm socket should remove it. Disconnect battery,remove shield,wiring harness,and sensor, you will get some coolent coming out but
not much. Make sure you do not apply sealant to the threads, it will affect
the sensors ability to detect detonation. Comes from the factory with sealant on it. Torque to 14lb.ft.
:cheers:
not much. Make sure you do not apply sealant to the threads, it will affect
the sensors ability to detect detonation. Comes from the factory with sealant on it. Torque to 14lb.ft.
:cheers:
