Knock Sensor...possibly?
02-27-2005, 08:40 PM
#1
Senior Member
Thread Starter
Join Date: Jul 2003
Posts: 1,003
Knock Sensor...possibly?
Well, I'm not 100% sure what the difference in the feel of driving is between a good and bad knock sensor but I've always had a speculation about it. Someone told me to unplug the knock sensor temporarily and drive the car to see if theres any difference. So I unplugged the sensor and went for a ride and the car felt almost exactly the same. I checked for the ghost code before I unplugged it and confirmed there we no codes. And I checked it after I unplugged it and it indeed tripped the code. My only concern is that the knock sensor didn't affect the drive feel when it was unplugged. Should there have been a difference in the driving? Thanks
02-27-2005, 08:54 PM
#4
Originally Posted by PoePoe2797
I checked for the ghost code before I unplugged it and confirmed there we no codes. And I checked it after I unplugged it and it indeed tripped the code.
02-27-2005, 09:19 PM
#6
Senior Member
Join Date: Dec 2004
Posts: 494
theres these crazy things toward the top of the page that are stickied.. read'm 
Originally Posted by kevlo911
How to test knock sensor - The KS may be checked with an ohmmeter.
1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.
2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.
3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.
1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.
2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.
3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.
02-27-2005, 09:49 PM
#7
Originally Posted by PoePoe2797
Your completely missing my question....just because the ecu doesn't have the code doesn't mean its guarenteed to be good....
02-28-2005, 05:02 AM
#8
Senior Member
Thread Starter
Join Date: Jul 2003
Posts: 1,003
I DON'T HAVE AN OHMMETER....jesus christ, why don't people just answer my question. No I dont trust my ECU, it's technology from 95....it's not perfect. Just like how all these people have problems with MAF's and no code ever pops up.
02-28-2005, 05:12 AM
#9
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
Originally Posted by PoePoe2797
Should there have been a difference in the driving? Thanks
02-28-2005, 05:32 AM
#10
Senior Member
Thread Starter
Join Date: Jul 2003
Posts: 1,003
Originally Posted by njmaxseltd
A bad KS will most likely rob your of a few HP. Probably not enough for the average person to ever feel. A dyno run would probably be the best place to see the differance between a good and bad KS.
02-28-2005, 07:31 AM
#11
Originally Posted by PoePoe2797
THANK YOU....finally someone knowledgable enters....
Yeah, and his answer was common sense.
If you ecu isn't throwing a code, it is most likely fine, and the only way to check is on a dyno, or with a multimeter. And don't even go spouting off crap about not having one, you have no reason not to. $20 at radioshack will get you a pretty good one. If you are looking to replace your KS, you are looking for around $90 if you do it yourself, but you seem like the person who would pay a dealership to do it, so enjoy dropping the $300+ instead of just buying a $20 multimeter.
EDIT: http://www.radioshack.com/product.as...%5Fid=22%2D820
and sorry, it is actually $25, but it is auto-ranging (meaning even you can use it.)
02-28-2005, 09:28 AM
#13
Checking the resistance is by far the quickest/easiest way to diagnose if the KS is causing a problem... Go to your local radio shack and pick a VO meter for ~$20 and follow the instuctions listed above and you will know for sure that the KS is bad. If you choose to go the dyno route which is not only expensive you will know nothing more than you did before except that you have made this much power at this time (compared to a baseline run which is sounds like you have not done)... This will in no way determine the exact cause of any loss in power you may experience. Even if you had done a baseline run this will only tell you that you have or have not had a loss in power. You would still have to go through the normal diagnosis procedure to find the exact cause or any such loss...
Now I agree that some people on this board have the tendency to be short and rude with common questions which I personally think is lame as we were all once a newbie, but the fact is that the response about testing the KS properly is the best solution to the question your asking... If the KS is within spec than you would have to go onto testing another part which could cause this type of loss...
Now I agree that some people on this board have the tendency to be short and rude with common questions which I personally think is lame as we were all once a newbie, but the fact is that the response about testing the KS properly is the best solution to the question your asking... If the KS is within spec than you would have to go onto testing another part which could cause this type of loss...
02-28-2005, 09:47 AM
#15
Senior Member
Join Date: Dec 2004
Posts: 494
next time include something like that before you go and blow up on me.. we are not psychic. Buying a ohmmeter would be cheaper than a dyno run... and you don't trust your ecu? 
Originally Posted by PoePoe2797
I DON'T HAVE AN OHMMETER....jesus christ, why don't people just answer my question. No I dont trust my ECU, it's technology from 95....it's not perfect. Just like how all these people have problems with MAF's and no code ever pops up.
02-28-2005, 12:34 PM
#17
quick couple of questions, i hand tightened my KS how important is it to tighten it accordingly like with a torque wrench or something? Also, even if I'm getting the right readings, could it be that my harness is bad? I know its not in perfect condition, where do you get that harness?
02-28-2005, 12:57 PM
#18
Senior Member
Join Date: Jul 2003
Posts: 686
You don't need a torque wrench..make sure it's on tight..Don't worry about the KS
harness just yet...wait till you tighten it again...If you still need the harness you can go to your local nissan dealership or order it online :
www.jerryromenissan.com
part #2407931u01
cost $17.56
harness just yet...wait till you tighten it again...If you still need the harness you can go to your local nissan dealership or order it online :
www.jerryromenissan.com
part #2407931u01
cost $17.56
Thread
Thread Starter
Forum
Replies
Last Post
DC_Juggernaut
7th Generation Maxima (2009-2015)
4
09-28-2015 04:07 PM
ballerchris510
5th Generation Maxima (2000-2003)
6
09-11-2015 05:29 PM