5speedz34 Posted April 12, 2011 Report Share Posted April 12, 2011 I bet if you rock the motor forward it might not be all that hard to get at. Quote Link to comment Share on other sites More sharing options...
gp1991 Posted April 12, 2011 Report Share Posted April 12, 2011 yeah i was going to see about changing it when i do my plugs. it shouldnt bee too hard to get at with the motor forward Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted April 12, 2011 Author Report Share Posted April 12, 2011 I just scanned the GP today. It says no knock and 0° of knock retard at idle... when I hit the motor on the lift hook it'll detect the knock. I noticed though, once it warmed it had 15° of knock retard. I'm starting to believe this isnt the sensor based on the fact that it was detecting when I'd smack the motor... I do however have some sort of knock coming from the accessory belt area. Its the loudest right around the water pump... to obviously eliminate the chance that thats setting off the engine code. Is it possible for the water pump to be making a sort of knocking noise. I noticed that when the knocking goes away it makes a grinding type of noise... and when I'm cruising at 45+mph the knock sensor code never gets thrown, it only does it in city driving, which kinda makes me think since its idling higher, the knock isnt being detected by the sensor. Any thoughts? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 12, 2011 Report Share Posted April 12, 2011 the ECM will only register knock and retard timing when above a certain coolant temp. it will show knock counts when under that temp, but does nothing about it. did the knock counts increase at all when the 15* retard kicks in? take a look at your belt tensioner, when it went on the MC, it make a knocking noise when i gave it heavy throttle without allowing the TCC to unlock. damn near cut into the timing cover too(replaced plastic pulley with a steel one). water pump IS possible, you could stick a 3/8" ratchet into the tensioner, remove tension from the belt, move it off to the side and try and spin pulleys by hand. if they make noise from that, it's a clue. Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted April 12, 2011 Author Report Share Posted April 12, 2011 the ECM will only register knock and retard timing when above a certain coolant temp. it will show knock counts when under that temp, but does nothing about it. did the knock counts increase at all when the 15* retard kicks in? take a look at your belt tensioner, when it went on the MC, it make a knocking noise when i gave it heavy throttle without allowing the TCC to unlock. damn near cut into the timing cover too(replaced plastic pulley with a steel one). water pump IS possible, you could stick a 3/8" ratchet into the tensioner, remove tension from the belt, move it off to the side and try and spin pulleys by hand. if they make noise from that, it's a clue. When its at 15° its not detecting knock. I noticed once the CEL came on, only the knock retard changed not the knock detection... however I dont know how sensitive the scanner is because when I'd pound on the lift hook it would only detect ever 3-4th pound. It may be possible its the tensioner thats what was wrong with my 88 only it made a much quiter knock. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 12, 2011 Report Share Posted April 12, 2011 the scanner has nothing to do with sensitivity. the scanner will show exactly what the ECM sees. Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted April 12, 2011 Author Report Share Posted April 12, 2011 the scanner has nothing to do with sensitivity. the scanner will show exactly what the ECM sees. So maybe the sensor hasnt totally failed but its on its way out? Then again I'm not tapping on the motor right by the sensor so it might just not have been detecting all the hits. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 12, 2011 Report Share Posted April 12, 2011 possibility. make sure the connector is working as intended as well, since a loose/flaky connector can cause all kinds of fun. Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted April 12, 2011 Author Report Share Posted April 12, 2011 possibility. make sure the connector is working as intended as well, since a loose/flaky connector can cause all kinds of fun. Do you know where the wire runs, does it go straight to the ECM or does it do a lap around the motor? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 12, 2011 Report Share Posted April 12, 2011 i would think GM would make the distance as short as possible, this is one of those circuits that is VERY sensitive to external interference. Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted April 13, 2011 Report Share Posted April 13, 2011 Just replace the sensor....... Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted April 15, 2011 Author Report Share Posted April 15, 2011 I've "just replaced" a lot of shit on this car to turn out it not being the problem, I just want to be sure this is it... @Rob, today I bought a stethoscope to see if i can pin point where the knocking was coming from... and of course I cant get it to knock now... Even without the knock though the CEL was still coming on. Am I pretty much looking at a new sensor now? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 15, 2011 Report Share Posted April 15, 2011 what was the resistance reading for the knock sensor? Quote Link to comment Share on other sites More sharing options...
ns87 Posted April 15, 2011 Report Share Posted April 15, 2011 on my CS, the sensor got really brittle and the connector broke. If I wedged the wire from the connect into the sensor it was fine, but would occasionally fall out. It gets really hot back there, and is a pain to reconnect, so eventually I cut another connector at a junkyard (that wasnt broken), and butt connected it. It wasn't pretty, but it worked. Quote Link to comment Share on other sites More sharing options...
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