knock sensors! someone help please!
08-11-2010, 04:58 PM
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knock sensors! someone help please!
2001 chevy 2500HD with the 6.0L and 5-speed. had a code for both knock sensors, so i replaced them. the 2nd sensor was all corroded and nasty which was to be expected... so anyway, cleaned the holes out, replaced sensors, put everything back together and about 3 drive cycles later the light came back on for both knock sensors. i did some more research and found out sometimes the knock sensor harness can be bad so i went to the dealership and bought a new harness... took everything back apart and replaced the harness. again, 3 or 4 drive cylces later the light popped back on for bank 1 and bank 2 knock sensor low voltage. and bank 1/ bank 2 knock sensors pending (whatever that means).... some have said give it time and let it dry out in there... i have had the code cleared 3 times in the 2 months since ive replaced these parts and its always like 3 or 4 drive cycles later the light pops back on. its ratarding my timing, killing my upper range power/gas mileage, and i cant put this supercharger on untill i fix this problem!! someone help! thanks.
08-11-2010, 05:24 PM
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i believe so... i couldnt tell you what that number is, but i remember having the torque wrench out and torquing them down after reading on gmfullsize. im fixing to tear it all back down here in a few minutes for the 3rd time. even if they werent torqued down to the factory specs, i dont see how that would create a problem. they just sit there and detect excess knock/engine movement... ive seen plenty of people repace these and just tighten them down with a wrench and never had a problem out of them. what would cause them to have "low voltage"? i dont see how water could have gotten back in there, i siliconed the rubber plugs good. i dont think i got bad sensors from the part store, you would think maybe one might be bad, but both are showing up on the codes
08-11-2010, 05:56 PM
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i believe so... i couldnt tell you what that number is, but i remember having the torque wrench out and torquing them down after reading on gmfullsize. im fixing to tear it all back down here in a few minutes for the 3rd time. even if they werent torqued down to the factory specs, i dont see how that would create a problem. they just sit there and detect excess knock/engine movement... ive seen plenty of people repace these and just tighten them down with a wrench and never had a problem out of them. what would cause them to have "low voltage"? i dont see how water could have gotten back in there, i siliconed the rubber plugs good. i dont think i got bad sensors from the part store, you would think maybe one might be bad, but both are showing up on the codes
08-11-2010, 07:04 PM
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now i got bigger problems. the back sensor wont come out... it just spins and wont unscrew... cheap @$$ parts! what now? am i going to have to replace the whole valley cover or what?
... at first just the top was spinning inside the sensor... so i took a hammer and screw driver and gently tapped grooves in 4 spots around the sensor so the top would grab the sensor itself an turn it. it worked, but now it still wont come out... entire sensor turns, and you can even wiggle whole sensor side to side in the hole like its just sitting there not screwed in... but it will not come out? grabbing the hex part i can pull on it and it wont budge, but it will spin the whole sensor freely.
... at first just the top was spinning inside the sensor... so i took a hammer and screw driver and gently tapped grooves in 4 spots around the sensor so the top would grab the sensor itself an turn it. it worked, but now it still wont come out... entire sensor turns, and you can even wiggle whole sensor side to side in the hole like its just sitting there not screwed in... but it will not come out? grabbing the hex part i can pull on it and it wont budge, but it will spin the whole sensor freely.
Last edited by bighoss77; 08-11-2010 at 07:20 PM.
08-11-2010, 07:08 PM
#6
How tight did you screw them on? It's only supposed to be 15 lb/ft, but I think it's unlikely you could have stripped it.
You might want to recheck all the wire connections to make sure their tight.
Also, how was the code cleared? I'd recommend disconnecting the battery for 10-15 seconds and then reconnect it.
You might want to recheck all the wire connections to make sure their tight.
Also, how was the code cleared? I'd recommend disconnecting the battery for 10-15 seconds and then reconnect it.
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08-11-2010, 07:27 PM
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OMG... is there supposed to a be a little hole at the bottom of the rear knock sensor bore? theres a damn hole and oil is filling up in there!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! wtf? and the mf-ing sensor broke off in the threads... im in some **** now. where the hell do i buy a new valley cover??
08-11-2010, 08:16 PM
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please dont tell me they screw into the block!... yeah it was the raggity sensor, it broke and was spinning inside the case, i had to ping it with a screwdriver and hammer for it to grab the case of the sensor so it would spin as one unit like it was supposed to in the first place... it ended up breaking off in the threads though. that back hole was covered in oil becuase there is a hole at the bottom of the "hole" for some reason... i guess i didnt catch it the first time. so do they screw into the block, or into the valley cover?