I have been chasing the same problem. Instead of buying a bunch of sensors to get the right one, I might try adjusting the resistance to get it in the right range. Thanks for the video.
Your welcome. That's a great idea! Forgot all about doing that. I use to wire in a potentiometer and adjust it until the car would run more stable when testing sensors. Best of luck!
I have been dealing with this same problem for the last 6 months I the last too I have bought bad have been from the Chevy garage thank you for this videoi am gunna try this
Great info, I will look for 99K ohms. Hope that helps, I have been struggling for 1 year on this as well. Too bad a GM engineer does not address this to the public... Frustrating!!! Thanks
If the issue is only the default sensor resistance, it may be possible to adjust that resistance value with an adjustable dual potentiometer circuit inserted into the knock sensor lead. A pair of 10 turn Bourns 3006 trimpots could be used with a 20K trimpot (Bourns 203) in series with the sensor lead and another 1 M trimpot (Bourns 105) from the computer side of the 20K trimpot to ground. The computer would see a resistance value adjustable to a precise value it accepts as normal, calibrated by watching an ohm meter attached to the computer side at the junction point of those 2 trimmers. The sensor is likely to still function normally to detect any actual engine knock, even though its untriggered resistance is slightly out of range if unadjusted and uncalibrated by a compensation circuit. Trimpots allow adjusting untriggered resistance so the computer is not overly sensitive to the sensor untriggered resistance. When a sensor detects an actual knock the resistance change will be many times greater than any small value change done to calibrate the untriggered resistance. This "gadget" type of circuit could delay or eliminate need for replacing a sensor that otherwise still works fine to detect an actual knock, but is only slightly out of range for the expected resistance seen by an overly sensitive computer that wants a new sensor it does not actually require to continue working, only because the system was designed to avoid any user calibration and sell more new sensors to replace old sensors that would still be in service for years if calibration adjustments were an included feature. Go figure why that would be done that way. Selling expensive repair parts is big business.
@@stuntcountry8488 Knock sensors are actually a piezo transducer type microphone (a crystal microphone) that generates AC output signal level voltage can be read on a meter set for AC millivolt range if the sensor is tapped with a screwdriver handle to simulate a knock. How that is detected and read by the computer I am not sure but simply locating the sensors in an accessible location makes sense and an engine knock should be picked up anywhere on the engine. Putting a predictable replacement sensor underneath an intake plenum isn't exactly a love letter from an engineer, but is sadistic and asinine.
I’m having the same problem on my 2012 jeep. Replaced knock sensors and wiring harness and still comes on. And they all are in the same horrible place. I’ve redone it twice now and can’t figure it out.
Unfortunately I had to find them by trial and error. I ended up buying a total of 8 different knock sensors and swapped them in and out until I found what worked. Based on the testing I did it just happened to be for me the knock sensors that had a measured resistance in the middle of the required range from the Chevy specifications.
my knock send green wire is barely tied no tape nothing ,also other knocksen wire dark blue ? cars been driving about 6 months the way so do I put both together blue and green wires and solder them together fonnectirfor blue had 2 wires but other was cut and taped how would you connect them I'm not getting a code I'm just trying to fix my corroded wires that I found ,? thank you appreciate some true advice Lol I don't want it to get a bigger problem ty
Oh wow surprised you didn't get a code. Ideally you want to soldier or crimp green to green and blue to blue. You could also join them all to one but then it would be only one sensor. My only worry is once you fix it all you might get a code. The old saying if ain't broke don't mess with it. Or you could try it and see but with the caveat it could cause it to code. Really just a choice. Best of luck.
Hi, Your welcome! Yes still going strong with no codes. Still haven't moved them back under the intake manifold yet I am waiting till summer when I have more time.
@@stuntcountry8488 that's great news! It wasn't quite clear how you have them secured against the block for the testing period. Any insight on that would help me set this up. I'm going to bring my multimeter to the parts store and check them before purchasing looking for that middle range.
@@dougshuckra2063 yeah it was an after the fix video so I didn't go into detail. Basically I found two spots that the sensors would thread into. Believe it or not there are several spots on the engine block that the sensors will thread into at the front and back of the block. I just used an old sensor so I didn't damage the new ones and looked for a spots on the back and side of the block where the sensor would thread into. I decided on the spots where I would not have to cut and extend the wire harness thus adding more resistance to the circuit.
I just checked the sensors again on the block. Both are at 100.3k and both throw a small mv reading when I tap on the block. I’m starting to have a hard time believing that these sensors are the issue here. The resistance back to the ecm is the same on both pins in the connector too. I’m at a loss.
thanks well I hope it goes well for me and now thinking back into who did it to my wire's ,I'm in wow it was the smog shop last May 2023 I rem also he disconnected it and left it and it melted on the block ,lydh both are left side in between spark plugs so ,and it's a1994 TBI well her e goes . 🙏 a marie
oh there the easy way there my 94 S10 has them already threaded both on block near spark plugs driver side and passenger also the wires have really been damaged and this time .I'm gonna wrap them w foil to real tight and if it gives me problems we'll it hadn't been all this started w my coolant temp sensor I can't believe other wiring issues I've got I'm grateful and feeling pretty confident LoL ty so much
Wherever it will fit and not get torn up or burnt up pretty much. You just want one on the leftside and one on the right-side of the engine. Chevy had the knock sensor on the side of the engine for a long time and it was easy to access. This was a bad design change to put them under the intake.
Yes I used two new sensors. I just threaded one sensor into the left side of the block and one sensor into the back right when facing the engine. Essentially there are several open threaded spots on the block at the front and rear that the sensors can thread into. I just took an old sensor and found a spot it would thread into so not to damage the new ones. If the sensor fit and snugged down that was the spot. I choose those two spots because that way I didn't have to cut or extend the wire harness. Just snug the sensors down and a turn a little more to be sure there was no need to torqure them.
Thank you Im right in the middle of this issue now with an 04 tahoe. I really appreciate your help and taking the time to answer. Ive tried one bipass meathod and it didnt work for me. . Thanks again
@@41663hello I have an 04 Tahoe and was wondering if you were able to do what the video did I do not want to take the manifold off and I just needed to pass inspection
There are actullay numerous spots on the backside and the side that the sensors can screw into. They are threaded and are the same size threads as the sensors. I chose one on the right side at the top backside when facing the engine and the top leftside when facing the engine. I was going to try some in the front of the engine but I didn't want to have to cut into the harness. I was only able to reach them from underneath the truck. The engines are designed this way for different models for different accessories to be added. If you have ever seen an engine on an engine stand you would see all the available spots.
If you don't want a knock sensor sure. It would become a fixed wire that does nothing. I would not suggest or recommend it. A knock sensor is needed to pickup early signs of engine trouble or wear that may not be audible. It will change resistance as a vibration is detected triggering the check engine light thus preventing possible major engine problems.
Hi, Book says 14 ft lbs but I personally wrench tighten until they are good and snug. I recommend the book specs if you haven't been working on cars since you were ten and have a good solid feel for tightening Knock Sensors. Kinda like a spark plug.
