Well done. Thank you for the information. Your a good man for sharing information like this to people who cannot afford to get their vehicles done in a shop. I know that sometimes, troubleshooting gets a bit expensive when you don't really understand the component and its function and relation to other components. The understanding or knowledge is the reason why mechanics gets the same bad rep as car salesman. Mechanic's lack the knowledge (or does not want to update their skills) and their trial and error style of troubleshooting results in the expense getting out of control which makes the costumer unhappy and doubtful. Well to make this short, there are 3 kinds of mechanics out there: 1 - the trial and error kind; 2 - the know what the problem but makes it look really bad to get more money; and 3 - your kind of a mechanic, the kind that has good principles (willing to share knowledge and for sure fair enough to customers). Your a good man. thanks again
Your channel might not be the most popular in the Automotive category, but you are actually the best and most enjoyable without a doubt! Thanks for all the awesome videos, I appreciate the hell out of your narrations.
Thanks in large part to your great videos, Brian, my '95 Honda Accord EX with nearly 300k miles is running tip top. Thanks especially for your Accord VTEC water pump replacement video. I jumped in way over my head with that one and your video helped me through it and saved my car. Now with nothing to fix at the moment, I still watch your videos (like this one) to: 1) become more knowledgeable in general when it comes to cars and 2) for pure entertainment value! You should be on prime time television my friend. Thanks so much for doing these videos... I know a lot of hard work goes into filming and editing each one. It is greatly appreciated. Peace!
You are a very talented teacher. Lot of very smart guys making videos but don't have a natural ability to teach. I rate you up there with ETCG, SCANNER DANNER, REALFIXES REALFAST, SMA, Mandy ETC. I'm grateful Brian, thank you.
Great explanation video, Brian! I like the knock sensor bench test with the vice. The only thing you really need to confirm proper knock sensor operation is an OSCILLOSCOPE! The voltmeter on the AC scale only gives you a general amplitude of the signal. A faulty knock sensor may still produce the right amplitude, but the signal will be very erratic and choppy instead of a smooth sine wave. Recently had an '01 Lexus RX300 in the shop with an intermittent P0330-Knock Sensor Bank 2 code. On the bench, both B1 and B2 sensors showed a similar signal. However, zooming in on the waveforms, B2 looked more like a ragged square wave compared to B1 which was a smooth sine wave...pretty awesome. No other way to confirm the fault. Knowledge is power!
Hey Ivan do the new style knock sensors on Chevy ls3 ever fail to sense detonation and end up causing the timing to advance too much or do I have another problem if I have detonation
The technology in use in the knock sensor was invented by French Physicist Paul Langevin in 1917 and was first used to detect submarines underwater. All the components of it had been studied since the 1890's, but he was was the first one to put it all together.
Thank you Brian. My Toyota Tacoma has a knock sensor P0325 fault. Fortunately it's a 2.7 4- cylinder. With a low profile ratchet i can R&R hopefully with out removing intake. A neahbor walked up and said "hay you got hesitation when you accelerate after shifting down?" I said YES but my scanner said it's the knock sensor. He said he repaced the No.4 spark plug wire and that solves the problem. HOLY SMOKES my spark plug wires are original. Stay tuned and thank you again. Conrad
Hey Brian, great work!!! i think knock started appearing mainly due to the low octane fuels as lead was banned (being toxic and damaging the catalytic converters). Cheers!
Got a po325 on 98 honda prelude. Noticed harness connection coated in oil. Will clean and see if code comes back. If it comes back will replace with oem. Best video out there on knock sensors.
Thanks a ton for the video, I just went through the painstaking process of replacing the knock sensors on a 06 2500HD. I went with the OEM from the dealership (GM Part No.), Bench tested both with a multimeter before install and at various points during installation. So far so good!
Brian I have had good luck with Standard/Bluestreak knock sensors for LS engines. Last one I did was my own 2500hd. I have yet been able to remove the harness connector without it shattering so I always order a new harness. It's quite expensive paying someone to change them out so going with a factory part is probably worth it. Great info 👍
WOW, the actual internal of the sensor is soooo crazy. Sorta of xtal microphone ... Thanks, really the best vid on knock I ve ever seen. You never dissapoint !!!!
thank you so much for your videos. I went to change my wife's breaks and was immediately presented with your dodge journey brake video I looked up knock sensor and here you are again. Please keep them coming Brian, I know jack crap and appreciate all your help.
Yes watch the Delco sensor the top crimp will not hold and rotate break connection on 100 k resitor . I have been using the gm oem cost more but cheaper than doing job twice.
Brian! Not the one to be picky because I love your informative videos, but you said turbo cars and supercharged cars want higher compression ratios. Technically they want lower compression to reduce strain in the bottom end (talking specifically petrol cars), hence the reason of not being able to turbo factory non turbo cars. Though a higher compression ratio on low boost pressure (turbo/supercharged) is much more efficient then it's N/A version with the same compression ratio (hence, where the diesel cars fit in)
Nik Trp When he said that I was waiting for someone to say this. I don't agree with you, he was technically correct. If you are talking static compression ratio (CR) then yes, forced induction (FI) wants a low CR. However what really matters is the Dynamic CR, which on a FI car will be (almost always) higher than the N/A version. The static CR is a fairly useless term when talking about pre detonation.
So much fail here. The reason old cars don't have knock sensors is because they don't have computers so there's nothing for the sensor to 'talk' to, not because of the compression ratios. Plenty of old cars had knock problems for various reasons and some old high performance engines had higher compression ratios than some new engines. "low octane fuel doesn't burn completely, doesn't burn easily"; these two statements are completely false, low octane fuel ignites more easily than high octane and generally will leave less residue than high octane will. High octane fuels often have other additives to help reduce the left over residues so that they're not left in the engine, but they can still be dirtier burning than low octane fuel. High octane fuel reduces the likely hood of detonation because it is harder to ignite than low octane fuel. Detonation caused by carbon and self ignition as you described with the campfire effect can't be eliminated by a knock sensor retarding the timing since the spark isn't what's igniting the fuel, luckily this doesn't happen much with modern fuels and modern engines. "gotta have higher compression ratios if you wanna run turbo chargers and superchargers" Another thing that could be no further from the truth. Compression ratios in supercharged and turbo charged engines is almost always lower than in naturally aspirated engines to allow more power with reduced chances of detonation.
considering the knock sensor is an electrical sensor. shouldnt i be able to open it up and repair it myself by replacing the piezoelectric crystal and the weight, wich ever is faulty. i think i can do it
Theoretically yes. Getting inside, fixing it, and resealing it would be pretty tough. Make a video if you decide to try it. I just replaced one and may tear into the old one just to see how doable that would be, but the way it's mounted on the motor I was working on (big job to get to it) I didn't want to experiment so I went with OE from the dealer.
@@danielb3552 If you didn't have the right crystal it would probably be too sensitive or not sensitive enough. Assuming the crystal is fine, the spring could weaken over time or the seal could fail causing the resistor or something else to corrode. I do wonder what is the cause of failure.
Thank you for all the information I have a 1994 suburban with 294,000 miles on it with OBD1 , I am getting code 43 I replaced the knock sensor and I am still getting code 43. God Bless you
You're video on smoking engine was great too. I'm losing water and oil with no visible leak. Rebuild or junk it? 2005 Sioverado 5.3 crew cab 4x4 with 195k miles
Back in the day... there have always been 2 knock sensors for your engine. They are installed on your head. One on the left and one on the right, typically. Their effectiveness was determined by each persons exposure to and duration of very loud noises like rock music, heavy equipment, etc. Mine are 60 years old and still work, although I do have some ringing in them now. He he...
In the old days you don't have any thing like sensor or anything they put they in your car so they can' rip you enywhay delete and it will stay out you ok but now if you have the light on they don't inspect you car so that is a clown story
Also, the white spots in your finger nails most likely due to a zinc/magnesium defeiciency. Might want to get on a supplement. Gotta keep you healthy, you are important to us...
Good vid. Lots of info but I respectfully disagree with 2 things... Knock sensors came with fuel deregulation after 1978 when pump gas went from 103 octane premium down to 87 octane regular. Octane level determines gasoline's resistance to detonation. Compression was lowered initially, but much power was lost. Computers and sensors allowed some of that to be reclaimed. Next item- turbo and blower engines are usually LOW static compression. This allows more room in the combustion chamber for a bigger air/fuel charge. Your compression is determined by the speed and ratio of your supercharger or turbo. Your rpm is limited by the fuel's octane and where detonation begins. An engine with higher compression will have less power gain by adding a turbo/blower than a low compression engine. A naturally aspirated engine with 10:1 compression will make more HP on a dyno using 93 octane than it will using 110 octane race gas. Proven fact. Excessive octane slows the rate of combustion and makes less power. Use just enough octane for your compression ratio and no more and you will make more power.
Guess I'll pony up the $1500 to have them changed on my 19 year old V6 Toyota. Got a check engine light code for caused by one of them. The harness also should be changed.
Very good and easy to understand video. Thanks for the time and effort that you took to help me and thousands of others to understand this simple concept.
There's detonation . when the mixture explodes . and preignition when the mixture is ignited by something other than the spark plug. Preignition is what holes a piston it can occur way before tdc. Causing a tremendous pressure spike . detonation melts the piston at the side . you can also have pre ignition induced detonation.
Thank you for putting up this video , make me more to understand about the knock sensor work It’s very good video and very good explanation Can I ask you a question This knock sensor which we have to test resistance I saw another video it said that if the knock sensor has a resistance is bad sensor, is it true
Thank you so much for the great explanation Brian!! Is there a way to bypass the knock sensor other than taking it apart and installing the resistor in series with the sensor? Thanks in advance!!
First time I heard about the hydrocarbons building up to cause knocking. Also the reasoning to get the factory part. p0327 came up on my 05 Rainier. Runs fine though.
Would bad knock sensors cause the truck to not go over 2k rpm? And also for it to die when you rev it and it idles down? But the truck can rev out when in 1 and 2 gear but still struggles in 3 but it also dies sometimes in reverse. Any help would be appreciated. I brought it to auto parts stire and they plugged in computer and it read knock sensors out and clavicle purge valve
I cannot find my sensor, I know its on the passengers side, down near where the spark plug wires start, on the lower part of the engine..can someone show me where. I have a Chevy S10 year 2000, and the 4 cylinder engine, auto tranny. I see nothing sticking out of the engine like he had at 5:30 in the video for a chevy.
12:30 you mention 5v reference. well yes but no.only on multiple wire versions. on single wire.. ecm only checks for the ground through the sensor. the computer looks for that specific resistance.
I had a knock sensor bank 2 code come up on my 8.1L 2002 Chevy and so I went to orielly auto parts and got 2 new knock sensors and put them in and now it throws a bank 1 code and sometimes a bank 2 code also I should have mentioned that when I took out the bank 2 sensor the first time its pluggin connection was all rusty.. So that explains why it threw the code the first time.. But why is it throwing a code for both sides now? Also my knock sensors are mounted down on the sides of the engine by the oil filter and starter.
what are symptoms of knock sensor....i looked at '02 honda CRV today and it sounded like the lifters or something was knocking......so i didnt buy it...would knock sensor sound like something knocking in engine....?
Can this cause idle issues...like a low idle and a surge? I have an 07 Subaru Impreza outback sport I cannot find a TPS or a AIC sensor...my last stop is the MAP.
Hey Brian Good lesson You have teach us a lot Would it possible for you provide series of lesson on automotive sensors I would truly appreciate your effort in helping us to deep dive in automotive concepts
This is a crazy question but I have a 2003 safari van and It has some pinging on acceleration after reaching normal operating temperature . I have a heat shield above the tailpipe that is hanging down on one end and rattling on the tailpipe . Is it possible that the knock sensor is picking this up and adjusting for knock and actually causing it to ping ? Probably not right ! Most likely a bad knock sensor. You say chevy takes two sensors but I have been told the 2003 4.3 V6 only has one ? I also considered The EGR valve as possibly the problem , but apparently the 2003-2005 safari and astro 4.3 no longer have EGR valves but have a different system. Would appreciate any help from anyone on this. For starters where exactly is the knock sensor on the 2003 4.3 v6 ? Been told it's on the back of motor others say the lower side some say under the intake ?
THANKS FOR THE INFO. AM I UNDERSTANDING THIS CORRECTLY? ARE THE KNOCK SENSORS ESSENTIALLY USELESS? I DRIVE AN 06 25OOHD GMC. IF PREIGNITION IS AN ISSUE WOULDN'T ENGINE PERFORMANCE SUCK AND RUN A BIT ROUGH?
rebuilt a 93 chevy c1500 4.3 engine,, it had a rusty old knock sensor.. I put a brand new one in,, at the parts store, there were 2 available for my model, but different part numbers that cross referenced to two DIFFERENT OEM part numbers.. ., the one they gave me doesnt seem to work., I get an immediate code 043 that will not clear.. I have 5 volt reference to the wire going to the sensor, but when I hook the wire up, I dont get a voltage drop to 2.5 volts.. it stays a steady 5 volts DC.. I performed the resistance test on the sensor itself. . and get 0 continuity, the service manual indicates I should get around 3900 ohms.. Im trying to figure out if I either recieved a defective sensor. OR I recieved the wrong sensor.. the service literature says a steady circuit proving voltage goes thru the sensor and wiring from the ECM.. with key on or engine running.,,,, If the sensor cannot let voltage flow thru it, theres no way I can see it can complete the circuit. the choices are gm 10456031 or 10456018 .. I cannot find ant service info that tells the difference between the two sensors. As I understand it, the ECM sends out the 5 volt reference signal to the knock sensor, and the resistor inside of the knock sensor decreases the dc voltage, according to what the ECM expects to see. I think it has to work as a feedback, because its a single wire system that completes its path of ground, thru the engine block, ground wires, and back to the ECM. Im finding that different knock sernsors may have different resistors in them,, some Gms have 100k, some 89k, some 39k. theres a heck of alot more to knock sensors that I previously thought.
I have a similar problem. I replaced my sensors and harness, but I still get low voltage codes on both sensors, but only after driving on the highway. Are they bad sensors, it the threadlocker causing it?
Prefer cars with engines that do not have the knock sensor at all both turbo and non-turbo . They feel the knocks through ionization of the spark plugs. One less thing that can give up and cause trouble codes .
Could you test a sensor like the first kind you showed without taking it out of the block ? In other words, hook the ground of the meter to the block, and the positive lead to the pin on the knock sensor, and tap on the block ? Would that work or is it necessary to pull it from the engine block ?
That's a good question,I through a code on my ST1300 Honda ,so I've been researching it, and some guy tested it while installed and running at idle and four thousand rpm's. He determined sensor was fine.replaced ECM for the fix.
Hey Brian how are you thanks for the information but I had a question for you, do you know if the knock sensor can ge damage if the wire harnes get naked (wires exposed or not isolation) and hit or make contact with the engine or body of the car ? Thanks for the answer in advance and hopefully you understand me
Is it possible to hve knocking oonly in clod start ? ,,after all day on part start like cat smooth and quite, but early morningnext day i hear 1-2min of knocking...Any tip pls?
question! if there is a knock, does the pressure in the cylinder rise above what would be the maximum created under normal (ie without knock) conditions during the entire cycle?
Got a 94 Chevy Silverado sets a code 43. Which is knock sensor any way to trick the knock sensor since I can't get it off to replace. Everything else has been worked on . I'm not going into everything, but you probably know. Thanks
94 Fleetwood 350. The car runs like a dream, I get to half peddle and runs like a manual in 4th gear while driving 10mph. I replaced almost all the sensors, ignition, air and fuel line. No codes. Does my issue sound like auto ignition from carbon and bad knock sensors?
Good morning. I'm working on a 2005 Honda Accord 2.4 that is not charging properly and yesterday someone told me that one of the components to check out it's the cam sensor . and make me think 🤔 what it cam sensor have to do to alternator not charging properly 😞
Question I have a nitrous fox went with Fitech and a wet plate 100 jet in it can I install a knock sensor to keep a watch on it when I spray ? Where would I install it
Yes Stefan the ECM supplies +5v, the reason may be the ECM operates better with the AC signal generated from the peizo element biased at a DC voltage, it may have something to do with a better signal to noise ratio. If you want to check for yourself, just turn the ignition on (engine not running) with the knock sensor disconnected and measure the voltage on the wire from the ECU. If you measure the voltage with the wire connected (again with ignition on and engine NOT running) the voltage will be lower due to the voltage drop across the internal 100k resistor inside the knock sensor which is connected to earth (thus completing the circuit).
Man I wish you could have shown an old wrist watch alarm piezo. It works basically in the opposite way. The speaker becomes the microphone. Only made for high frequency so must be something in the pre fire sound it's picking up that's high frequency?
hi I have a 03 single cab silverado with a check engine light on it because I need to replace knock sensor is it true if once I replace it, it will give me truck more power and save gas?
Great video. Thanks for taking the time to make this. Very helpful. Question: Does a P0325 error code indicate a faulty Knock Sensor? Or does it mean that the sensor is detecting knock on the block?
brian. how bad can a knock sensor make a motor run. my 98 5.7 vortec has a constant misfire on 3 cylinders through all rpms. it runs so bad I can only go about 30 mph. new distributor cap and rotor, wires and plugs, new mpi spider assembly. had compression test on cylinders done, fuel pressure tests out. please any good info is appreciated
Tommy Jones make sure your injector plugs are plugged in and locked in. it can cause misfire of the plugs aren't in all the way. plus make sure your dist cap ate locked down tight. it's common fail among vortec v8s, I own two suburban. I know every nook and cranny about them.
does it cause bad engine proformance. My 2004 chevy 2500 6.0 seems like it drags and doesn't have the power it should. The knock sensors are showing up in the codes. Bank 1 and bank 2.
Darrell Norman those are common to fail, cuz water ingress in the sensors between the Valley. replace them and seal it with silicone. put everything back. you're good.
Hey Brian I had a question. When you said you ruled out the knock sensor on the 5.3 did you mean that it was the problem? Cause I'm having the exact issue on my 5.3 at 70mph that I'm currently trying to diagnose and only can get it to do it at that speed. And also I saw you at the Utah auto expo by the Nissan Titan diesel!!!
My knock sensors are working it’s a new build on my s10 when I dropped a Engin I got it from a junkyard I never really tested it or did a compression check but I do hear a pinging sound and when I accelerate it backfires, I definitely hear a bad Lifter
2007 Toyota 4Runner they are inside the engine. I'm getting a code that says knock sensor. Do you think the average person should attempt this that has tools and some knowledge of what you definitely have a mechanic do it? For my vehicle it was like $1200. Please respond thank you
I just replaced my knock sensor and siring harness on a 2003 Chevy 1500 5.3 when I replaced my intake manifold gasket. Got it all put back together and it runs alot better. Then I drove it for est. 100 miles and the check engine light came on. I read the code and it say knock sensor low voltage. Do you have any idea what causes this?
We did a knock sensors (AC Delco) on my 5.3L L33 engine and I still throwing codes for the knock sensors! My brother has been a great mechanic for easily 30 years and my truck is got us both scratching our heads! He's looked things up online on one of those main companies. I have low power (not able to power break - No burn out! ), getting 12 miles to gallon, we tried to bypass with to other sensors just to get it to pass inspection & no luck! And have you ever heard an hour meter reset itself? Because it has with mine. Maybe you can give me some ideas? Thanks for reading this.
@@kevinlonghurst631 I've not heard about any of the diesels hour meter resetting itself to zero like mine did! If there's any GM mechanics out there that could check into that & give us some insight to what could be done to fix it or just simply what happened!?? It would be greatly appreciated! Thanks
Brian thanks so much for this video. Great stuff man!!! Question, I have a 1999 K1500 Suburban. Does it have 2 knock sensors? A friend of mine stated that it only has 1 and it's located underneath the engine...?
Brian.....where are you located..........I got a check engine light that comes on and believe that the knock sensor is the problem.............2010 Cadillac SRX
Well done. Thank you for the information. Your a good man for sharing information like this to people who cannot afford to get their vehicles done in a shop. I know that sometimes, troubleshooting gets a bit expensive when you don't really understand the component and its function and relation to other components. The understanding or knowledge is the reason why mechanics gets the same bad rep as car salesman. Mechanic's lack the knowledge (or does not want to update their skills) and their trial and error style of troubleshooting results in the expense getting out of control which makes the costumer unhappy and doubtful. Well to make this short, there are 3 kinds of mechanics out there: 1 - the trial and error kind; 2 - the know what the problem but makes it look really bad to get more money; and 3 - your kind of a mechanic, the kind that has good principles (willing to share knowledge and for sure fair enough to customers). Your a good man. thanks again
Your channel might not be the most popular in the Automotive category, but you are actually the best and most enjoyable without a doubt! Thanks for all the awesome videos, I appreciate the hell out of your narrations.
Thanks in large part to your great videos, Brian, my '95 Honda Accord EX with nearly 300k miles is running tip top. Thanks especially for your Accord VTEC water pump replacement video. I jumped in way over my head with that one and your video helped me through it and saved my car. Now with nothing to fix at the moment, I still watch your videos (like this one) to: 1) become more knowledgeable in general when it comes to cars and 2) for pure entertainment value! You should be on prime time television my friend. Thanks so much for doing these videos... I know a lot of hard work goes into filming and editing each one. It is greatly appreciated. Peace!
You are a very talented teacher. Lot of very smart guys making videos but don't have a natural ability to teach. I rate you up there with ETCG, SCANNER DANNER, REALFIXES REALFAST, SMA, Mandy ETC. I'm grateful Brian, thank you.
Great explanation video, Brian! I like the knock sensor bench test with the vice. The only thing you really need to confirm proper knock sensor operation is an OSCILLOSCOPE! The voltmeter on the AC scale only gives you a general amplitude of the signal. A faulty knock sensor may still produce the right amplitude, but the signal will be very erratic and choppy instead of a smooth sine wave.
Recently had an '01 Lexus RX300 in the shop with an intermittent P0330-Knock Sensor Bank 2 code. On the bench, both B1 and B2 sensors showed a similar signal. However, zooming in on the waveforms, B2 looked more like a ragged square wave compared to B1 which was a smooth sine wave...pretty awesome. No other way to confirm the fault. Knowledge is power!
Hey Ivan do the new style knock sensors on Chevy ls3 ever fail to sense detonation and end up causing the timing to advance too much or do I have another problem if I have detonation
motoYam82
Does an 03 durango 4.7 have a knock sensor?
The technology in use in the knock sensor was invented by French Physicist Paul Langevin in 1917 and was first used to detect submarines underwater. All the components of it had been studied since the 1890's, but he was was the first one to put it all together.
Thank you Brian. My Toyota Tacoma has a knock sensor P0325 fault. Fortunately it's a 2.7 4- cylinder. With a low profile ratchet i can R&R hopefully with out removing intake. A neahbor walked up and said "hay you got hesitation when you accelerate after shifting down?" I said YES but my scanner said it's the knock sensor. He said he repaced the No.4 spark plug wire and that solves the problem. HOLY SMOKES my spark plug wires are original. Stay tuned and thank you again. Conrad
Hey Brian, great work!!! i think knock started appearing mainly due to the low octane fuels as lead was banned (being toxic and damaging the catalytic converters). Cheers!
Got a po325 on 98 honda prelude. Noticed harness connection coated in oil. Will clean and see if code comes back. If it comes back will replace with oem. Best video out there on knock sensors.
Thanks a ton for the video, I just went through the painstaking process of replacing the knock sensors on a 06 2500HD. I went with the OEM from the dealership (GM Part No.), Bench tested both with a multimeter before install and at various points during installation. So far so good!
Brian I have had good luck with Standard/Bluestreak knock sensors for LS engines. Last one I did was my own 2500hd. I have yet been able to remove the harness connector without it shattering so I always order a new harness. It's quite expensive paying someone to change them out so going with a factory part is probably worth it. Great info 👍
WOW, the actual internal of the sensor is soooo crazy. Sorta of xtal microphone ... Thanks, really the best vid on knock I ve ever seen. You never dissapoint !!!!
In case you are wondering if your car knocks: Get ELM327 BT OBD adapter, Torque App for your smartphone and "Knock Detector" plugin for Torque App.
I've used that. :) It only works if the knock sensor is working. I drove a couple test runs where I knew I'd get knocking. Confirmed the problem. :)
thank you so much for your videos. I went to change my wife's breaks and was immediately presented with your dodge journey brake video I looked up knock sensor and here you are again. Please keep them coming Brian, I know jack crap and appreciate all your help.
Yes watch the Delco sensor the top crimp will not hold and rotate break connection on 100 k resitor . I have been using the gm oem cost more but cheaper than doing job twice.
Brian! Not the one to be picky because I love your informative videos, but you said turbo cars and supercharged cars want higher compression ratios. Technically they want lower compression to reduce strain in the bottom end (talking specifically petrol cars), hence the reason of not being able to turbo factory non turbo cars. Though a higher compression ratio on low boost pressure (turbo/supercharged) is much more efficient then it's N/A version with the same compression ratio (hence, where the diesel cars fit in)
Nik Trp This. Also, low octane fuel doesn't leave burnt deposits in your cylinder, any fuel can, specifically lower quality gasoline regardless of octane.
Nik Trp I should have known that. Thanks for bringing that up.
User Name It's incomplete burn. That could be many things.
briansmobile1 agreed, even oil entering the center. However on an otherwise healthy engine my first choice is poor fuel.
Nik Trp When he said that I was waiting for someone to say this. I don't agree with you, he was technically correct. If you are talking static compression ratio (CR) then yes, forced induction (FI) wants a low CR.
However what really matters is the Dynamic CR, which on a FI car will be (almost always) higher than the N/A version. The static CR is a fairly useless term when talking about pre detonation.
So much fail here.
The reason old cars don't have knock sensors is because they don't have computers so there's nothing for the sensor to 'talk' to, not because of the compression ratios. Plenty of old cars had knock problems for various reasons and some old high performance engines had higher compression ratios than some new engines.
"low octane fuel doesn't burn completely, doesn't burn easily"; these two statements are completely false, low octane fuel ignites more easily than high octane and generally will leave less residue than high octane will. High octane fuels often have other additives to help reduce the left over residues so that they're not left in the engine, but they can still be dirtier burning than low octane fuel. High octane fuel reduces the likely hood of detonation because it is harder to ignite than low octane fuel.
Detonation caused by carbon and self ignition as you described with the campfire effect can't be eliminated by a knock sensor retarding the timing since the spark isn't what's igniting the fuel, luckily this doesn't happen much with modern fuels and modern engines.
"gotta have higher compression ratios if you wanna run turbo chargers and superchargers" Another thing that could be no further from the truth. Compression ratios in supercharged and turbo charged engines is almost always lower than in naturally aspirated engines to allow more power with reduced chances of detonation.
his brain is fried
considering the knock sensor is an electrical sensor. shouldnt i be able to open it up and repair it myself by replacing the piezoelectric crystal and the weight, wich ever is faulty. i think i can do it
Theoretically yes. Getting inside, fixing it, and resealing it would be pretty tough. Make a video if you decide to try it. I just replaced one and may tear into the old one just to see how doable that would be, but the way it's mounted on the motor I was working on (big job to get to it) I didn't want to experiment so I went with OE from the dealer.
DonziGT230 +
@@danielb3552 If you didn't have the right crystal it would probably be too sensitive or not sensitive enough. Assuming the crystal is fine, the spring could weaken over time or the seal could fail causing the resistor or something else to corrode. I do wonder what is the cause of failure.
Thank you for all the information I have a 1994 suburban with 294,000 miles on it with OBD1 , I am getting code 43 I replaced the knock sensor and I am still getting code 43. God Bless you
You're video on smoking engine was great too. I'm losing water and oil with no visible leak. Rebuild or junk it? 2005 Sioverado 5.3 crew cab 4x4 with 195k miles
Back in the day... there have always been 2 knock sensors for your engine. They are installed on your head. One on the left and one on the right, typically. Their effectiveness was determined by each persons exposure to and duration of very loud noises like rock music, heavy equipment, etc. Mine are 60 years old and still work, although I do have some ringing in them now. He he...
In the old days you don't have any thing like sensor or anything they put they in your car so they can' rip you enywhay delete and it will stay out you ok but now if you have the light on they don't inspect you car so that is a clown story
Also, the white spots in your finger nails most likely due to a zinc/magnesium defeiciency. Might want to get on a supplement. Gotta keep you healthy, you are important to us...
You give great clear info as always. My 06 Cadillac DTS pings it's butt off under heavy load on 93 octane, but no codes. Evidently all carboned up.
Good vid. Lots of info but I respectfully disagree with 2 things... Knock sensors came with fuel deregulation after 1978 when pump gas went from 103 octane premium down to 87 octane regular. Octane level determines gasoline's resistance to detonation. Compression was lowered initially, but much power was lost. Computers and sensors allowed some of that to be reclaimed. Next item- turbo and blower engines are usually LOW static compression. This allows more room in the combustion chamber for a bigger air/fuel charge. Your compression is determined by the speed and ratio of your supercharger or turbo. Your rpm is limited by the fuel's octane and where detonation begins. An engine with higher compression will have less power gain by adding a turbo/blower than a low compression engine. A naturally aspirated engine with 10:1 compression will make more HP on a dyno using 93 octane than it will using 110 octane race gas. Proven fact. Excessive octane slows the rate of combustion and makes less power. Use just enough octane for your compression ratio and no more and you will make more power.
Guess I'll pony up the $1500 to have them changed on my 19 year old V6 Toyota. Got a check engine light code for caused by one of them. The harness also should be changed.
Suck Squeeze Bang Blow ...words to live by.
I used to manufacture the Knock sensor Body on a multispindle turning machine in the 1990`s when I worked for TRW :)
Very cool when guys like you are willing to spend your time helping others. Cheers
Thank you so much for all this information. It’s really help me a lot to take care of my issues. I appreciate you.
Very good and easy to understand video. Thanks for the time and effort that you took to help me and thousands of others to understand this simple concept.
There's detonation . when the mixture explodes . and preignition when the mixture is ignited by something other than the spark plug. Preignition is what holes a piston it can occur way before tdc. Causing a tremendous pressure spike . detonation melts the piston at the side . you can also have pre ignition induced detonation.
Brian best video ive seen in a while!top man
@11:11 how do you test the voltage going to the Knock sensor from the computer?
Thank you for putting up this video , make me more to understand about the knock sensor work
It’s very good video and very good explanation
Can I ask you a question
This knock sensor which we have to test resistance
I saw another video it said that if the knock sensor has a resistance is bad sensor, is it true
Thank you so much for the great explanation Brian!! Is there a way to bypass the knock sensor other than taking it apart and installing the resistor in series with the sensor? Thanks in advance!!
First time I heard about the hydrocarbons building up to cause knocking. Also the reasoning to get the factory part. p0327 came up on my 05 Rainier. Runs fine though.
Absolutely the best Knock Sensor Video on TH-cam!
Great explanation!
Galium phosphate, you said produces energy when squeezed. Isn't that's what was in kids shoes 20 years ago that lights lit up when stepped?
VictoRoy i wish it was the truck i was working on but it was an infiniti and the way to sensors was a whole other beast. Thanks though
Welcome Chris!
that is very good , I have been fighting my 95 f150 4.9 and this fixed the spark knock!
Would bad knock sensors cause the truck to not go over 2k rpm? And also for it to die when you rev it and it idles down? But the truck can rev out when in 1 and 2 gear but still struggles in 3 but it also dies sometimes in reverse. Any help would be appreciated. I brought it to auto parts stire and they plugged in computer and it read knock sensors out and clavicle purge valve
absolutely brilliant video on knock sensor with additional graphics kept me attentive. well done,.
I cannot find my sensor, I know its on the passengers side, down near where the spark plug wires start, on the lower part of the engine..can someone show me where. I have a Chevy S10 year 2000, and the 4 cylinder engine, auto tranny. I see nothing sticking out of the engine like he had at 5:30 in the video for a chevy.
12:30 you mention 5v reference. well yes but no.only on multiple wire versions. on single wire.. ecm only checks for the ground through the sensor. the computer looks for that specific resistance.
Thanks Mister sir I heard about the nock sensor but I had no idea it was such an important piece of the ingine thanks again.
I had a knock sensor bank 2 code come up on my 8.1L 2002 Chevy and so I went to orielly auto parts and got 2 new knock sensors and put them in and now it throws a bank 1 code and sometimes a bank 2 code also I should have mentioned that when I took out the bank 2 sensor the first time its pluggin connection was all rusty.. So that explains why it threw the code the first time.. But why is it throwing a code for both sides now? Also my knock sensors are mounted down on the sides of the engine by the oil filter and starter.
what are symptoms of knock sensor....i looked at '02 honda CRV today and it sounded like the lifters or something was knocking......so i didnt buy it...would knock sensor sound like something knocking in engine....?
Can this cause idle issues...like a low idle and a surge? I have an 07 Subaru Impreza outback sport I cannot find a TPS or a AIC sensor...my last stop is the MAP.
Can you tell me why I still get a knck sensor code and I replaced both of them? 2002 chevy avalanche
What if after I replaced my knock sensor still giving me the code for that??? What else can I do????
same problem here on a saturn outlook 2007 would be nice to hear from Brian about this going crazy
Great video. I replaced one on our Honda, only to have it come back on! Now I know why. thanks!
Great video. I wish someone would do one on the two pin wide band sensor. At least I think it's a wide band, it's out of a1989 ford f150 5.0.
Hey Brian
Good lesson
You have teach us a lot
Would it possible for you provide series of lesson on automotive sensors
I would truly appreciate your effort in helping us to deep dive in automotive concepts
This is a crazy question but I have a 2003 safari van and It has some pinging on acceleration after reaching normal operating temperature . I have a heat shield above the tailpipe that is hanging down on one end and rattling on the tailpipe . Is it possible that the knock sensor is picking this up and adjusting for knock and actually causing it to ping ? Probably not right ! Most likely a bad knock sensor. You say chevy takes two sensors but I have been told the 2003 4.3 V6 only has one ? I also considered The EGR valve as possibly the problem , but apparently the 2003-2005 safari and astro 4.3 no longer have EGR valves but have a different system. Would appreciate any help from anyone on this. For starters where exactly is the knock sensor on the 2003 4.3 v6 ? Been told it's on the back of motor others say the lower side some say under the intake ?
THANKS FOR THE INFO. AM I UNDERSTANDING THIS CORRECTLY? ARE THE KNOCK SENSORS ESSENTIALLY USELESS? I DRIVE AN 06 25OOHD GMC. IF PREIGNITION IS AN ISSUE WOULDN'T ENGINE PERFORMANCE SUCK AND RUN A BIT ROUGH?
rebuilt a 93 chevy c1500 4.3 engine,, it had a rusty old knock sensor.. I put a brand new one in,, at the parts store, there were 2 available for my model, but different part numbers that cross referenced to two DIFFERENT OEM part numbers.. ., the one they gave me doesnt seem to work., I get an immediate code 043 that will not clear.. I have 5 volt reference to the wire going to the sensor, but when I hook the wire up, I dont get a voltage drop to 2.5 volts.. it stays a steady 5 volts DC.. I performed the resistance test on the sensor itself. . and get 0 continuity, the service manual indicates I should get around 3900 ohms.. Im trying to figure out if I either recieved a defective sensor. OR I recieved the wrong sensor.. the service literature says a steady circuit proving voltage goes thru the sensor and wiring from the ECM.. with key on or engine running.,,,, If the sensor cannot let voltage flow thru it, theres no way I can see it can complete the circuit. the choices are gm 10456031 or 10456018 .. I cannot find ant service info that tells the difference between the two sensors. As I understand it, the ECM sends out the 5 volt reference signal to the knock sensor, and the resistor inside of the knock sensor decreases the dc voltage, according to what the ECM expects to see. I think it has to work as a feedback, because its a single wire system that completes its path of ground, thru the engine block, ground wires, and back to the ECM. Im finding that different knock sernsors may have different resistors in them,, some Gms have 100k, some 89k, some 39k. theres a heck of alot more to knock sensors that I previously thought.
I have a similar problem. I replaced my sensors and harness, but I still get low voltage codes on both sensors, but only after driving on the highway. Are they bad sensors, it the threadlocker causing it?
1994 ford f150 5.0 liter v8 just starting out stepping on accelerator truck hesitates almost like a stall but then goes and drives fine. any ideas
Prefer cars with engines that do not have the knock sensor at all both turbo and non-turbo . They feel the knocks through ionization of the spark plugs.
One less thing that can give up and cause trouble codes .
Could you test a sensor like the first kind you showed without taking it out of the block ? In other words, hook the ground of the meter to the block, and the positive lead to the pin on the knock sensor, and tap on the block ? Would that work or is it necessary to pull it from the engine block ?
That's a good question,I through a code on my ST1300 Honda ,so I've been researching it, and some guy tested it while installed and running at idle and four thousand rpm's. He determined sensor was fine.replaced ECM for the fix.
I'm gonna share my new found knowledge with the world and seem like a genius. Thanks Brian.
Hey Brian how are you thanks for the information but I had a question for you, do you know if the knock sensor can ge damage if the wire harnes get naked (wires exposed or not isolation) and hit or make contact with the engine or body of the car ? Thanks for the answer in advance and hopefully you understand me
Is it possible to hve knocking oonly in clod start ? ,,after all day on part start like cat smooth and quite, but early morningnext day i hear 1-2min of knocking...Any tip pls?
Why sent 5 volt from the ECM to Knock sensor ?
Hey Brian if I over tighten the knock sensor and it spins within its self did I break it? I did it in a 92 Chevy truck 350 5.7
Thank bud!!! Great vid and hats off to Mandy.
question! if there is a knock, does the pressure in the cylinder rise above what would be the maximum created under normal (ie without knock) conditions during the entire cycle?
What up friend I change my knock sensor on my 01 chevy silverado but code still come back anything else thatbo can do to fix that
ADP training, very good info there, also he has a range of books that are also good.
Got a 94 Chevy Silverado sets a code 43. Which is knock sensor any way to trick the knock sensor since I can't get it off to replace. Everything else has been worked on . I'm not going into everything, but you probably know. Thanks
If motor is pinging and knock sensors code is up could it be knock sensor
94 Fleetwood 350. The car runs like a dream, I get to half peddle and runs like a manual in 4th gear while driving 10mph. I replaced almost all the sensors, ignition, air and fuel line. No codes. Does my issue sound like auto ignition from carbon and bad knock sensors?
Great video
Thanks allot
Does my car have knock sensor
Opel Astra G 2000 1.2CC
Good morning. I'm working on a 2005 Honda Accord 2.4 that is not charging properly and yesterday someone told me that one of the components to check out it's the cam sensor . and make me think 🤔 what it cam sensor have to do to alternator not charging properly 😞
Question I have a nitrous fox went with Fitech and a wet plate 100 jet in it can I install a knock sensor to keep a watch on it when I spray ? Where would I install it
Gewiz mine cought my attention cause it's not screwed in all the way is it supposed to be showing some threads? Thanks for ALL this information😉
Does that means if I run my vehicle with better gas (89up) it would buy me time if I cannot change these sensors right away??
hi mr.brain my car is pathfineder 1997 model the problem is no power the puel pump spark plug not working
Thanks Brian, subscribed to Mandy's channel
I have a Toyota Sienna 2001. Where can I find a Knock sensor to buy online 🤔?
Can you use your airgun chisel LIGHTLEY to make the knock...???
Brian, are you sure the PCM is sending 5 Volts to a one wire Knock Sensor?
Yes Stefan the ECM supplies +5v, the reason may be the ECM operates better with the AC signal generated from the peizo element biased at a DC voltage, it may have something to do with a better signal to noise ratio. If you want to check for yourself, just turn the ignition on (engine not running) with the knock sensor disconnected and measure the voltage on the wire from the ECU. If you measure the voltage with the wire connected (again with ignition on and engine NOT running) the voltage will be lower due to the voltage drop across the internal 100k resistor inside the knock sensor which is connected to earth (thus completing the circuit).
Man I wish you could have shown an old wrist watch alarm piezo. It works basically in the opposite way. The speaker becomes the microphone. Only made for high frequency so must be something in the pre fire sound it's picking up that's high frequency?
hi I have a 03 single cab silverado with a check engine light on it because I need to replace knock sensor is it true if once I replace it, it will give me truck more power and save gas?
I wish I listened to you, just installed aftermarket knock sensors in my Silverado and less than a day later threw a p0327 code FML
Great video. Thanks for taking the time to make this. Very helpful.
Question: Does a P0325 error code indicate a faulty Knock Sensor? Or does it mean that the sensor is detecting knock on the block?
Wish you would changed one out back of the block some say you have to take out manifold to get to it are is there another way.w
brian. how bad can a knock sensor make a motor run. my 98 5.7 vortec has a constant misfire on 3 cylinders through all rpms. it runs so bad I can only go about 30 mph. new distributor cap and rotor, wires and plugs, new mpi spider assembly. had compression test on cylinders done, fuel pressure tests out. please any good info is appreciated
Tommy Jones make sure your injector plugs are plugged in and locked in. it can cause misfire of the plugs aren't in all the way. plus make sure your dist cap ate locked down tight. it's common fail among vortec v8s, I own two suburban. I know every nook and cranny about them.
does it cause bad engine proformance. My 2004 chevy 2500 6.0 seems like it drags and doesn't have the power it should. The knock sensors are showing up in the codes. Bank 1 and bank 2.
Darrell Norman those are common to fail, cuz water ingress in the sensors between the Valley. replace them and seal it with silicone. put everything back. you're good.
do you have any idea were a knock sensor is on a 1997 acura tl 3.2 is located on the motor
any info on sensor placement for instance intake valley versus externally connected to the lower block
Awesome. Thanks for showing us the cut away view👍
Hey Brian I had a question. When you said you ruled out the knock sensor on the 5.3 did you mean that it was the problem? Cause I'm having the exact issue on my 5.3 at 70mph that I'm currently trying to diagnose and only can get it to do it at that speed. And also I saw you at the Utah auto expo by the Nissan Titan diesel!!!
Thanks Brian, helpful for my boat.
My knock sensors are working it’s a new build on my s10 when I dropped a Engin I got it from a junkyard I never really tested it or did a compression check but I do hear a pinging sound and when I accelerate it backfires, I definitely hear a bad Lifter
2007 Toyota 4Runner they are inside the engine. I'm getting a code that says knock sensor. Do you think the average person should attempt this that has tools and some knowledge of what you definitely have a mechanic do it? For my vehicle it was like $1200.
Please respond thank you
I just replaced my knock sensor and siring harness on a 2003 Chevy 1500 5.3 when I replaced my intake manifold gasket. Got it all put back together and it runs alot better. Then I drove it for est. 100 miles and the check engine light came on. I read the code and it say knock sensor low voltage. Do you have any idea what causes this?
We did a knock sensors (AC Delco) on my 5.3L L33 engine and I still throwing codes for the knock sensors! My brother has been a great mechanic for easily 30 years and my truck is got us both scratching our heads! He's looked things up online on one of those main companies. I have low power (not able to power break - No burn out! ), getting 12 miles to gallon, we tried to bypass with to other sensors just to get it to pass inspection & no luck! And have you ever heard an hour meter reset itself? Because it has with mine. Maybe you can give me some ideas? Thanks for reading this.
@@kevinlonghurst631 I've not heard about any of the diesels hour meter resetting itself to zero like mine did!
If there's any GM mechanics out there that could check into that & give us some insight to what could be done to fix it or just simply what happened!??
It would be greatly appreciated! Thanks
Brian thanks so much for this video. Great stuff man!!! Question, I have a 1999 K1500 Suburban. Does it have 2 knock sensors? A friend of mine stated that it only has 1 and it's located underneath the engine...?
Thanks so much now I understand why truck ran bad after codes or set
Brian.....where are you located..........I got a check engine light that comes on and believe that the knock sensor is the problem.............2010 Cadillac SRX