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
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
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.
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!
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.
I just replace the knock sensors and I think I use bbw and the engine check light is still on thanks to you I will buy the ac delco and hopefully that will fix my truck
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.
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!
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 👍
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.
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...
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.
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.
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 .
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?
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.
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
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
I'm amazed at how ignorant alot of mechanics are about knock sensors.when you get a code for knock sensor it doesn't mean the sensor is bad it means it's sensing an engine problem like a bad injector for example.whatever the engine problem,fix the problem and it will also eliminate the knock code.knock sensors rarely go bad.
Boots789 V what is the best remedy (should I just run premium fuel ⛽️ or should I use sea foam) 1997 Cadillac calls for 91 octane. FYI just bought it but it has knock sensor code. It sat for a year and I just replaced the fuel pump and started it for the first time. Please reply
I think it's "pick on Sunday" for you, Brian. Your video was very good but some of your terminology is wrong. It's pre-ignition and detonation, not pre-detonation. Detonation is when two flame fronts collide and cause a spark knock (Ping) and is what the knock sensor detects. Pre-ignition is when parts of the combustion chamber, carbon etc. fire the mixture before the spark does. This causes pistons and other parts to melt and can cause detonation to occur. Recently had a Hyundai Accent emission failure from another shop with a knock sensor code and after replacing the knock sensor twice and spending lots of the women's money on the car, I found it was only low on oil. Knock sensor was detecting the valve train noise as a knock. Added oil to full level, problem solved.
wysetech2000 I misspoke pretty hard on this video. I look like death warmed over, and I felt that way here too. Great work on the woman's car. I bet she really appreciated that!
briansmobile1 I hear you man! I'm finally pulling down decent flag hours. It's great that I'm faster, but I still did more work so I'm sore. I never thought I'd be an Automotive Tech. Finding your video started me on my happy path. I'm glad I learned so much. Great video. As far as mixed up terms go. We all do it, but I never misunderstood your points over it. My second "but" is thanks for being brave and putting it on camera. Most of us don't have it recorded. :)
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).
And the ECU expects to hear something on Toyotas. So you can't just shunt or bypass them. It isn't resistors, but a 8000 picofarad capacitor(pf), aka .008 microfarad (uf) capacitor. I just want to tell the ecu everything is fine. It's just a noisy waterpump and ignore it. But no, their firmware listens to the engine in the ECU.. Time to hack the firmware or make a signal generator based on rpms to deliver the right return to the ECU. 1995 Camry V6 so that covers the 1992-2001 models.
HI Brian my daughter has a 09 accent. Show the P0328. So I replace her knock sensor. The car ran fine for 2 months, And now it shows the code again!! Watching your video I heard you say to buy the factory Knock sensor actually I bought it at napa And they said it was OEM factory ... could this be the issue? Her car runs fine and no misfiring!. Thanks Brian take care 👍🏼👍🏼
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 ?
are you sure the computer feeds the knock sensor 5v? @11:09 also, you said that the signal voltage comes back on the same wire? ac power would be a wave form at what ever hz, i know you can run split and 3phase ac on the same wires, but never heard of dc and ac being used on the same wire. fyi: i likely misunderstood you, other wise i need to rethink what i thought i knew about electricity.great video btw, i have been watching your stuff off and on for years as you are one of the few who insist on understanding theory and application before moving on or trying to explain something.
Excellent info here Would a knock sensor create random engine light comes on steady and then studder like pressing on and off gas pedal when im not... maybe 10 miles into driving. This is intermittent. If i turn off car for 5 minutes or 5 hours it starts again in 10 miles..not every time 😮😮 and yesssss ill watch your other videos and also check out the recommended channels Thank you 😊
man this guy is one smart cookie. if it wasnt for the fact that im nearly 30 id have to say when i grow up i wanna be just like him lmao. seriously tho my pisspoor wikipedia search on knock sensor wont hold a candle to this.
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.
Chevy knock sensors are cancer. I decided it wasn't worth it to replace it on my 04 avalanche and just spliced that shit (bank 2 failed, so I spliced both into bank 1). If bank 1 ever fails, I'll probably just wire in a resistor bypass. Trucks 17 years old and has 185k miles on it. It has served its purpose. If it burns up a piston from daily driving knock i'll just slap another 5.3 in there or junk it and get another vehicle.
Hi ,I am from Iraq and I have little English not like you,I think this video,for all countries, most of countries have little English,will you please explain using more best English languages,thank you very much,
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
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....?
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 !!!!
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
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?
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.
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 😞
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.
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?
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.
There's a french guy in the USA with a gurgling accent. Never heard one like it BUT HE tests the 2 wire type WITH A WRENCH. It's only a cheap hyundai with the crap theta 2 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
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
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?
I need help , I have a p0332 and a p0327 code that just will not go away , I have tested and tested and changed and changed , I tested both sensors , both have 101 ohms , and when I use ac current testing them with a hammer to the block , the volts go from 3 up to 5 or 7 on both of them ,so I'm assuming both my sensors are working , and yes I used acdeco sensors the second time I did , but didn't help , I checked the volts coming from pcm and it was from 2.5 to 2.8 , then I checked the resistance on the harness going to the pcm also , it read 0 , not open circuit , so pleassssssseeeeee help me what else can I do ?
I H8 all these videod that do NOT tell you year, make, engine. My 2008 chevy 1500 express V6 has me looking at videos BUT because the MOST necessary info is not given so INSTEAD i find myself chasing my tail... THANKS FOR NOTHING
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.
Had the P0330 code pop yesterday on a Toyota 3.0. Take everything off on top of engine routine....Bad harness? probably due to location. sensors $100 each and car requires 2. Wish me 4 hours of luck.
"Don't use aftermarket sensors on a Chevy." Too late, already did. 2 weeks later I'm getting the same CEL again, have to buy new OE sensors, and pull the intake manifold again. I knew better, but tried it anyway. I'm also getting p0327, oh well, not an overly difficult job.
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.
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
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...?
