Knock Ping Sensor

Z71Silverado · November 27, 2009

Hey. I brought my truck to my mechanic because the engine light was on. he replaced some type valve flap thing that was on the gas tank. anyways, the engine light is still coming on. he said another code came up but to wait and see if it came back on. he said it was a engine knock ping sensor. He said it was up in the engine behind the exhaust manifold.

My question here is. has anyone had this problem? he mentioned something about bad gas. he asked if i had put any bad gas in the truck. i told him that i was not sure if i put bad gas in the tank. i fill my truck up at the local store once a week. am i losing any performance or MPG with this sensor being messed up? i live in new york and don't need an inspection for another 8 months. i was planning on leaving it be until then. it seems like there will be a lot of labor to do this and don't want to spend the money as this time. any info is greatly appreciated. thanks.

flytuc · November 27, 2009

Hey,

I got this code along with some O2's going bad when driving through some water..I got the O2's replaced and cleared the code manually and it Knock Sensor) came back after a few days of driving..the engine is not knocking, shaking anymore, but still get the light..I have now been driving for about 4 months with it like this and nothing has happened..

the knock sensor is located under the "intake" manifold..I have read this forum and wanted to try and fix this, but I dont wanna screw up my daily driver..I too have often wondered am I getting poor gas mileage due to this..I dunno..Anyway, just thought you would like to know your not the only one out there..

Stephen

Yotaman · November 27, 2009

I had the knock sensors replaced in my 01 Silverado 4.8 From what I understand the sensors ( there are two ) are prone to having water build up around them and corroding the the sensor. People who wash there engines are more likely to see a problem sooner. The entire intake has to come off and the area where the sensors go should be cleaned and then a silicone dike around the spot where the probe goes. I had mine done a a local mechanic shop for 400.00 or so dollars. I was afraid to pull the intake. You may as well replace both while in there.

Good Luck.

Yotaman

ryan_hermanutz · November 27, 2009

Hey. I brought my truck to my mechanic because the engine light was on. he replaced some type valve flap thing that was on the gas tank. anyways, the engine light is still coming on. he said another code came up but to wait and see if it came back on. he said it was a engine knock ping sensor. He said it was up in the engine behind the exhaust manifold.

My question here is. has anyone had this problem? he mentioned something about bad gas. he asked if i had put any bad gas in the truck. i told him that i was not sure if i put bad gas in the tank. i fill my truck up at the local store once a week. am i losing any performance or MPG with this sensor being messed up? i live in new york and don't need an inspection for another 8 months. i was planning on leaving it be until then. it seems like there will be a lot of labor to do this and don't want to spend the money as this time. any info is greatly appreciated. thanks.

Would you walk around with a broken foot for 8 months? Just take it in and have it fixed so your 1 problem doesn't turn into 3 or 4.

jtupper · November 27, 2009

Overall, it's not too difficult to do. You will want to replace both or you might be doing it again before long. I would also replace the knock sensor wiring harness as well. You will need two sensors, the wiring harness and an intake manifold gasket. You might also consider replacing the injector o-rings while you have the fuel rails out, although I didn't do that.

http://www.gm-trucks.com/forums/index.php?showtopic=102790

http://www.gm-trucks.com/forums/index.php?showtopic=86039

Ryan00TJ · November 27, 2009

I agree it's not that hard of job for a mechanically inclined person with most basic hand tools. It's also made easier working on a truck engine that makes most things accessible. My LS1 in my SS was half tucked in under the cowl and doing anything was 2x as hard. I believe on the LS2 engines and newer GM truck engines the KS were moved to the side of the block instead of the lifter valley as they can sense knock frequency from there better.

Z71Silverado · November 28, 2009

i don't know anything about rebuilding an entire engine but i did use to work for an auto shop. we did minor services and such. do you think i could do this myself or would it be better off for my mechanic to do it?

Z71Silverado · November 28, 2009

bump

txab · November 28, 2009

You know your mechanical skills better than we do. After looking over the threads showing the process to R&R the sensors, you should have a feel whether you can tackle it yourself. It's not complicated, just takes time. Mechanical thinking ability and skills are very helpful. Why not grab you a service manual to help guide you through?

Z71Silverado · November 28, 2009

You know your mechanical skills better than we do. After looking over the threads showing the process to R&R the sensors, you should have a feel whether you can tackle it yourself. It's not complicated, just takes time. Mechanical thinking ability and skills are very helpful. Why not grab you a service manual to help guide you through?

i think i will. my mechanic is my dad's best friend. his shop is always busy. i'm going to try and do this myself.

txab · November 28, 2009

i think i will. my mechanic is my dad's best friend. his shop is always busy. i'm going to try and do this myself.

Great. You can always ask him if you run into a snag. I think you'll find it's no big deal

desrtrat · November 28, 2009

how old is your truck, and how many miles?? if your under 5 yrs/1000,00 miles. cover it under warranty. i would not wait long to get them replaced. you may not hear any knocking/pinging that's the ones that could cost you a motor.

good luck

05Z71ss · November 30, 2009

I just did mine (05 z71) and it is not hard to do at all. IN a nut shell all u do is unplug all the injectors, Tb sensor, the emission sensor on top the intake, Unscrew the 10 bolts and the intake comes right off. JUst buy two knock sensors, wire harness, and some RVT silicon. Build a dam around both of them after you change them. I also took out the two foam pieces, I think they trap more stuff than keep out. This is about 3 hour job, including take couple breaks.

OH yeah dont forget after u put everything back together, to check your injectors and make sure they snap back in. HAHA