Knock sensor help

[olegk]

I have a 2003 hummer h2, with 50,000 miles on it. I was driving down the highway a last week, and my check engine light came on. I have been offroading and going through water the day before so i figured it had something to do with that.
i took the Hummer a GM certified repair shop and they said the light had to do with the Knock sensor. This will cost around $500 to replace. i declined replacing it and decided to do some research on it. the car runs fine, but i noticed when i floor it of a stop, the engine lags bigtime.
my question is: Is it nesessary to replace the knock sensor, and is there going to be any damage to my car if i dont? and also how hard would it be to do it my self? (i have decent mechanic skills), the technicians said the job requires that the intake manifold be taken off. Is it worth risking doing it yourself or is it better to play it safe and let the professionals do it?

[TxFireman]

Wrong forum.. LOL

The knock sensor adjusts the timing when detonation occurs etc. So it constantly monitors the timing, and adjusts as needed. I have no idea of it's location on the H3's 5 cylinder. I know where it's located on a older small block GM V8, and it's easy enough to change out on one of those... if it's not being stubborn and hard to turn.

They used to put the sensor on the lower half of the block near the freeze plugs. Under the intake sounds like a real PIA place to put it.

[PARAGON]

Originally Posted by TxFireman

Wrong forum.. LOL

The knock sensor adjusts the timing when detonation occurs etc. So it constantly monitors the timing, and adjusts as needed. I have no idea of it's location on the H3's 5 cylinder. I know where it's located on a older small block GM V8, and it's easy enough to change out on one of those... if it's not being stubborn and hard to turn.

They used to put the sensor on the lower half of the block near the freeze plugs. Under the intake sounds like a real PIA place to put it.

Did you inhale too much toxic fumes?

He said a 2003 hummer h2 with 50,000 miles..... not an H3. It's in the right forum.

Yes the KS is located underneath the intake and the intake would have to be removed, I think there are 2 of them on the 6.0L and if you are doing one, you might as well go ahead and do both.

Really not much reason why anyone slightly mechanically inclined couldn't do the job.

[TxFireman]

Originally Posted by PARAGON

Did you inhale too much toxic fumes?

He said a 2003 hummer h2 with 50,000 miles..... not an H3. It's in the right forum.

Yes the KS is located underneath the intake and the intake would have to be removed, I think there are 2 of them on the 6.0L and if you are doing one, you might as well go ahead and do both.

Really not much reason why anyone slightly mechanically inclined couldn't do the job.

I meant that I was in the wrong forum, when I answered. Nice amount of respect there, that you have for the people who make it their duty to serve the public. Do you go around kicking wounded verterans because their wheelchairs get in your way? Give your parents props, the next time you see them, they've raised a first class asshat.

What a ****tard ...

[H2 Doberman]

How in the hell were we suppose to know that you were an H3 guy.

Paragon responded according to how the post read. You never said that YOU were in the wrong forum.

[md_sailor]

I had a similar problem about a year ago, the dealer ended up replacing the Catalytic Converter under warranty... no problems since then. You stated that it was a GM certified shop? Was it a Dealer? Did they diagnose your problem with a Tech 2? if not I would find a technician who has one and get the codes read by someone who knows exactly what to look for. just my .02c worth Good Luck!

[PARAGON]

Originally Posted by TxFireman

I meant that I was in the wrong forum, when I answered. Nice amount of respect there, that you have for the people who make it their duty to serve the public. Do you go around kicking wounded verterans because their wheelchairs get in your way? Give your parents props, the next time you see them, they've raised a first class asshat.

What a ****tard ...

Give me a fvcking break!

Is it now everyone is going to use some excuse such as their job as a crutch? You're on the public payroll..... so what? What does that have to do with the price of eggs in Zimbabwe? Next thing you know some yokel will be crutching up on the fact that he is a public servant ditch digger.

I have no respect for you, because I don't know you and you have yet to earn my respect. The fact that you are here under the banner of your job was easy enough pickings for me to poke fun. You don't like it? Stay in the thin-skinned H3 section.

[timgco]

I thought "real fireman" had thicker skin than that. I bet he doens't even "fight fires." I bet he cleans the station house and does all the cooking only. THere's really no shame in beinig the station beotch though.

Gawd, what a $i$$y.

[TxFireman]

Originally Posted by PARAGON

Give me a fvcking break!

Is it now everyone is going to use some excuse such as their job as a crutch? You're on the public payroll..... so what? What does that have to do with the price of eggs in Zimbabwe? Next thing you know some yokel will be crutching up on the fact that he is a public servant ditch digger.

I have no respect for you, because I don't know you and you have yet to earn my respect. The fact that you are here under the banner of your job was easy enough pickings for me to poke fun. You don't like it? Stay in the thin-skinned H3 section.

Seeing as how many first responders in NYC are suffering the ill effects of toxic gases and who knows what all else, at TWC , after 9/11, I find your "poking fun" at my "job title" tasteless. It's that simple. You're a sack of ****, by your own admission. Perhaps you think it's funny that many of them are sick or dieing as a result of their exposures? At least enough to use it as "humor". Sorry, but I don't find it funny, and I would venture to say that many others don't either.

Now, I won't carry on the hi-jack to this thread any longer, out of respect for the member posting the question.

[H2 Doberman]

WTF!!!

What does any of that have to do with posting in this forum

[PARAGON]

Originally Posted by TxFireman

Seeing as how many first responders in NYC are suffering the ill effects of toxic gases and who knows what all else, at TWC , after 9/11, I find your "poking fun" at my "job title" tasteless. It's that simple. You're a sack of ****, by your own admission. Perhaps you think it's funny that many of them are sick or dieing as a result of their exposures? At least enough to use it as "humor". Sorry, but I don't find it funny, and I would venture to say that many others don't either.

Now, I won't carry on the hi-jack to this thread any longer, out of respect for the member posting the question.

you're ghey, aren't you?

[KenP]

Originally Posted by TxFireman

I meant that I was in the wrong forum, when I answered. Nice amount of respect there, that you have for the people who make it their duty to serve the public. Do you go around kicking wounded verterans because their wheelchairs get in your way? Give your parents props, the next time you see them, they've raised a first class asshat.

What a ****tard ...

Are you kidding me? You should be ashamed of yourself trying to use your occupation as a crutch on a TRUCK forum.

Seriously, you should be embarrassed. Don't show this to your wife or coworkers...

Pityful. Truely pitiful.

As for the knock sensor, if you've never torn down the top of a modern FI computer controlled engine, take it to someone qualified. You sound apprehensive so save yourself the aggrivation. But I bet you could do it given time and patients.

Have them break down the labor vs parts costs, then you may be able to save some money getting the parts online.

[DRTYFN]

Originally Posted by TxFireman

I meant that I was in the wrong forum, when I answered. Nice amount of respect there, that you have for the people who make it their duty to serve the public. Do you go around kicking wounded verterans because their wheelchairs get in your way? Give your parents props, the next time you see them, they've raised a first class asshat.

What a ****tard ...

No, you're the tard. How pathetic of you to attempt to use your job as a shield. Weak.

[CO Hummer]

Originally Posted by TxFireman

Seeing as how many first responders in NYC are suffering the ill effects of toxic gases and who knows what all else, at TWC , after 9/11, I find your "poking fun" at my "job title" tasteless. It's that simple. You're a sack of ****, by your own admission. Perhaps you think it's funny that many of them are sick or dieing as a result of their exposures? At least enough to use it as "humor". Sorry, but I don't find it funny, and I would venture to say that many others don't either.

Now, I won't carry on the hi-jack to this thread any longer, out of respect for the member posting the question.

Hey Tx, I apologize for these guys. They weren't thinking that about the fact that you volunteer all your services for free and that you are doing your job simply out of the goodness of your heart.

Give me break, you moron.

[DennisAJC]

I'm confused.

TxFireman is a prostitute?

[ROX]

Originally Posted by TxFireman

Wrong forum.. LOL

I am a pussy.

No need to brag about it.

[f5fstop]

Originally Posted by TxFireman

Wrong forum.. LOL

The knock sensor adjusts the timing when detonation occurs etc. So it constantly monitors the timing, and adjusts as needed. I have no idea of it's location on the H3's 5 cylinder. I know where it's located on a older small block GM V8, and it's easy enough to change out on one of those... if it's not being stubborn and hard to turn.

They used to put the sensor on the lower half of the block near the freeze plugs. Under the intake sounds like a real PIA place to put it.

Actually, a knock sensor does not monitor the timing and it certainly cannot adjust the timing as required.
The knock sensor detects frequencies, and outputs a voltage signal to the PCM based up on the frequency detected. The PCM monitors the frequency output of the knock sensor and when a specific frequency range is detected it will adjust engine timing to reduce the knock. Most of the modern PCM's actually learn the engine since all engine output noise.

As for how to change, Paragon explained that quite well.