Knock sensor or dealer copout? - Page 3

1998ta__1991rs · 07-09-2011, 02:19 PM

pull the valve cover, it has to be somthing in the valvetrain then

bwelch · 07-09-2011, 02:29 PM

Time for a cam swap while your in there!

1 Slow Z · 07-09-2011, 02:47 PM

Quote:

Originally Posted by 1998ta__1991rs

pull the valve cover, it has to be somthing in the valvetrain then

x2, that is more than likely where the issue is.

98nbmz · 07-09-2011, 06:19 PM

Quote:

Originally Posted by PapaBear

Les Rogers has sold me 5 vehicles. Great guy. Used to live next door to my uncle Chris.

Yup, Chris always use to come fish out at my house. 25 cent on Bent pushrod

PapaBear · 07-09-2011, 06:47 PM

I told tech 20 times it was valve train. Whet do I know lol.

Derek · 07-09-2011, 10:19 PM

Quote:

Originally Posted by PapaBear

I'm not paying Jamie $375 to tune my truck, sorry. This will be figured out by the dealer. All I know about knock sensors after all this and all the reading I've done is that I don't know shit about them!

I didn't say jamie did I?

PapaBear · 07-10-2011, 08:11 AM

Quote:

Originally Posted by Derek

I didn't say jamie did I?

Nope and I didn't mean to either. JP rather. Sorry.

ElecTech · 07-10-2011, 08:51 AM

I don't wan't to get too deep into this, but the GM knock detection can determine which cylynder is knocking by first, considering which sensor is triggering (front/rear or in later years left/right). Then, it will use the current crank position and firing order to determine the offending cylinder. It also can control firing events on a cylinder by cylinder basis.

As far as misfires go, understand that the PCM does not detect a misfire, per se, it only detects rotational speed variations between predicted firing events. So any condition that causes a variation in rotational speed can be viewed as a "misfire" by the PCM. It doesn't have to be an actual lack of or incomplete combustion.

I'm in no way supporting the techs claims, just wanted to clarify a few things.

I hope you get it figured out soon. These situations can be very frustrating.

Good luck.

schardbody · 07-10-2011, 10:42 AM

jaime i agree, this is why my first suggestion was unplug the knock sensor harness, which would make the pcm pull timing automatically and see if there is any change (besides less power)..... if it still has the misfire then its not false knock produced by the headers and they need to look further.

if it were the headers causing false knock it wouldnt show as a single cylinder misfire..... so regardless its a cop out....

PapaBear · 07-11-2011, 05:35 AM

I just don't know what to do. Do I call them today and tell em i'm gonna come get the truck? Or do I let them figure it out?

So tired of thinking about this......

csikx · 07-11-2011, 06:37 AM

Why not try Crews Chevrolet and see what they say?

PapaBear · 07-11-2011, 06:40 AM

That's what I was thinking, but Hendrick gave me a rental car.....which on the way to work decided it was going to start going crazy and saying stability control is broken...>WTF.

I'm wondering, if I go back and demand my truck back, will they make me pay for the rental?

PapaBear · 07-11-2011, 05:12 PM

Need some advice guys.........

Service manager called me, and says that they can't figure out what's going on. He now wants money to change plugs/wires out to stock, and go from there. Not only that, he's asking if i'm gonna "help him out" with the work they've already done?

His specific quote "We can't find anything NON-OEM that could be causing this."

YET THEY STILL HAVEN"T PULLED THE VALVE COVER? WTF?

What am I supposed to do? Let them put plugs/wires on it? Problem is, clearance issues with LT headers and stock wires, #2 and #7 primaries will melt the wires. And they want to charge me?

HELP

LXtasy · 07-11-2011, 05:22 PM

Get some protective boots for the wires. The stock metal ones should work, or even any autoparts store sells them. Worth a shot.

PapaBear · 07-11-2011, 05:27 PM

There are heat socks on the PCMforless wires now. I just called em back and said to put plugs/wires on it with my socks. If it doesn't fix it, I told him I wanted it returned to the way it was and for them to figure out what's going on.

bwelch · 07-11-2011, 06:42 PM

Thats not the problem if you switch the wires around and changed the plug already and it stayed the same. They aren't gonna figure it out. If they really wanted to figure it out it would be fixed by now and you wouldn't be driving that pos HHR. The problem is on one cyclinder but they want to put stock shit on all of the cyclinder and then they are gonna @ss rape you on the price of plugs, wires, and install. The problem with most dealerships is that some of the techs dont know shit about diagnosing a problem they just throw parts at it until they get lucky. Take it to somebody who knows what they are doing and pay them to diagnose the problem. It will cost the same as the stock plugs, wires, and there labor. talk to Gerald maybe he can figure it out.

red99pony · 07-11-2011, 06:52 PM

yea i say Gerald too. he found some strange shit on my mustang. depends on if he is up to the challenge, or has the free time.

minytrker · 07-11-2011, 06:52 PM

Quote:

Originally Posted by PapaBear

There are heat socks on the PCMforless wires now. I just called em back and said to put plugs/wires on it with my socks. If it doesn't fix it, I told him I wanted it returned to the way it was and for them to figure out what's going on.

What exactly did you change when the miss fire started?

I did work (tuning) for several of the dealers in Charleston/North Charleston when I had my shop in North Charleston. After being the dealers and dealing with there tech's I lost faith in there mechanical skill's.

PapaBear · 07-11-2011, 07:12 PM

Well, all of this started after Gerald had my truck for a week or so. He did trans build,longtubes with catless y pipe and plugs and wires.

About 600 miles later this started. I never really got on it hard during the first 4-500 miles, but a week before I noticed this issue, I hammered it a couple of times on the interstate fucking up a dodge neon and never had one issue.

I'm at a loss. I really really hope that stock plugs and wires DOESN'T fix it, cuz if they do I gotta pay for them and eat my words.

PapaBear · 07-11-2011, 07:13 PM

Oh and service manager had the followin to say about the tech: "he's one of my top guys, and surely the most experienced with MODIFIED vehicles."

Intake and exhaust is modified now? WTF? I put intake and exhaust on my 07 silvy a week after it rolled off the lot? Everybody does!

07-09-2011, 02:19 PM	#41
1998ta__1991rs Senior Member Join Date: Jun 2008 Location: West Ash Posts: 4,283	pull the valve cover, it has to be somthing in the valvetrain then __________________ Funny

07-09-2011, 02:29 PM	#42
bwelch Senior Member Join Date: Aug 2009 Posts: 3,774	Time for a cam swap while your in there! __________________

07-10-2011, 08:51 AM	#48
ElecTech Senior Member Join Date: May 2009 Location: Charleston, SC Posts: 1,489	I don't wan't to get too deep into this, but the GM knock detection can determine which cylynder is knocking by first, considering which sensor is triggering (front/rear or in later years left/right). Then, it will use the current crank position and firing order to determine the offending cylinder. It also can control firing events on a cylinder by cylinder basis. As far as misfires go, understand that the PCM does not detect a misfire, per se, it only detects rotational speed variations between predicted firing events. So any condition that causes a variation in rotational speed can be viewed as a "misfire" by the PCM. It doesn't have to be an actual lack of or incomplete combustion. I'm in no way supporting the techs claims, just wanted to clarify a few things. I hope you get it figured out soon. These situations can be very frustrating. Good luck. __________________ Jaime

07-11-2011, 05:12 PM	#53
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	Need some advice guys......... Service manager called me, and says that they can't figure out what's going on. He now wants money to change plugs/wires out to stock, and go from there. Not only that, he's asking if i'm gonna "help him out" with the work they've already done? His specific quote "We can't find anything NON-OEM that could be causing this." YET THEY STILL HAVEN"T PULLED THE VALVE COVER? WTF? What am I supposed to do? Let them put plugs/wires on it? Problem is, clearance issues with LT headers and stock wires, #2 and #7 primaries will melt the wires. And they want to charge me? HELP Last edited by PapaBear; 07-22-2011 at 12:26 PM.

07-11-2011, 05:22 PM	#54
LXtasy Senior Member Join Date: Dec 2006 Location: Summerville, SC Posts: 9,564	Get some protective boots for the wires. The stock metal ones should work, or even any autoparts store sells them. Worth a shot. __________________

07-09-2011, 06:47 PM	#45
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	I told tech 20 times it was valve train. Whet do I know lol.

07-10-2011, 10:42 AM	#49
schardbody Senior Member Join Date: Sep 2008 Posts: 1,158	jaime i agree, this is why my first suggestion was unplug the knock sensor harness, which would make the pcm pull timing automatically and see if there is any change (besides less power)..... if it still has the misfire then its not false knock produced by the headers and they need to look further. if it were the headers causing false knock it wouldnt show as a single cylinder misfire..... so regardless its a cop out....

07-11-2011, 05:35 AM	#50
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	I just don't know what to do. Do I call them today and tell em i'm gonna come get the truck? Or do I let them figure it out? So tired of thinking about this......

07-11-2011, 06:37 AM	#51
csikx Senior Member Join Date: Feb 2011 Posts: 1,398	Why not try Crews Chevrolet and see what they say?

07-11-2011, 06:40 AM	#52
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	That's what I was thinking, but Hendrick gave me a rental car.....which on the way to work decided it was going to start going crazy and saying stability control is broken...>WTF. I'm wondering, if I go back and demand my truck back, will they make me pay for the rental?

07-11-2011, 05:27 PM	#55
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	There are heat socks on the PCMforless wires now. I just called em back and said to put plugs/wires on it with my socks. If it doesn't fix it, I told him I wanted it returned to the way it was and for them to figure out what's going on.

07-11-2011, 06:42 PM	#56
bwelch Senior Member Join Date: Aug 2009 Posts: 3,774	Thats not the problem if you switch the wires around and changed the plug already and it stayed the same. They aren't gonna figure it out. If they really wanted to figure it out it would be fixed by now and you wouldn't be driving that pos HHR. The problem is on one cyclinder but they want to put stock shit on all of the cyclinder and then they are gonna @ss rape you on the price of plugs, wires, and install. The problem with most dealerships is that some of the techs dont know shit about diagnosing a problem they just throw parts at it until they get lucky. Take it to somebody who knows what they are doing and pay them to diagnose the problem. It will cost the same as the stock plugs, wires, and there labor. talk to Gerald maybe he can figure it out. __________________ Last edited by bwelch; 07-11-2011 at 09:03 PM.

07-11-2011, 06:52 PM	#57
red99pony Senior Member Join Date: Jul 2009 Location: goose creek sc Posts: 818	yea i say Gerald too. he found some strange shit on my mustang. depends on if he is up to the challenge, or has the free time. __________________ 02 lightning all stock 99 mustang gt Tork Tech terminator kit making a little boost

07-11-2011, 07:12 PM	#59
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	Well, all of this started after Gerald had my truck for a week or so. He did trans build,longtubes with catless y pipe and plugs and wires. About 600 miles later this started. I never really got on it hard during the first 4-500 miles, but a week before I noticed this issue, I hammered it a couple of times on the interstate fucking up a dodge neon and never had one issue. I'm at a loss. I really really hope that stock plugs and wires DOESN'T fix it, cuz if they do I gotta pay for them and eat my words. Last edited by PapaBear; 07-22-2011 at 12:26 PM.

07-11-2011, 07:13 PM	#60
PapaBear Senior Member Join Date: Aug 2010 Posts: 2,809	Oh and service manager had the followin to say about the tech: "he's one of my top guys, and surely the most experienced with MODIFIED vehicles." Intake and exhaust is modified now? WTF? I put intake and exhaust on my 07 silvy a week after it rolled off the lot? Everybody does!

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