False knock between shifts?

Kman11

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Update-

Did the crank relearn which got rid of the code.

Found that the mechanic who installed my suspension did not put the spring insulators on front spriings. I put those on, no change in knock retard.

So tonight I'm under the car and notice the rear end bump stops have different clearances. The driver side is basically touching the frame on level ground, the passenger has 3/4 of an inch or so clearance.

Same when measuring from the tire to fender. I have bmr lowering springs. I'm assuming this isn't normal? Maybe one spring sagged ?
 

03terminat0r

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Update-

Did the crank relearn which got rid of the code.

Found that the mechanic who installed my suspension did not put the spring insulators on front spriings. I put those on, no change in knock retard.

So tonight I'm under the car and notice the rear end bump stops have different clearances. The driver side is basically touching the frame on level ground, the passenger has 3/4 of an inch or so clearance.

Same when measuring from the tire to fender. I have bmr lowering springs. I'm assuming this isn't normal? Maybe one spring sagged ?

Any update? Did you ever get rid of the false knock?
 

Kman11

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Any update? Did you ever get rid of the false knock?

Unfortunately nope.

Really have no idea at this point.

I’ve found that if I ease into the throttle WOT, and shift slow and ease back in, it’s fine.

It’s something with the throttle stab that causes the knock. Even a part throttle stab cause a 10KR.

What makes it tough is it seems no ones knows how these sensors work. Lund is at a loss, says it’s gotta be something rubbing. I’ve read a lot of threads about “burst knock” on LS forums. It sounds like that to me, but Lund says no way.

I’m really close to buying another 11-14gt and swapping all my shit over, putting my current car back to stock and selling it.
 

basspro302

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Lots of people know how they work. Its a pizeo sensor that produces an a/c voltage when its vibrated. The ecm can be tuned to have a thresh hold for knock. So basically when they design the engine the will have all the known harmonics in place and they can see how the sensor is reacting to it and tune the pcm to only pick up real knock. That can go out the window with after markert parts changing the harmonics of the car.
 

basspro302

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Post a log or snap shot if you can

Does lund agree you have an issue?

Btw if you know some one that has a lab scope you can check the knock sensors to know 100% if theu are good or bad
 

stang910

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Unfortunately nope.

Really have no idea at this point.

I’ve found that if I ease into the throttle WOT, and shift slow and ease back in, it’s fine.

It’s something with the throttle stab that causes the knock. Even a part throttle stab cause a 10KR.

What makes it tough is it seems no ones knows how these sensors work. Lund is at a loss, says it’s gotta be something rubbing. I’ve read a lot of threads about “burst knock” on LS forums. It sounds like that to me, but Lund says no way.

I’m really close to buying another 11-14gt and swapping all my shit over, putting my current car back to stock and selling it.

I wouldn't get another car over this. You can always have the knock sensors desensitized or turned off. Are you spinning the tires when shifting gears? I've seen this pull timing.
 

Kman11

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Semi joking about ditching car. It's been frustrating though.

Here's the facts -
* I Installed new knock sensors
* checked exhaust 100 times
* checked Suspension etc

Knock retards when (+10kr)
* throttle tip in (flooring it) at 3k plus rpm
* sometimes will knock retard when down shifting to high rpm
* part throttle stabs while at mid to high rpm
* hard shift
* seen knock will taking off ramps that are declines will turning left., part throttle or no throttle.
* neutral rev shows knock ( usually 6kr or less)

Yes I get tire spin at lower speeds, but it also knocks at high speeds with no tire spin ( wot in 3rd, 4th, or hard shifts).

It DOES NOT knock when: (-4-5)
* I go wot slowly at any rpm
* I go wot at low rpm (2k) and stay wot to 7k.

Lund says no way it's a tune issue, must be something rubbing.

It's all about that initial throttle stab..

I'll do some fresh logs to show you all whats happening and post them
 
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wolfman311

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Semi joking about ditching car. It's been frustrating though.

Here's the facts -
* I Installed new knock sensors
* checked exhaust 100 times
* checked Suspension etc

Knock retards when (+10kr)
* throttle tip in (flooring it) at 3k plus rpm
* sometimes will knock retard when down shifting to high rpm
* part throttle stabs while at mid to high rpm
* hard shift
* seen knock will taking off ramps that are declines will turning left., part throttle or no throttle.
* neutral rev shows knock ( usually 6kr or less)

Yes I get tire spin at lower speeds, but it also knocks at high speeds with no tire spin ( wot in 3rd, 4th, or hard shifts).

It DOES NOT knock when: (-4-5)
* I go wot slowly at any rpm
* I go wot at low rpm (2k) and stay wot to 7k.

Lund says no way it's a tune issue, must be something rubbing.

It's all about that initial throttle stab..

I'll do some fresh logs to show you all whats happening and post them

Do you notice much oil in the throttle body? I assume you have some sort of catch can setup or breathers?
 

slow306stang

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I have the same issues as you with knock showing up. On the dyno it will not show any knock when starting a pull from 2500rpm.

On the street sometimes it will max out the KR at 10 degrees off of the initial hit and take a gear or two before it settles down.

D1, meth, full bmr suspension with spherical bushings, and a 3" cat back that i know it hits my anti roll bar. My meth pump has an aem controller and i often wonder if the knock is coming from the pump pulsing until it hits full volume.
 

basspro302

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Honestly i think you guys are over thinking it i get some knock stabing the throttle and stuff like that but overall i get no loss in power.
I mean if your beating on the car or doing crazy stuff youbwill see some knock.

Why dont you take a log send it to another tuner ask them how much to look at the log and tell yoy what they think.
 

Kman11

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I have the same issues as you with knock showing up. On the dyno it will not show any knock when starting a pull from 2500rpm.

On the street sometimes it will max out the KR at 10 degrees off of the initial hit and take a gear or two before it settles down.

D1, meth, full bmr suspension with spherical bushings, and a 3" cat back that i know it hits my anti roll bar. My meth pump has an aem controller and i often wonder if the knock is coming from the pump pulsing until it hits full volume.

We have similar setup and issue it sounds like.

I have an alky control kit. If it’s the meth pump, why would a part throttle stab cause it? I know my setup is designed to flow meth at 5psi boost, which shouldn’t be possible at part throttle.

I should test it with the meth kit off though.
 

Kman11

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Honestly i think you guys are over thinking it i get some knock stabing the throttle and stuff like that but overall i get no loss in power.
I mean if your beating on the car or doing crazy stuff youbwill see some knock.

Why dont you take a log send it to another tuner ask them how much to look at the log and tell yoy what they think.

When my car goes 10KR, instead of -4, the car is a dog.

If beating on a car is considered flooring it and shifting fast, somethings wrong.

If I didn’t have so many parts in this car I would have ditched it already. It’s completely taken the joy out of having it.

I have thought about talking to another tuner, but Lund seems to really know their shit. I can’t imagine they are missing something on their end.

Do many people turn off the knock sensors? I’d be open to this..
 

Kman11

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Here are some logs from last season when i was going back and forth with lund trying to figure it out. Lund got these files.

The KR is worse now then it was then, i'm seeing 10KR now, as opposed to 6KR in these files.
 

Attachments

  • 1st through 3rd knock on shifts.csv
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  • 4th gear no knock.csv
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  • part throttles knock.csv
    140.7 KB · Views: 152

Kman11

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Areas of interest are in yellow -

1st - 3rd, you will see knock come in on shifts.

Part throttle - you will see knock on part throttle

4th gear - Pull with -6 knock at end.
 

Kman11

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I spoke to Lund today, they reconfirmed no way it's a tuning issue, or burst knock.

What's the possibility it's related to the clutch? The clutch is the stock unit.. I noticed today while doing some test runs that leaving stop lights while letting the clutch out slowly there was KR.
 

w1tchblad3

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I spoke to Lund today, they reconfirmed no way it's a tuning issue, or burst knock.

What's the possibility it's related to the clutch? The clutch is the stock unit.. I noticed today while doing some test runs that leaving stop lights while letting the clutch out slowly there was KR.

I have been battling the exact same knock problems that you have described. I too have Lund tune my car is N/A on E-85 and auto. I have taken it to get checked out so many times over the last 9 months that now I have pretty much just given up. If you ever figure it out please post because I’ve had enough of this knock issues.
 

Kman11

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I have been battling the exact same knock problems that you have described. I too have Lund tune my car is N/A on E-85 and auto. I have taken it to get checked out so many times over the last 9 months that now I have pretty much just given up. If you ever figure it out please post because I’ve had enough of this knock issues.

Does yours show KR when revving ?

Stock driveshaft?
 

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