5-6 degree knock on stock tune

[usgiorgi]

Hi guys, yesterday I finally decided to add a few knock PIDs into my sct x4 to monitor the car. I'm on stock tune and always use either Shell or Sunoco 93 gas. The global knock sometimes dips to -2 but mostly it goes positive 2-6 throughout the RPM range. I need to add timing PID as well to see how much it's actually pulling.

I read online that sometimes stock tune has alot of knock for various reasons. I want to get to the bottom of it. I also see that there's tons of threads with false knocks from the exhaust components.

Anyone have any suggestions on where to start looking for the problem?

:cheers:

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[ahl395]

Do you see the knock at WOT? or just cruising?

I saw some knock on my stock car when cruising or light accel, but it came and went away briefly. If you're seeing it often at part throttle, it may be false knock (usually from something exhaust related). If its knocking at WOT I think there's a bigger problem.

 

[Gibbo205]

My car has the same issue, it was not showing so much on the Lund tune, but now I am on AED it shows more.

Shaun at AED says some tuners de-sensitise the sensors whereas he does not unless running E85 or race gas. Stock Ford map is not de-sensitised either, so could be your issue. Getting positive knock should not happen on stock Ford map or tuned with good gas, so you need to cure it as it is robbing you a lot of power, like I say may car makes 31-32 degrees WOT, but when the knock sensor goes off it sits at +5.99 and my timing is 18-20 degrees, so when this happens I am probably losing around 30-50WHP.

My car will sit at -4.00 on a WOT pull in any gear, but if I go WOT through gears it sits at +5.99

I can even cause it to knock by revving hard in neutral.

When it knocks timing is sub 20 degrees, whereas the car normally makes 31-32 degrees timing WOT, even tried a full bottle of torco which had no impact.

Shaun assures me it is not the tune and I 100% believe him, he says the car is knocking somewhere, like exhaust, block plate etc.

So I started checking over my car and low and behold the right hand side cat seems to have failed and as such the exhaust sounds like it is full of metal shrapnel which when changing gear or hitting the gas pedal hard causes enough resonance for knock sensors to pick up. Well that is our thought anyway.

Ford are replacing the cat under warranty next week, so fingers crossed that cures it, in the meantime I am going to try switching maf sensors as I have a spare one from my 350 CAI to rule out maf sensor being fouled.

 

[usgiorgi]

Do you see the knock at WOT? or just cruising?

I saw some knock on my stock car when cruising or light accel, but it came and went away briefly. If you're seeing it often at part throttle, it may be false knock (usually from something exhaust related). If its knocking at WOT I think there's a bigger problem.

Pretty much anytime I touch the throttle there's some knock. It seems to increase throughout the RPMs.

 

[Tommy V]

My car has the same issue, it was not showing so much on the Lund tune, but now I am on AED it shows more.

Shaun at AED says some tuners de-sensitise the sensors whereas he does not unless running E85 or race gas. Stock Ford map is not de-sensitised either, so could be your issue. Getting positive knock should not happen on stock Ford map or tuned with good gas, so you need to cure it as it is robbing you a lot of power, like I say may car makes 31-32 degrees WOT, but when the knock sensor goes off it sits at +5.99 and my timing is 18-20 degrees, so when this happens I am probably losing around 30-50WHP.

My car will sit at -4.00 on a WOT pull in any gear, but if I go WOT through gears it sits at +5.99

I can even cause it to knock by revving hard in neutral.

When it knocks timing is sub 20 degrees, whereas the car normally makes 31-32 degrees timing WOT, even tried a full bottle of torco which had no impact.

Shaun assures me it is not the tune and I 100% believe him, he says the car is knocking somewhere, like exhaust, block plate etc.

So I started checking over my car and low and behold the right hand side cat seems to have failed and as such the exhaust sounds like it is full of metal shrapnel which when changing gear or hitting the gas pedal hard causes enough resonance for knock sensors to pick up. Well that is our thought anyway.

Ford are replacing the cat under warranty next week, so fingers crossed that cures it, in the meantime I am going to try switching maf sensors as I have a spare one from my 350 CAI to rule out maf sensor being fouled.

If it was the maf u would be able to see it in the logs,especially if your going from -4 to +5.99 knock.Pull up just the maf and wheir your getting the positive knock and see if anything stands out with the maf sensor.

 

[Gibbo205]

If it was the maf u would be able to see it in the logs,especially if your going from -4 to +5.99 knock.Pull up just the maf and wheir your getting the positive knock and see if anything stands out with the maf sensor.

True and Shaun would of probably said, he said the logs look superb, fuelling is spot on, solid 31-32 degrees timing.

He said its 100% false knock, not tune related.

I was merely going to try the maf just to rule things out as I have one spare and its like a two minute job to swap them out.

 

[sloppymax]

Pretty much anytime I touch the throttle there's some knock. It seems to increase throughout the RPMs.

Stock exhaust? If so or even with an aftermarket catback, check the clamp closest to the driver door. If you do not see any marks from the exhaust hitting the body then take a rubber mallet and hit the exhaust in various places. I assume you do not have headers since you have a stock tune.

 

[usgiorgi]

Stock exhaust? If so or even with an aftermarket catback, check the clamp closest to the driver door. If you do not see any marks from the exhaust hitting the body then take a rubber mallet and hit the exhaust in various places. I assume you do not have headers since you have a stock tune.

Nope it's an aftermarket catback and no headers. Gonna start going Jeremy Clarkson on the car!

 

[sloppymax]

Most aftermarket catbacks reuse that same clamp. If you had someone install it, they might have angled it too high and the end of the threads is resting on or right at the body. I did the same thing when I installed a catback on my old 2012 GT. Looks for scratches as they will tell the story.

 

[usgiorgi]

Most aftermarket catbacks reuse that same clamp. If you had someone install it, they might have angled it too high and the end of the threads is resting on or right at the body. I did the same thing when I installed a catback on my old 2012 GT. Looks for scratches as they will tell the story.

Yea the people who installed it weren't the most competent either, so that's the first place I'm gonna check

 

[BmacIL]

Interesting. Highest I've seen is +0.7 on my Livernois tune on several logs. It's negative or 0 99.99% of the time.

 

[usgiorgi]

Interesting. Highest I've seen is +0.7 on my Livernois tune on several logs. It's negative or 0 99.99% of the time.

I'm honestly getting really annoyed with the car. I've had it for 13 months and its already had a new intake manifold put in, new trunk (still hits bumper and tail light so it's going back to the dealer) the AC feels like it's gonna die any day now and the knock is just about the final straw. I was about to contact Lund for a tune, but if it's knocking on a stock tune and it turns out to not be false knock, it's gonna be traded in for another car. :frusty:

 

[SolarFlare]

True and Shaun would of probably said, he said the logs look superb, fuelling is spot on, solid 31-32 degrees timing.

He said its 100% false knock, not tune related.

I was merely going to try the maf just to rule things out as I have one spare and its like a two minute job to swap them out.

How are you seeing 31* of timing on the log with +6 on the KR? So he's commanding 37*?? 31* of timing on 93oct is way too much on 93.

 

[blueylewis]

I'm honestly getting really annoyed with the car. I've had it for 13 months and its already had a new intake manifold put in, new trunk (still hits bumper and tail light so it's going back to the dealer) the AC feels like it's gonna die any day now and the knock is just about the final straw. I was about to contact Lund for a tune, but if it's knocking on a stock tune and it turns out to not be false knock, it's gonna be traded in for another car. :frusty:

I feel your pain, I have a knock too and now ford has my engine apart. My knock was very audible while driving under slight throttle application. :doh:

 

[Gibbo205]

How are you seeing 31* of timing on the log with +6 on the KR? So he's commanding 37*?? 31* of timing on 93oct is way too much on 93.

No re-read my post.

If I roll into the throttle say in 3rd gear, I get no knock and it builds to 31-32 degrees by 7000rpm.

It only knocks when I change gear or mash the gas pedal hard in a low gear at high RPM.

So if I roll into throttle in 2nd gear it shows negative knock and timing is around 31 degrees, then when I shift 2nd-3rd the moment I let clutch out and back on gas its sits at +5.99 with timing sub 20 degrees. If I come off the gas and roll back into throttle it goes back to negative.

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