Illusive false knock.

[Crashxx]

Hello, I have a 2025 F-150 w/ Gen6 Whipple stage 2, and Stainless Works long tube headers w/ 3" exhaust to the rear. I'm having some remote tuning being done by Oz Tunes. I keep getting a false knock as soon as I go WOT, which is pulling timing so I'd like to get that figured out. Have any of you experienced the same thing and if so, what did you find to be causing it? Thanks.

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[Davidwnuc]

Hope this helps. I have no experience with it just read about it before.

https://www.mustang6g.com/forums/threads/false-knock-culprits.149971/

https://www.f150forum.com/f123/2018-5-0-header-install-428296/

 

[SALEEN961]

This list of possible causes is very long if you get into specifics. Some common issues are loose heat shields rattling, anything touching the engine that could rattle or vibrate when you go WOT, slip yoke binding, vibrations from the suspension, ect. On my 2014 5.0, I had lots of false knock from my Circle D torque converter; on my 2021 3.5EB I have lots of false knock from the wastegates.

 

[Riddick]

Does your truck have long tube headers or aftermarket exhaust? If so, crawl under there and hit the exhaust in random places with the palm of your hand or a rubber mallet. If you hear anything rattling this could definitely produce false knock. Ensure the exhaust and all the exhaust clamps are clear of the body/frame of the truck. Under heavy load, the engine can twist a little bit and if you're exhaust is close to the frame or anything it could be hitting it under load.

Before you install the blower did you happen to notice the orientation of the knock sensors in the top of the block? If the connector for the knock sensor is touching the block that can also cause false knock. You want to adjust them so both sides of the sensor are clearing the block.

Outside of this I would double check everything that was tampered with during the supercharger install. Any loose components can cause a vibration which can lead to false knock.

Are you sure you have a good tank of fuel in there? It won't hurt to add some octane booster just to rule out the fuel.

 

[Crashxx]

Thank you all for the reply's. I will work thru the suggestions.

 

[beefcake]

Just need to get under there make sure nothing is touching try to bang around see if anything is loose check heat shields or anything that can move around. False knock can be a pain

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