Should I be worried about this noise?

vxr500

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This is my first 4.6 Mustang and i've read they can be noisy. My car has a slight knocking sound at idle and it increases with rpm. I never hear it while diving though. I did listen to some youtube vids of cam phasers and rod knock, and it doesn't sound like that. Vids:


 

skwerl

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Sounds like normal injector noises. At least the second video anyway.

I heard two knocks at about 4 seconds into the first video, not sure what that was.
 

vxr500

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Yeah that’s the loose exhaust pipe when I give it throttle. Here’s one more vid by the fender..

 

vxr500

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That's no injector knock. That sounds like actual knock.

That’s what I was afraid of. Should I back down the tune from 93 to 89? It does seem to run ok otherwise.
 

07gts197

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Adaptive knock should kill any knock when using lower grade fuel when tuned for higher grade. When I got sick and my dad started driving my 07 gt unbeknownst to me he was filling it with 87 but it was tuned for 93. 3 years later no issues and no knocking.

If the tuner turned off the knock sensors thats another story... Its hard to tell but it sounds more like a lower end knock. Kind of a dumb way to do it but you could unplug each injector one by one to narrow down the cylinder thats affected. Youll know because itll stop knocking. Although it will throw codes for injector circuit open circuits...
 

eighty6gt

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another blown up 3v... knocking and pounding :( :(

maybe put an oil pressure gauge on it?

It will _not_ knock at idle even with 50 octane fuel. Zero load.
 

Dino Dino Bambino

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Use a mechanic's stethoscope to localize the noise. It's hard to tell just from the video if it's bad cam phasers or something more sinister like a rod knock.
Check the oil pressure at hot idle and at 2000rpm. Low oil pressure would point towards worn rod bearings.
 

vxr500

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Update, I Sea Foamed it, put new NGK iridiums in, a new fuel filter, and had a full synthetic oil change done. Car runs great, oil pressure good, but knock sound still there. I also backed the tune down from 93 to 91 octane, but still run 93. I guess I just won't worry about it until something gets worse. Car has 84k miles.
 

Steve Waters

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2015-08-18_19-00-46_609-1.jpg Did you find the area or side of the engine the knock is comming from? You may want to take the valve covers off and check all your cam lobes. I had a similar knock and it turn out to be a bad rocker and lobe. I had to replace them. Car ran fine. Don't let it go to long the metal shaving could migrate all over the engine.
 
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