Spark knock? Really?

[Anthony Palazzolo]

Hello everyone, Im new to the forum so please give grace if this question/issue has been raised before.
I just purchased a 2018 raptor w/18000 mile very clean truck. The issue im having is that at approx
4500-5000- rpm WOT im getting what sounds like a mild spark knock. after 5000 rpm or so it goes away . it does not continue after letting off the gas, its only at wide open throttle. I put octane booster thinking it was some cheap gas, No difference. Could this be a timing issue ? cam Phasers? I honestly haven't heard spark knock in decades. Thanks to everyone in advance.

 

[NASSTY]

What octane are you running?

 

[Anthony Palazzolo]

regular . im thinking 87

 

[NASSTY]

That's probably why.

 

[smurfslayer]

have you repeated the testing in 4a?
IWE issues manifest similarly, an audible click to rattle sound.

If you don’t get the issue in 4a, your IWE system is the issue. the check valve is the first point of failure, like 7 bucks on Amazon, could also be the solenoid or tubing.

 

[FordTechOne]

regular . im thinking 87

There’s your problem. These engines are designed for 93 octane.

 

[Bulldog82]

Use 93, don’t mix.

 

[xrocket21]

use 91 or better, change the plugs

 

[TopElement]

regular . im thinking 87

Wow, in a performance vehicle? Nothing less than 91 unless it's an emergency.

 

[Anthony Palazzolo]

Just put an entire tank of 93 and still getting the spark knock sound. . also. repeated the test in 4A and was identical. if in sport mode sometimes pinging will continue after letting off if trans is holding onto the gear. Its faint but noticeable at 5000 plus rpm and around 60 mph.