Bronco Nation

Engine knock during cold crank

cdsinfla
Nov 08, 2024

Rank 0

Nov 08, 2024

Just picked up a 2023 2.7L Big Bend Sas with 5000 miles. When it's engine has been sitting for an hour or more, it knocks when I crank it. Fairly loudly for about 2 seconds then quiets down. Doesn't do it near as bad or at all if it's recently been started. Maybe octane sensor reading the fuel octane then adjusting? I run 87 in it.

Thanks for any thoughts!

Love my Bronco!

Nov 08, 2024

#1
Sounds like cam phasers are going out. It’s covered under warranty. I just had mine replaced for the same thing.
UserError, Chief Ron

Gladesmen

Nov 08, 2024

#2
Yep get that checked out ASAP. Hope it’s an easy fix.
Bronco Nation 1100. Everglades, Desert Sand
Res: 7/30/20 ordered 1/22/21 reorder 10/15/21 changed to Everglades 3/9/22 schedule 8/29/22 bumped to 9/5; 9/7/22 blend, 9/9 Mods, 9/26/22 completed, 10/7 shipped, 11/3/22 delivery
UserError, Chief Ron

KCsBronco

Nov 08, 2024

#3
Yeah, as mentioned you should have dealer check those Czp’s out. Until then, may help to do a 15 - 20 second engine prime on cold starts.

It’s easy, simply fully depress both brake & accelerator pedals while pushing engine start/stop button. This’ll circulate oil up the top and reduce that knock.

Cheers
Chief Ron, Jakob1972

Rank V

Nov 08, 2024

#4
cdsinfla
Just picked up a 2023 2.7L Big Bend Sas with 5000 miles. When it's engine has been sitting for an hour or more, it knocks when I crank it. Fairly loudly for about 2 seconds then quiets down. Doesn't do it near as bad or at all if it's recently been started. Maybe octane sensor reading the fuel octane then adjusting? I run 87 in it.

Thanks for any thoughts!

Hello! If you send us a message with your VIN and mileage, I would be happy to take a further look into your engine concerns.
Chief Ron

Rank 0

Feb 06, 2025

#5
cdsinfla
Just picked up a 2023 2.7L Big Bend Sas with 5000 miles. When it's engine has been sitting for an hour or more, it knocks when I crank it. Fairly loudly for about 2 seconds then quiets down. Doesn't do it near as bad or at all if it's recently been started. Maybe octane sensor reading the fuel octane then adjusting? I run 87 in it.

Thanks for any thoughts!

Anyone have an idea of why the knock would suddenly stop? Sounds normal now which worries me...

you can tune a guitar but can't tune a fish

Feb 06, 2025

#6
cdsinfla
Anyone have an idea of why the knock would suddenly stop? Sounds normal now which worries me...

Cracked piston skirts will do that. Pintos had that problem.
Joined May 29, 2020 Member 546
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