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Swapping an L86(6.2) into a 5.3 (L83)

Gavin Faulkner

By Gavin Faulkner
in Engines & Drivetrain

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Gavin Faulkner Enthusiast

Gavin Faulkner

Posted
Posted

Hey everyone,

I just completely blew my motor up yesterday in my 2015 Silverado 5.3 w 6L80. I am wondering what it takes to swap the 6.2 into my truck. as far as harnessed and what not. id love any input i can get. 

Thanks 

BC0573E4-C003-45A6-85FC-854A32710F62.jpeg

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CamGTP Senior Enthusiast

CamGTP

Posted
Posted

If you buy a 2014-2015 6.2 engine it's basically plug and play with the harness, nothing is really different. The later years after 2016 I believe run a different high pressure fuel pump so the connector is different.

 

The rest is tuning.

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  • 7 months later...
gat0r Enthusiast

gat0r

Posted
Posted

just in case, for others on this topic....

 

Fuel pump control module harness

2014-16 are 4 pin and the 2017+ are 3 pin

  • 1 year later...
AztekxBeast New Member

AztekxBeast

Posted
Posted
On 11/2/2023 at 10:19 PM, gat0r said:

just in case, for others on this topic....

 

Fuel pump control module harness

2014-16 are 4 pin and the 2017+ are 3 pin

Do you know if there is a way to swap that part of the harness out or to change from 4 to 3 vice versa? I have a 2014 with 5.3 looking to swap to 6.2 and I have seen more later model 6.2s in DFW.

AztekxBeast New Member

AztekxBeast

Posted
Posted

From the research I have found I am happy that I can continue to use the 4L80e that I have lol. It was rebuilt in march so I have like 1-2k miles on it. From what I can see my only concern is the fuel pin connectors between newer models if I can't find a decent motor thats in my year range for direct bolt up. I didn't plan on doing a full rebuilt just the cams and heads to get rid of that nasty AFM. I was also given full bolt on exhaust from my cousin so that as well but I do want something reliable that will last me years to come for sure. 

 

Motor mounts for the 6.2 from 5.3 are also direct bolt ons and placement?

  • 3 months later...
mayutt Enthusiast

mayutt

Posted
Posted

I drive a 2014 Sierra 1500 SLT with an L83. It has over 220K and still runs great, but I'm starting to research an engine swap as I intend to re-engine and keep driving it when this one goes.

 

I see the L86 is a direct form/fit/function minus some tuning...my question is regarding the Flex Fuel sensor. Since my truck is factory Flex Fuel, will it be fine to run the L86 on ethanol too (if I install a rebuilt L86 vice L83)?

  • 1 month later...
M1ck3y Senior Enthusiast

M1ck3y

Posted
Posted
On 3/25/2025 at 7:17 AM, mayutt said:

I drive a 2014 Sierra 1500 SLT with an L83. It has over 220K and still runs great, but I'm starting to research an engine swap as I intend to re-engine and keep driving it when this one goes.

 

I see the L86 is a direct form/fit/function minus some tuning...my question is regarding the Flex Fuel sensor. Since my truck is factory Flex Fuel, will it be fine to run the L86 on ethanol too (if I install a rebuilt L86 vice L83)?


yes the l86 can run on e85 but it has to be turned on in the tune. 

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