Heat shield material under fuel injectors

YZ80 · Feb 8, 2022

Anyone have some feedback on if the heat shield material between the fuel rail and injectors and the top of the manifold is really necessary?
I removed what was left of the stock sheet when I replaced the fuel injectors and didn't replace it. I tested out the new 4 hole injectors and when i got back I lifted the hood to feel the fuel rail. It was surprisingly very warm.

Tob · Feb 8, 2022

Injector heat soak is a common issue. I'd leave the insulation there - it's there for a reason. There are even kits that add insulation sleeves to the injectors and replace the manifold heat shield to fix this issue. If it was tattered, I don't blame you for tossing it, but I'd recommend replacing it.

Jay MacLeay · Mar 1, 2022

YZ80 said:
Anyone have some feedback on if the heat shield material between the fuel rail and injectors and the top of the manifold is really necessary?
I removed what was left of the stock sheet when I replaced the fuel injectors and didn't replace it. I tested out the new 4 hole injectors and when i got back I lifted the hood to feel the fuel rail. It was surprisingly very warm.

I replaced my heat shield with this after suffering the dreaded cylinder 3 heat soak misfire issue. Haven't had any issues since.
https://www.designengineering.com/97-04-jeep-4-0l-i6-fuel-rail-injector-cover-kit/

Irun · Mar 1, 2022

I've installled both of these and the later is the better quality. It will help with the heat soak issue.

https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20
https://www.amazon.com/gp/product/B015NOKWQY/?tag=wranglerorg-20

slayerwatcher · Mar 29, 2022

I've installed this insulation kit and I'm still getting the heat soak issue. GRRR!!! Any recommendations? Thanks in advance.

Oki TJ · May 10, 2022

YZ80 said:
Anyone have some feedback on if the heat shield material between the fuel rail and injectors and the top of the manifold is really necessary?
I removed what was left of the stock sheet when I replaced the fuel injectors and didn't replace it. I tested out the new 4 hole injectors and when i got back I lifted the hood to feel the fuel rail. It was surprisingly very warm.

i have recently ordered the 4 hole injectors. Wondering if i should change them my old ones out even though theyre still good

YZ80 · May 10, 2022

Oki TJ said:
i have recently ordered the 4 hole injectors. Wondering if i should change them my old ones out even though theyre still good

The 4 hole injectors are better. My 4.0 is running smooth. Really easy to replace and i put on the heat shield kit as well I recommend it

Wtrask · May 10, 2022

Replace it! It’s also to keep debris off the exhaust manifold. My Jeep caught fire after a squirrel built a nest in there after my Jeep sat for a few days. You can install it without removing the injectors. Trust me you don’t wanna deal with the hassle of finding the parts to fix a fire.

WWII-Willys · May 21, 2023

I got a little confused as to which Shield Kit was preferred?

Number One - This One?

Number Two - This One?

(or)

Number Three - This One? (The DEI which is cheaper thru Quadratec?)

Any tutorials online?

Thank You

gabriel w · Apr 13, 2025

WWII-Willys said:
I got a little confused as to which Shield Kit was preferred?

Number One - This One?

Number Two - This One?

(or)

Number Three - This One? (The DEI which is cheaper thru Quadratec?)

Any tutorials online?

Thank You

Hello, which of the three options did you buy in the end?

Irun · Apr 13, 2025

1 and 3 are the same, both made in USA DEI. I've had both the DEI and the cheap China knockoff. The quality difference between the two is noticeable. Stay with the made in USA version.

TinkerDV · Apr 13, 2025

Irun said:
I've installled both of these and the later is the better quality. It will help with the heat soak issue.

[URL]https://www.amazon.com/gp/product/B08TTT8GVM/?tag=wranglerorg-20[/URL]

[URL]https://www.amazon.com/gp/product/B015NOKWQY/?tag=wranglerorg-20[/URL]

The bottom DEI is good stuff. I put it on mine.

TJRick · Apr 14, 2025

Did all TJ's supposed to have this heat shield?

My 1998 4.0 doesn't have one, and I don't remember one ever being there. And I do not - nor have I ever - had heat soak issues of any kind?

TinkerDV · Apr 14, 2025

I had a CJ I swapped a 96 4.0 in and at that time it didn't have them.

TJRick · Jul 7, 2025

TJRick said:
Did all TJ's supposed to have this heat shield?

My 1998 4.0 doesn't have one, and I don't remember one ever being there. And I do not - nor have I ever - had heat soak issues of any kind?

I think I found out the answer to my own question.

The heat soak issues may be caused by the later 1999+ "horseshoe" intake manifold that replaced the earlier "log" style. The earlier style allowed much more heat to escape compared to the later style:

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Heat shield material under fuel injectors

YZ80

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Tob

Weimar problems require Weimar solutions

Jay MacLeay

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Irun

A vicious cycle of doing, undoing, and re-doing!

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YZ80

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Wtrask

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WWII-Willys

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gabriel w

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Irun

A vicious cycle of doing, undoing, and re-doing!

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