DEI fuel rail shield write up

AWayne

AWayne

TJ Enthusiast
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Oct 22, 2023
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Lake Cumberland, Kentucky
Took the time to replace the factory heat shield, as I was having some issues that felt like vapor lock. For instance, would go into Walmart, come out, and would have a rough idle for a few minutes until I drove around for a minute. I took pictures of everything so I wouldn't forget what I'd done, so here we go with a half-assed write up.

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Step 1: disconnect the battery.
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Step 2: remove your CCV hoses. I broke mine. Don't do that. Or, plan on it and get the parts beforehand. 47057, 47079, 42344 are the Dorman Motormite numbers. Then, remove your air intake hose.
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Step 3: Disconnect your throttle/ cruise linkage. Should be able to use some needle nose and pinch the ends, and pull through the bracket. Remove the bracket as well.

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Step 4: remove the clip between fuel line and fuel rail. Your fuel line is still attached via the locks inside the line.

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Step 5: remove the fuel line. Place a rag under the line. It will have fuel come out. Mine was a 3/8 line disconnect.
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Step 6: remove you injector plugs. The red clips will probably shatter.

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Step 7: remove the 4 bolts on your fuel rail. The one by your IAC will be difficult to remove, so you may want to unbolt it first.

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Step 8: remove the injector clips. They have a bit of pressure, so they may fly away. Be careful.
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Step 9: remove your fuel rail. It'll take some effort. They fit tight. Just apply even pressure on both sides, or you may damage an injector or the rail. You will lose fuel. Place a rag underneath. Prepare for it to be soaked in fuel.
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Bonus pic of my factory heat shield. It definitely seen better days.
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Step 10: cover your rail. I removed mine and cleaned wirh brake cleaner beforehand. I also had to make a hole for the pressure regulator/sensor.
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Step 11: install the manifold heat shield. It uses the head bolts. Middle lines up with the throttle body. Injector wiring cover holds it down.
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Step 12: install new injector o rings. Or, replace if they're damaged. I just changed my o-rings.
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Step 13: bolt everything back up. Don't forget the injector clips!
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Step 14: should be done now! Just make sure everything is tight and mostly looking like it did before, aside from the shiny new cover.
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I got the K Suspension kit similar to the DEI, haven't installed it yet. But now that I need to fix a manifold gasket leak, looks like it will be happening then. Not sure if totally necessary here in the PRoMD, but my '05 had the manifold shield and it was pretty ratty and slightly oil soaked. Pulled the pieces of it out last weekend to get access to the manifold fasteners...hitting them periodically with penetrating oil with the hopes of making the leak repair go a bit easier.
 
I replaced mine with the DEI kit from K Suspension along with new/rebuilt 4 hole injectors at 113K earlier this year. Kit included fuel rail, intake and injector shields. I did mine without removing all the things you did with no issues. I had the PO303 code so I replaced the injectors, some wee cracked, but it turned out to be a bad spark plug causing the code. Easy peezy job any way you do it.

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bucky said:
I replaced mine with the DEI kit from K Suspension along with new/rebuilt 4 hole injectors at 113K earlier this year. Kit included fuel rail, intake and injector shields. I did mine without removing all the things you did with no issues. I had the PO303 code so I replaced the injectors, some wee cracked, but it turned out to be a bad spark plug causing the code. Easy peezy job any way you do it.

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I could definitely see doing it without disconnecting everything. I just wanted to clean everything, and I had to change my CCV stuff and valve cover gasket anyways.
 
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My misfires were caused by my #3 fuel injector getting too hot and vapor locking. I wrapped the #3 injector with insulation which cured it. Nice writeup on what you did for the fuel rail.
 
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In your 16'th photo, your injector is cracked, you should consider looking for replacements. believe it to be a somewhat common thing, dont believe it to be a critical issue but something to keep on your mind for later on service.

I checked all of mine while doing this job and didnt find any with cracks, but good write up and the added suggestion of new injector o-ring seals (y)
 
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Insulation works both directions in slowing heat transfer.

I had the DEI fuel rail cover and injector jackets for a while. It was a double edge sword. It might have slowed down the heat soak. But eventually the heat soaked in, the added insulation kept the rail and injectors hot longer than if they were uncovered.
 
I have wondered if the DEI kits is more reflective than insulating? My 05‘ already has the shielding down by the manifold. I was thinking what could be non conductive, insulating , and able to take the under hood temperature- heater hose. So a little afternoon playing around I wrapped the fuel rail and supply line all the way to the frame. Taking advantage of fuel running through it keeps it cool. I used a temp gun on it before and after a test run and it was significant drop in temp, I will have to see if I can find those numbers again. Ideally it would be great if that DEI kit would fit over the Heater hose so it had that reflective component.

edit/addition: I took a temp reading allowing a full 5 min idle time at the end of my drive home commute with high 90’s ambient air temp. Full 25 degree drop in rail surface temp.

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jjvw said:
Insulation works both directions in slowing heat transfer.

I had the DEI fuel rail cover and injector jackets for a while. It was a double edge sword. It might have slowed down the heat soak. But eventually the heat soaked in, the added insulation kept the rail and injectors hot longer than if they were uncovered.
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Try some hood vents for cooling your insulation. ;)
 
Apparition said:
Try some hood vents for cooling your insulation. ;)
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Already got those. Venting the hood actually did quite a bit towards mitigating the heat soak. It still happens on occasion. But the frequency and duration became less.
 
jjvw said:
Already got those. Venting the hood actually did quite a bit towards mitigating the heat soak. It still happens on occasion. But the frequency and duration became less.
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Then your only choice is to move back to Minnesota where it rarely gets hot enough to be an issue.
 
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Jerry Bransford said:
My misfires were caused by my #3 fuel injector getting too hot and vapor locking. I wrapped the #3 injector with insulation which cured it. Nice writeup on what you did for the fuel rail.
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Thanks! So far, no issues. I let it sit and idle for about 20 minutes earlier, then shut off for a few, and started right back up with no issues. Kit seems decent enough quality. I would've liked for the injector sleeves to be a bit more fitted, though. They're just kind of slapped around. But I guess the kit would also cost quite a bit more for that lol
 
JustDandee said:
I have wondered if the DEI kits is more reflective than insulating? My 05‘ already has the shielding down by the manifold. I was thinking what could be non conductive, insulating , and able to take the under hood temperature- heater hose. So a little afternoon playing around I wrapped the fuel rail and supply line all the way to the frame. Taking advantage of fuel running through it keeps it cool. I used a temp gun on it before and after a test run and it was significant drop in temp, I will have to see if I can find those numbers again. Ideally it would be great if that DEI kit would fit over the Heater hose so it had that reflective component.

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The rail cover fits pretty tight, so I doubt it would fit over the heater hose. You could always try some of their other wraps do some more custom fitting. The plug wire shields may be a good candidate!
 
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AWayne said:
Thanks! So far, no issues. I let it sit and idle for about 20 minutes earlier, then shut off for a few, and started right back up with no issues. Kit seems decent enough quality. I would've liked for the injector sleeves to be a bit more fitted, though. They're just kind of slapped around. But I guess the kit would also cost quite a bit more for that lol
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I got the p/n for my injector sleeve from the Jeep TSB for misfires on the 2004. That sure cleared my #3 misfire. It says it's an ignition shield but that's what Jeep used in their TSB for the misfire. https://www.amazon.com/gp/product/B007O3QHDK/?tag=wranglerorg-20

Fuel Injector Insulation .jpg
 
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Jerry Bransford said:
I got the p/n for my injector sleeve from the Jeep TSB for misfires on the 2004. That sure cleared my #3 misfire. It says it's an ignition shield but that's what Jeep used in their TSB for the misfire. https://www.amazon.com/gp/product/B007O3QHDK/?tag=wranglerorg-20

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I'd seen that listed before at work! Always wondered what it actually went on. Do you think it would be beneficial to put it on all injectors, or just the number 3 for the TSB?
 
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