Cracked Intake

Digg In

Digg In

1st TJ ever
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Joined
Dec 21, 2023
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21
Location
Hampstead NC
CEL. Whistling noise after engine warm up. Noise continues at idle. Code: Lean fuel cylinder 1, misfire. With the help of a friend, I removed the intake manifold. The port at cylinder one is missing a corner on the intake. Could this be my problem? A couple of the fuel injector o rings were missing. I need another intake. I have an 06. Can I use any intake from a 97-06? I am thankful for this forum, and your help.

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That would definitely cause the codes you got.

I know there was a manifold change somewhere around 99, but I'm not certain whether they're interchangeable. Even if they physically interchange, I think the flow characteristics are different so it might interfere with the tuning/performance. I would stick with 2000 or newer just to be safe.

Sorry, I don't have any manifolds laying around to ship to you. 🤣
 
freedom_in_4low said:
That would definitely cause the codes you got.

I know there was a manifold change somewhere around 99, but I'm not certain whether they're interchangeable. Even if they physically interchange, I think the flow characteristics are different so it might interfere with the tuning/performance. I would stick with 2000 or newer just to be safe.

Sorry, I don't have any manifolds laying around to ship to you. 🤣
Click to expand...

Sir, I need you on speed dial. 153K miles. What causes these intakes to crack? Thanks.
 
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I know the 2000-2001 went to a coil pack, and the heads were prone to crack. But I’m not sure if the intakes are interchangeable.
 
Digg In said:
Sir, I need you on speed dial. 153K miles. What causes these intakes to crack? Thanks.
Click to expand...

I'm honestly not sure. This is a new one for me. If there was a bolt hole in the cracked section I'd say a previous owner overtorqued it. I'm trying to think if there's something in that area that somebody would have used the manifold as something to pry against.
 
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You need the "new" style if you want everything to bolt right up and have the correct connections in the right places for vacuum etc.

Some people put the new ones on to replace the old log style manifolds for better performance, but the gains are questionable, and they have to make the connections work. There may also be issues with the pwr steering mount, etc.

Old style log manifold:
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I just want to make an integrated exhaust and intake that bolts right to a turbo in one neat package.

Sometimes you can weld those intakes back together...but well then you'd also need all the parts! And welding oil contaminated aluminum is a disaster.

-Mac
 
JKP said:
You need the "new" style if you want everything to bolt right up and have the correct connections in the right places for vacuum etc.

Some people put the new ones on to replace the old log style manifolds for better performance, but the gains are questionable, and they have to make the connections work. There may also be issues with the pwr steering mount, etc.

Old style log manifold:
View attachment 496797
Click to expand...

This is not the same as mine.
 
JKP said:
You need the "new" style if you want everything to bolt right up and have the correct connections in the right places for vacuum etc.

Some people put the new ones on to replace the old log style manifolds for better performance, but the gains are questionable, and they have to make the connections work. There may also be issues with the pwr steering mount, etc.

Old style log manifold:
View attachment 496797
Click to expand...

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Yes, you need the newer of the 2 styles. You can swap them with some effort and modifications, but that's not what you are looking to do I'm sure.
 
TJ4Jim said:
Intake manifold cracking is not really a common occurrence and usually happens when the manifold is not properly seated and it's over torqued during installation.
Click to expand...

According to all the information that I've read, a cracked exhaust manifold is a common occurrence on the Early TJ's. The reason is because there is no flex. The upgrade has flex in the manifold. I researched it after mine was cracked and I replaced it. I guess the defect could be compounding. If the intake is cracked, and would be suspicious of the exhaust manifold. Just a thought.
 
ChasUGC said:
According to all the information that I've read, a cracked exhaust manifold is a common occurrence on the Early TJ's. The reason is because there is no flex. The upgrade has flex in the manifold. I researched it after mine was cracked and I replaced it. I guess the defect could be compounding. If the intake is cracked, and would be suspicious of the exhaust manifold. Just a thought.
Click to expand...

One has really nothing to do with the other as the exhaust manifold is a very common defect that does not occur at the connection to the block but further downstream due to stresses created by the constant heating and cooling by exhaust gases. That isn't an issue with the intake side where its's commonly caused by a "whoops" during installation.
 
TJ4Jim said:
One has really nothing to do with the other as the exhaust manifold is a very common defect that does not occur at the connection to the block but further downstream due to stresses created by the constant heating and cooling by exhaust gases. That isn't an issue with the intake side where its's commonly caused by a "whoops" during installation.
Click to expand...

A whoops from the factory, correct?
 
freedom_in_4low said:
I'm honestly not sure. This is a new one for me. If there was a bolt hole in the cracked section I'd say a previous owner overtorqued it. I'm trying to think if there's something in that area that somebody would have used the manifold as something to pry against.
Click to expand...

I replaced the intake manifold. Whistle noise is gone, and no more codes. Jeep runs perfect. There are a couple of minor issues but none affect the drivability. Thanks for help.
 
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