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Exhaust manifold install probs

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Just like I knew that it would happen, my MJ runs like crap after the new manifold I installed. It ran great prior to the install but was loud due to several cracks.


It has a wicked surge to the idle right now, to the point it will stall. I am going to clean and inspect the IAC to see if it is the cause.


It also has a wicked bad hesitation as soon as you touch the gas, either just sitting or driving it will almost stall than catch and take off like a screaming monkey.


Also, I had to disconnect the vacume line that runs to the diaphram that controls the exhaust gasses back into the intake, it runs like @$$ with it connected but runs good without it.....whats the issue there?


I also marked the injectors prior to removal, but with my luck all my numbers rubbed off and can not figure the correct spots for the for the injector harness. It runs totally fine no matter how I run the injector harness....no miss, stalling or anything, full power no matter what I do. Is there a way to figure out the correct locations?


Once driving the MJ runs great, much more pwerful than before, it just has the idle problem and the hesitation problem.....anything will help at this point....


Thanx in advance!!

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Hey Redbull it's 01TJay from TJHardcore... anyway... I had a buddy had the same problem. His was caused by the intake not sealing up properly and allowing air to flow in at the head. He took it apart and re-sealed the intake and it ran fine.


That doesn't mean that's what's going on necessarily with yours though. It's just something I remember happening to a buddy.


How's the TJ?


later, j

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It does sound like a vaccuum leak, likely the intake manifold. Did you get all the manifold bolts back in, and tight?


The other component you are mentioning is the EGR valve. It is normally closed at idle and on acceleration....it gets a vac signal from the solenoid (follow the vac line out of it, across the back of the engine to the passenger side, and you'll find the solenoid, ECU controlled). Sounds like your EGR valve itself is stuck (partially) open. At idle, with the exhaust tube connected, it should not be allowing exhaust into the intake.


Sounds like you have a couple problems.



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ok, I replaced the knock sensor b/c I smashed it. I replaced the IAC. I checked for leaks. I replaced the MAP sensor. I welded the EGR tube from exhaust to intake.


It seems to idle fine (a little high but fine) and has a ton of power but it still has the wicked hesitation. The funny thing is, if I disconnect the vacume to the MAP sensor the hesitation goes away and idles normal (a little lower)


I also adjusted the TPS from memory.........I search for the post on TPS adjustments but I can't find it...anybody got a link.


So, with that said.....what does it mean??!!?? Any ideas?

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Hey Redbull it's 01TJay from TJHardcore... How's the TJ?


later, j


The TJ is good, just finished the full hydro and I am re-doing the rear suspension to tuck the arms up higher. I have a few minor things to do before the Chili Challenge.


I am going to sell my 40s and get some comp krawlers......

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Thanx guys.......I was very very frustrating to replace your exhaust and your injectors start dumping fuel down the motors throat. The crappy thing was, you could not tell it was running rich....no soot or smoke out the exhaust.


I am kinda suprised of the new found power......I can crank a patch with 3.55 gears and 35 inch tires.


Now I have to move onto swapping in my 8.8. If anyone is intersted.....ruffstuff has great swap brackets, even if your staying spring under.

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