93 yj 4.0 high idle after new header install

creepytj98

Member
Joined
Mar 25, 2010
Location
Clemmons, NC
My buddy has a 93 yj with the I6 it came with a cracked exhaust manifold and we replaced it sunday. Well when we cranked it up it idled at about 2300 for about 30 second then droped to 2k. I've checked and double check all the vac lines. None seem to be off or miss placed. I told him to run it for a little while then unplug the battary for a night. Its dropped to about 1500 now. I think it just the motor getting use to the new header. Anyone heard of this happening after a new header is installed?
 
The intake and exhaust share the same gasket. Did you put a new gasket on? Are the bolts tight? This will cause the problem you described.
 
Sounds like a vacuum leak. Any chance the intake is not sitting on the dowels properly? Happened to me a time or two. Also, were the bolts torqued? 25 ft/lb IIRC.
 
Yea new gasket. And my guessing the dowles are those little metal things the header goes on. If so yea. We didn't torque them with a torque wrench but there tight I checked mutiple times. I've check the vac lines over and over and they all seem to be hooked up
 
creepytj98 said:
Yea new gasket. And my guessing the dowles are those little metal things the header goes on. If so yea. We didn't torque them with a torque wrench but there tight I checked mutiple times. I've check the vac lines over and over and they all seem to be hooked up
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After you've gotten them hot, they need to be re-torqued.
 
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