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| jennkent5454 |
 Posted: Thu Jul 03, 2008 2:27 pm Post subject: high idle 1550-2000 |
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Newbie
Joined: 22 Apr 2008
Posts: 33
Location: texas
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| i just replaced my exhaust manifold, all in all it went ok. but now i have it all back together and it idles really high. between 1500-2000, i have checked and rechecked all electrical connections, and vacuum lines that i removed, i dont get it. |
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| Marlin4622 |
| Posted: Thu Jul 03, 2008 5:21 pm Post subject: |
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Famous
Joined: 09 Jan 2008
Posts: 211
Location: Patterson, California
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would the old O2 sensor that was bad be screwing with your idle mixture??
Just a thought. Maybe replace the 02 sensor. |
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| DailyDrivenTJ.com |
| Posted: Thu Jul 03, 2008 7:34 pm Post subject: |
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Site Founder
Joined: 09 Apr 2006
Posts: 1768
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Good try Marlin4622. 
I just happened know too well why this is happening.
Jenn, you have a what they call a vacuum leak. Engine is trying to compensate for the lost vacuum through idling high; sucking more air in to see if the vacuum is restored. Since the sufficient vacuum is not reached, the engine just keeps idling high.
I am confident in saying that you did not seat the intake manifold square along with the exhaust manifold on the cylinder head; causing the air leak into the intake.
This usually happens when you don't clean up the gasket mating surface thoroughly, both on the head and the intake manifold.
OR another thing is, you might have missed the guide pin, sometimes this has to be lined up perfect on the manifold for it to seat correctly.
Either way, it is the vacuum leak causing the high RPM idle.
You will have do the job all over again making sure both manifolds seat flush against the head.
If you have any other questions, don't hesitate to ask!
Michael |
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| jennkent5454 |
| Posted: Thu Jul 03, 2008 7:46 pm Post subject: |
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Newbie
Joined: 22 Apr 2008
Posts: 33
Location: texas
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the new gasket will still work?
I guess it will have too work!
Since its 8:00pm on a holiday weekend. |
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| DailyDrivenTJ.com |
| Posted: Thu Jul 03, 2008 9:54 pm Post subject: |
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Site Founder
Joined: 09 Apr 2006
Posts: 1768
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If the gasket you just installed did not get damaged, say cracked, cut, or torn, it can be reused. Just remember that you need air tight seal around that intake manifold!
Speaking of the leak, make sure all the hoses that are connected to the manifold are not leaking vacuum, or sucking in air from the engine bay!
-mk |
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| jennkent5454 |
| Posted: Fri Jul 04, 2008 8:10 pm Post subject: |
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Newbie
Joined: 22 Apr 2008
Posts: 33
Location: texas
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the problem has been solved!!!!!!!!!!!!!!
it had to do with the two dowels, but the reason for the problem was when i had the manifold replaced by the pros, at some point the right bracket on the intake that sets on the dowel was snapped off, allowing the manifold to fall down enough that it wouldnt seal. the front bracket was still there, so with the front one on the dowel i had to have someone hold the rear up to as close to front as possible while i was underneath tightening it all up, so i think its all good now, the jeep almost won. |
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