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General Forums => The Mess Hall => Topic started by: Clem on July 22, 2010, 09:22:09 AM
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All,
I started getting a high idle on the jeep yesterday when stopped at a stop light. (1200-1500 rpm). I checked the codes. I get 12, 33, and 55. All acceptable. I replaced the MAP sensor. No dice. I left the battery disconnected overnight to clear the computer. The jeep started right up and went to 800-ish rpms. I kicked it around the block and it started idling funny again. (1200-1500 rpm) I came back to the house, disconnected the battery, and swapped out the TPS. I pulled the codes again and got 12, 33, and 55. The battery was disconnected for around 10 minutes. I hooked the battery back up and kicked it around the block. It is still idling fast. (1200-1500 rpm)
It has a 4.0 throttle body that has been installed for several years with no other issues.
I am at a loss. What am I missing? :brick:
Thanks for looking.
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sounds like a vac leak or (but you had it for a while and it's unlikely) you did not replace the Idle Air control Valve and housing - look at the housing, does it say 2.5 or 4.0?
check the rubber elbow that's on the line going from the valve cover to the intake manifold under the t/b, sometimes that cracks and would leak vacuum which would cause high idle. Check other fittings on the manifold as well to see if there are any of them with a problem, could also be one that goes to the dash climate control or the one that goes to the t-case for front axle disconnect - you can remove them off the fittings on the manifold and put your finger on top of the fitting to see if the idle goes down (except for the MAP one, that needs to be plugged). Other thing i can think of is if the throttle lever on the t/b is not going all the way back down (maybe the cable gets stuck) so try to push it back down by hand and see if that's helping.
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I reset the computer. I replaced the fittings and line goingto the map sensor. It runs normal with the vacuum disconnected from the map. Tines are all in good shape.
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I reset the computer. I replaced the fittings and line goingto the map sensor. It runs normal with the vacuum disconnected from the map. Tines are all in good shape.
so if all i said before checks out ok might be gunk in the IAC valve that prevents it from getting back all the way, look at that also
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I would pull the throttle body and all the sensors, giving the TB and IAC housing a good bench cleaning.
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Bounty Hunter, I did... The last culprit in the circuit is the IAC. I am thinking it is bad.
Now everyone will get a kick out of this. I have been running the 4.0 IAC for several years now. Other than idling fast on start up, it does fine. Mine DOES NOT say 2.5 on it. I have my old throttle body, but no IAC. :confused:
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Bounty Hunter, I did... The last culprit in the circuit is the IAC. I am thinking it is bad.
Now everyone will get a kick out of this. I have been running the 4.0 IAC for several years now. Other than idling fast on start up, it does fine. Mine DOES NOT say 2.5 on it. I have my old throttle body, but no IAC. :confused:
maybe it was plugged up and finally cleared out what was in there lol
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It has been this way for a few years. I have broken down the throttle body a few times to clean it out.
I am going to swap the 2.5 IAC on it tomorrrow.
Thanks everyone for your input. :thumbsup:
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It has been this way for a few years. I have broken down the throttle body a few times to clean it out.
I am going to swap the 2.5 IAC on it tomorrrow.
Thanks everyone for your input. :thumbsup:
let us know how that works out
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An update:
I found the source of the headache... I sprayed a bit of starting fluid around the intake/exhaust manifold gasket. I got a change in rpm's. I swapped the 2.5 liter IAC housing back on with no effect. I also found out that the IAC motor uses the same solenoid for the 4 or 6. The plunger is different. The plungers can be swapped out. The 4 banger plunger is smaller than the 6. The plunger, spring, and shield unscrew from the the end of the IAC. More worthless info for those hard pressed for an IAC motor. :pot:
An intake manifold gasket it is... Thanks for the input everyone. It's greatly appreciated. :beers:
Does anyone here have any experience with Remflex gaskets? The theory is that they are supposed to seal better due the expansive nature of the gasket material.
http://catalog.remflex.com/category_s/46.htm (http://catalog.remflex.com/category_s/46.htm)
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Here is their "why we are better" page...
http://catalog.remflex.com/category_s/154.htm (http://catalog.remflex.com/category_s/154.htm)
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Update to the update...
The corner of the intake, around the #1 injector, is broken off. I found the vacuum leak. Lol! Pics later after a few beers...
Anyone have an intake and exhaust manifold they want to sell?
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Update to the update...
The corner of the intake, around the #1 injector, is broken off. I found the vacuum leak. Lol! Pics later after a few beers...
Anyone have an intake and exhaust manifold they want to sell?
I did a while ago but I think it all went to salvage cause nobody wanted it
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sharpxmen gets prize for vacuum leak! Lol!
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sharpxmen gets prize for vacuum leak! Lol!
oh well, i probably listed so many possible causes that it was hard to miss :lol: