Jeep TB high idle

[EclipseStyle97]

i know this question/problem has been posted before because i remember reading about it a while back. i searched for about 3 hours last night trying to find it again but i had no luck so please excuse the repeat in question. alright...i finished the jeep TB mod last night and its on my car but im idleing around 2800 rpms. when i interchanged the little nipple things on the IAC i checked the heigth of the tip and screwed the jeep one in until it was at the same heigth. i pluged the 1/2 inch idle port on the intake manifold very well so i dont think thats the problem. the butterfly is completely shut also so no air is gettin in there. (i know i still have to adjust the idle screw so it doesnt stick when it first opens.) i dont think i have any leaks around the gasket but im going to double check that today when i get home from school. anyway ive played with the tip of the IAC several times and i still cant get the idle right and im really at a lose of what to do. my car also shakes really bad when i touch the throttle or let it off. is that because its idleing too high or because i still have to adjust the butterfly flap? any tips could help. thanks

 

[Doug99RS]

What did you plug the original Idle air control air path with?

Did you hook up all the vacuum lines?

What kind of gasket did you use at the throttle body to upper intake?

Did you modify the upper intake manifold?

The tip for the IAC motor may need to be backed out even further in order to fully seat against the throttle body. You can't really use the measured height of the two motors as a good judge. Reason being that the motor moves in and out depending on desired idle speed or last throttle position if the engine was shut off when the throttle plate was off idle.

If the throttle plate is fully closed to the housing, the idle set screw has not been adjusted and is not holding the plate open then you've got two other possibilities. First being an uncontrolled vacuum leak i.e. vacuum hose off, poor fitment with the new gasket at the throttle body, or the plug you used for the smaller hole is not sealing properly. The second possibility is a controlled vacuum leak at the idle air control motor. If the tip is too far in, the motor will try and run it in as much as possible. If the full travel is not enough to close off the whole then air will still continue to pass through that opening thus giving you the high idle.
Doug

 

[EclipseStyle97]

thanks for the tips but i forgot to reply to my own post yesterday saying that i got it to work. as soon as i got home from school i took it off and adjsuted the tip of the IAC motor. and then i noticed i had about a 1/16 in. gap between the throttle position sensor and the throttle body. so i got some shorter screws and got that down tight. after i put the TB back on and fired it up my car idled a hair above 1000 rpms. and that was also w/me reseting the idle screw. that was all fine and dandy but then i saw that there was a vacume line unhooked. i know where it went on the 2g TB but i had no idea where to put it on the new one. so i plugged it up with a screw. weather that was a bad thing or not i dont know-haha. oh yeah i plugged up the original hole with a metal bearing type thing and some JB weld. (it sealed beautifuly) but anyway i do still have one problem. when i let off the throttle the rpms tend to stay where they are at for a couple seconds and sometimes go up 200 rpms, then drop down to 1100 really slow. i can deal w/it but it would be so much better if they dropped quickly. i figure it is something with the IAC motor but im not sure. any suggestions there? by the way thanks for replyin to my post with some advice. i didnt think i would get any since it was a repeat question. thanks again
-adam

 

[Doug99RS]

You'll need to get a vacuum source for that hose that you can't find a home for. It's an emissions component and will throw a check engine light here shortly if it remains blocked off or lacking the vacuum. You can tap in at the vacuum tree in the middle to middle/passenger side of the manifold. It may/will require some slight hose modifications since it' a different size than what's on the throttle body.

As for the sticky throttle... some of it is the nature of the beast since we've taken out half of the spring assemebly. BUT you should make sure that the spring is not wedging itself between the throttle body and the throttle shaft. Refer to other Jeep TB threads here on tuners for more info on that same problem and the fixes.
Doug

 

[EclipseStyle97]

you talkin about the vacum tree that is green (i think) its plastic and has a cap on one of the ends? if thats the right one, thats where i put that hose to-haha. but there was no need for adapting a hose. it fight right up. i put a clamp on to secure it. anyway thanks alot for all your help, i really appreciate it. i love the new TB. the power gain is amazing and im still on my stock intake and airbox so im assuming im not using it to its 'full potential.' . i just ordered a short ram intake today though and the store said it'd be in tomorrow. im excited-haha. anyway, thanks again dude.

-adam

 

[Doug99RS]

No, the piece with the green cap is an emissions test port. I'm talking about on the intake manifold itself next to the intake air temperature sensor.

 

[wookieneck]

I drilled and taped the hole directly under the TB , put a nipple in there and the lonley vacum line hooked right up without any modification. But it sounds like you sealed that up ?

 

[EclipseStyle97]

haha yeah i plugged it up pretty good. the only way i think ill get that out is with a hammer and chizzle and about 3 hours of pounding-haha. i just put it on the vacume tree. thanks for the input though. it would have been a good idea-. btw i wish my tb conversion looked that nice and shiny
-adam

 

[wookieneck]

Im pretty happy with it thus far. The only thing that bothers me is when I come to a stop , the rpms kinda hang at about 2k and then slowly fall to a normal idle. Any thoughts?

 

[BlueMoonEclipse]

Hey btw does annyone have a writeup on the Jeep TB conversion..pics would be nice

 

[Doug99RS]

http://www.geocities.com/lover232/Enjoy.html
http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

 

[EclipseStyle97]

Originally posted by wookieneck
Im pretty happy with it thus far. The only thing that bothers me is when I come to a stop , the rpms kinda hang at about 2k and then slowly fall to a normal idle. Any thoughts?

yeah mine does the same thing. i kinda get imbarased (sp?) at stop lights cause people probably think im being a dick and reving my motor or think im riding my clutch REALLY bad in stop and go traffic. even though i dont cause i usually pull out around 1200. o'well but like you, i love it other then that reason. it was the best kick in the balls for my car. i even have a cheap ractive shortram intake on it whistles like a beast. sounds like i got turbo haha. but yeah i love it.
-adam

 

[BlueMoonEclipse]

Ty for links

 

[90swhip]

"Im pretty happy with it thus far. The only thing that bothers me is when I come to a stop , the rpms kinda hang at about 2k and then slowly fall to a normal idle. Any thoughts? "

Anyone have a better answer to this inconvenient issue? I think this is a common problem with this mod. I'd really like to know if there's a fix! Thanks!

 

[goodbuds]

8 years not bad....