2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

What would cause you to not be able to lower the idle enough?

Old Oct 15, 2002 | 06:31 PM
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Question What would cause you to not be able to lower the idle enough?

I can't get my idle below about 1200-1400 RPMS ... this is with the car fully warmed up. I have used the set inital jumper and turned the idle set screw as far in as it will go .. and it wont drop below this. I have completly unplugged the BAC and still will not drop low enough. I am getting this thing smogged this week .. but they will fail me with this high a idle. What would cause this?

Thx
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Old Oct 15, 2002 | 06:35 PM
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i'm in the same boat you are...but i have until next june to figure out a way...but since you're asking...
i'd like to know too...anyone???
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Old Oct 15, 2002 | 06:36 PM
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Cold start cam not releasing properly.

Throttle set screw in too much.


-Ted
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Old Oct 15, 2002 | 06:38 PM
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Cold start cam not releasing properly.
Throttle body dirty.
Throttle set screw in too much.


-Ted
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Old Oct 15, 2002 | 06:41 PM
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hmm, those are thoughts. I cleaned up the throttle body real good when i set my TPS... I used the voltage meter on my S-AFC to set that. Anything obvious to look for on the cold cam? or any write up's?

the inside of my throttle body is immaculate. I cleaned it up real good during the rebuild.
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Old Oct 15, 2002 | 06:44 PM
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well, on mine, it idles fine before it warms up, even after driving it for a few minutes (2-3mins)...once it warms up, the idle pretty much stays at about 1200-1400 rpm...and will drop down to about 800-100 rpm on occassions
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Old Oct 15, 2002 | 06:44 PM
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If I adjust the throttle set screw .. should I open the Idle screw a few turns first? then turn the throttle set screw out .. and finish the adjustment again with the idle screw? does that sound like the right method? Also .. why would those settings change from doing a rebuild? just maybe getting bumped or somthing?
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Old Oct 15, 2002 | 06:45 PM
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Originally posted by RETed
Cold start cam not releasing properly.
Throttle body dirty.
Throttle set screw in too much.


-Ted
Yep, i second this, the only thing is, be carefull when ******* with the throttle screws.
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Old Oct 15, 2002 | 06:46 PM
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I have more or less the same issue.. Mine idles high 1600 ish when cold .. 1200-1400 when warm. and like 500 when started warm .. run it a few mins back up to 1200-1400 to stay .. untill i shut it down again. then it does the whole thing over.
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Old Oct 15, 2002 | 06:48 PM
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i'd like to know more about the cold start cam...where is it? what does it do? and how can i check it?
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Old Oct 15, 2002 | 06:50 PM
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Originally posted by biorotary
i'd like to know more about the cold start cam...where is it? what does it do? and how can i check it?
I second that also. And would a upgraded radiator have a effect on this? I never get over about 1/8 on my temp guage .. even after Hrs of driving.
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Old Oct 15, 2002 | 08:59 PM
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For the love of the bump
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Old Oct 15, 2002 | 10:14 PM
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check the cruise control cable... if you tightened that cable too much... then your idle will never drop enough.
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Old Oct 15, 2002 | 10:18 PM
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Originally posted by Cheers!
check the cruise control cable... if you tightened that cable too much... then your idle will never drop enough.
Ya, I thought about that .. so I have it tottaly disconnected right now.. thx for the sugestion though.
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Old Oct 15, 2002 | 10:23 PM
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it's probably from cleaning the TB.. you just opened up more air gap that was other wise blocked with dirt and crap. I remember spraying intake cleaner into my old car and the idle went up like 400rpm after and had to be reset.

do you have slack in the thottrol cable?
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Old Oct 15, 2002 | 10:32 PM
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Originally posted by Scott 89t2


do you have slack in the thottrol cable?
Ya I have a decent amount of slack .. I took off the IC again tonight ... double checkked the TPS.. and I was loking for the throttle stop screw. But I could not find anything that seemed to be stopping it.. I am assuming that it is being stopped from inside .. by the plates or somthing.

I have removed my secondary plates.
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Old Oct 15, 2002 | 10:46 PM
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the plates would do it too there should be a screw on the outside that holds the plates open a bit.
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Old Oct 15, 2002 | 10:52 PM
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Ya I saw one screw on the outside... but it was still about 2mm from hitting the end of that screw when it is completly closed.

the screw im talking about is a very short ... maybe 1/2 a inch long screw ... on the top of the firewall side of the upper intake.

Last edited by Rpeck; Oct 15, 2002 at 10:54 PM.
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Old Oct 16, 2002 | 10:20 AM
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The morning bump... I'm still open for sugestions.

Another thing I noticed .. my A/F guage goes to all the way lean when I am at idle Not sure if thats of ill effect or not.

And I get a popping noise when I am at my constant high idle... I'm thinking I may have a mixture issue.

Last edited by Rpeck; Oct 16, 2002 at 10:23 AM.
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Old Oct 16, 2002 | 10:41 AM
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rob, just a question, have you checked to see if the throttle actually comes all the way back?
reason i'm asking is because your omp arm (the metal rod between the throttle body and the omp) can be rubbing against the coolant hose going to the bac and not letting the throttle return to it's "normal" position causing a high idle...
btw, i got mine down to a solid 750 rpm this morning...
one problem was what i had just mentioned above and the other one was my throttle set screw...
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Old Oct 16, 2002 | 10:57 AM
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Originally posted by biorotary
rob, just a question, have you checked to see if the throttle actually comes all the way back?
reason i'm asking is because your omp arm (the metal rod between the throttle body and the omp) can be rubbing against the coolant hose going to the bac and not letting the throttle return to it's "normal" position causing a high idle...
btw, i got mine down to a solid 750 rpm this morning...
one problem was what i had just mentioned above and the other one was my throttle set screw...
I'm pretty sure its comming all the way back .. If i give it a good tug to doesn't seem to want to go any further. I didn't see anything obstructing it when I looked last nite... but If the throttle set screw is the one I think it is ... (I explained it above) it is not comming back all the way to touch that .. but I don't see anything external in the way.. I am thinking maybe somthing is wrong inside, or it is a mixture issue ... I do have slcak in the thottle cable though when it is fully released.
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Old Oct 16, 2002 | 11:06 AM
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well, got me then...cause after i adjusted the omp rod, my rpm dropped from about 1400 rpm to about 1000 rpm, then i backed out the throttle set screw and now i'm at a good looking 750 rpm +- 50rpm
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Old Oct 16, 2002 | 11:17 AM
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Originally posted by biorotary
well, got me then...cause after i adjusted the omp rod, my rpm dropped from about 1400 rpm to about 1000 rpm, then i backed out the throttle set screw and now i'm at a good looking 750 rpm +- 50rpm
Is the throttle set screw the one I describe above? am I looking at the right screw?
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Old Oct 16, 2002 | 11:25 AM
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Theres a small chance the bac valve is stuck open more than it should be at . Take its plug off after the car is warmed up and see if the rpms drop down.
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Old Oct 16, 2002 | 11:48 AM
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Originally posted by Rpeck

Is the throttle set screw the one I describe above? am I looking at the right screw?
sounds like it is...
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