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View Full Version : Setting idle via Throttle Body.



Slow96GSR
26-08-2006, 10:40 PM
Note: Works on all Honda/Acuras and most others but not all. Some throttle bodies come preconfigured from the factory. Change settings at your own risk. If you still don't know what to do after reading this take it to a pro. This is not to be used for tuning, just for setting up your throttle body after installation or reinstallation. The terms may be different but you all should get the picture! Made this for a friend on here and thought I would post this for everyone. Pictures are of an Edelbrock throttle body, still the basic setup of a Honda throttle body. Enjoy and good luck. Ok end of note!

There are three ways to set up your cars idle with a basic throttle body.
1: Idle set screw on the upper front of the housing above the intake pipe. See picture 1.
2: Butterfly stop set screw on the right lower side of the housing. See picture 2.
3: Throttle cable length set nuts. See pictures 3 and 4.

The first thing you need to check before installing your throttle body is the butterfly stop set screw on the right lower side of the housing. The flap needs to close all the way but not too much as if you go too far is just starts to reopen. The set screw should come set from the factory but just in case here is how to set it. When you "tighten" the screw you are opening the flap and this allows more air in making the rpms rise. "loosening" the screw closes the flap allowing less air in and this lowers the rpms. Got to far and you will just start to reopen the flap. See picture 1.

Once you have the throttle body installed and it is all hooked up you can begin to configure the throttle cable length. The cable should have some play in it but only about 1/8 of an inch in either direction. There is two nuts on the cable, one is the set screw that holds the cable in place and the other is what keeps the cable and nuts from spinning and shifting. The set screw is a six sided 12mm nut and the other is an oddly shaped multi sided nut. Move the multisided nut toward the throttle body and you will shorten the cable thus opening the butterfly flap allowing more air in and raising the rpms. Moving this nut away from the throttle body will lengthen the cable, which closes the butterfly flap letting in less air and lowering the rpms. Too far and the wide-open throttle position will be lowered. Also too much slack can cause poor throttle response. See pictures 3 and 4.

Last but not least is the easiest part to set, the idle set screw. The idle set screw is located on the upper front of the throttle body housing above the intake pipe. If you need to raise your rpms just “loosen” the screw and this will raise your rpms. To lower the rpms just “tighten the screw. This can be done easiest with the motor running. You can set the rpms to where you would like them. See picture 1.

Picture 1:
http://www.strathlan.com/CMS/images/DIYPictures/ThrottleBody/Picture1.jpg

Picture 2:
http://www.strathlan.com/CMS/images/DIYPictures/ThrottleBody/Picture2.jpg

Picture 3:
http://www.strathlan.com/CMS/images/DIYPictures/ThrottleBody/Picture3a.jpg

Picture 4:
http://www.strathlan.com/CMS/images/DIYPictures/ThrottleBody/Picture3b.jpg

edw-R
29-08-2006, 12:20 PM
Very clear !! Good write-up !!

Civic_Si
30-08-2006, 02:35 PM
Hi Slow96GSR,

Wow! Great DIY posting on adjusting the idle rpm on the throttlebody!
I will try it on my car tonight!
But I am doubtful that it will fix the idiotic Skunk2 throttlebody I have on my Si.... I will be pulling it out next week!
THANKS FOR THE GREAT POST!!!

Regards,
Civic_Si

Slow96GSR
30-08-2006, 05:20 PM
E-mail me pics of it. I want to see if they sent out the right one or if it is the same one we got you in that package the first time. If it's the same one send it to me and I'll try to get you in to a Edelbrock T.B. or get the right one from Skunk2 and set it up here. Edelbrock put more in to designing the fit of their parts then skunk I guess and that's why I have no issues and you seem to be having a bad time. I bet it is something simple but I will help as much as I can.

EuroDude
30-08-2006, 06:10 PM
Nice DIY! :D

Although IMO its important and good practise to identify the source of the Idle problem and fix that, before "patching" the problem by adjusting the Idle Screw :thumbsup:

For instance with my Civic, its cold idle was sitting at 2500rpm and the warm idle was hunting around 1000rpm->1500rpm. After cleaning the Throttle body, IACV, and FITV, it completely fixed all the idle problems. I didnt need to adjust the idle screw at all.
If I simply adjusted the Idle screw, who know how the engine would react, it probably would have lost significant power and/or efficiency and confuse the ECU, and made the idle hunting even worse.

Slow96GSR
31-08-2006, 10:59 PM
Well this was more towards people who just installed a new throttle body or removed the stock one for cleaning. It’s not for fixing problems that aren’t the throttle body’s fault. It still wouldn't fix that problem and can lead to more expensive fixes later on.

czy_sol87
23-07-2007, 11:41 PM
my idle screw seems to be really loose, is there something i can put on it so when adjusted it wont move at all???

czy_sol87
09-08-2007, 12:29 PM
i was talkin to a honda mechanic and he told me how to set ur idle at honda specs

what u have to do is turn the idle screw all the way in
then turn back 2.5 rotations and thats the optimum setting