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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech

idle problem?

  • Thread starter Thread starter mustanglouie
  • Start date Start date Mar 11, 2006

mustanglouie

Member
Dec 30, 2004
152
0
16
Oakwood GA
Mar 11, 2006
#1
  • Mar 11, 2006
  • #1
Ok I have recently done a complete motor overhaul and have put on the new goodies that you see in my sig. I have the common idle issues that comes with changing HCI stuff. So trying to help the problem I have installed a brand new IAC. Well ever since I did that my idle sits at 2000 rpms. I have ajusted the screw on the throttle body and messed with the clip that it is attached to. So I don't know what to do. I know the new IAC can't be bad. And it was idling like crap before but now it is really bad. I don't want to put the old one back on so what am I missing. Is there a ajustment on the IAC some were. Please help me out. thanks
Louie
 

CManT1914

New Member
Feb 5, 2004
3,172
2
0
Killeen, Texas
Mar 11, 2006
#2
  • Mar 11, 2006
  • #2
Have you tried turning the screw that opens or closes the IAC?
 

zkillrr

Member
Dec 22, 2004
97
0
16
Memphis.Tn
Mar 11, 2006
#3
  • Mar 11, 2006
  • #3
This question and fixes have been going on on this site alot this year. Everyone has had an idle issue even me that is how i know! Do a search on this forum tech, put in idle and you will get about 200
pages of good info on how to fix it. Once i got my idle back down to around 900rpms I had to buy a iac restrictor plate to get the rpms to fall when shifting. If you have anymore ?s pm me
 

R.J.

Member
Aug 20, 2003
813
0
16
Warwick, Rhode Island
Mar 12, 2006
#4
  • Mar 12, 2006
  • #4
Try this:

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC. You are done.
 

mustanglouie

Member
Dec 30, 2004
152
0
16
Oakwood GA
Mar 12, 2006
#5
  • Mar 12, 2006
  • #5
ok I did a search and found some useful info but I just don't understand why I am having this problem with a brand new IAC. I have done all the stuff like turning screws and adjusting stuff and even disconneting my battery for a while to let it reset. I just don't understand it. I guess I just need to put my old one back on and just deal with the idle surge.
Another thing to is that when I unpluged my new IAC the car still idles at 2000 rpms but with my old one the car wouldn't stay running? Kinda seems funny to me.
 

mustanglouie

Member
Dec 30, 2004
152
0
16
Oakwood GA
Mar 12, 2006
#6
  • Mar 12, 2006
  • #6
sorry double post
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Mar 12, 2006
#7
  • Mar 12, 2006
  • #7
Sounds like you have something mechanical wrong.

Maybe the throttle cable is in a bind or something went wrong when you put the isc on.

Grady
 

mo_dingo

20+ Year Stangneter
Aug 26, 2003
3,031
2
58
Tucson, AZ
Mar 12, 2006
#8
  • Mar 12, 2006
  • #8
Either the throttle body blade is too far open, the IAC screw is too far open, or the IAC valve is stuck open. My guess is the latter. A brand new part is not necessary a working part.

Which part did you get? if you got the generic autozone one, it won't work. You need the Borg-Warner one from pep boys which looks like the stock one.
Scott
 

69clark

Founding Member
Sep 25, 2002
731
7
18
Ravena, NY
Mar 13, 2006
#9
  • Mar 13, 2006
  • #9
I have heard of quite a few IAC's being bad even though they were brand new.
 
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