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Solving Idle/surging Issues With Iac Mod

  • Thread starter Thread starter varunner
  • Start date Start date Jun 18, 2014
V

varunner

New Member
Jun 16, 2014
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Jun 18, 2014
#1
  • Jun 18, 2014
  • #1
Hi All,

I'm a new member here. I have a 95 mustang GT auto trans. Engine is stock except for headers, CAI. I recently added a different cam, very mild specs. So as others have experienced, the idle is rough, somewhat expected, but the problems is that it dies when put into gear, and also pretty bad surging in idle and in gear. I checked thoroughly for vacuum leaks. So after searching for help by moding the IAC, I put an extra gasket in place and cut through both of them creating an open space between the 2 air holes giving it a constant by-pass. At the same time I re-set the idle using the procedure found on this site. This greatly improved the idle, and eliminated the surging, and so far it doesn't die when put into gear. So my question is how do I fine tune this modification ? Just by ear ? O2 sensor reading ? I don't have a WB O2 now, but plan to. Thanks in advance. Great site btw.

Brian
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
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Jun 18, 2014
#2
  • Jun 18, 2014
  • #2
They actually make a little plate that goes under the IAC that you can adjust the bypass with two little allen screws. It's not very expensive. It's something that we used to use in the long long ago. Now everyone runs a tune anyway, and you can adjust it through the tune, so there really isn't a need. Do you happen to know what your vacuum is at idle?

Kurt
 
V

varunner

New Member
Jun 16, 2014
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Jun 18, 2014
#3
  • Jun 18, 2014
  • #3
Vacuum at idle is around 15" I have a tweecer. Do you know if the bypass can be regulated with a tweecer ?


revhead347 said:
They actually make a little plate that goes under the IAC that you can adjust the bypass with two little allen screws. It's not very expensive. It's something that we used to use in the long long ago. Now everyone runs a tune anyway, and you can adjust it through the tune, so there really isn't a need. Do you happen to know what your vacuum is at idle?

Kurt
Click to expand...
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
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Jun 19, 2014
#4
  • Jun 19, 2014
  • #4
15" of vacuum is plenty. You should be able to adjust the IAC to hold a good idle with a tweecer without any bypass modification. Keep in mind that the IAC is a common failure item. An old IAC can cause problems controlling idle.

Kurt
 
V

varunner

New Member
Jun 16, 2014
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Jun 19, 2014
#5
  • Jun 19, 2014
  • #5
That's good to hear. Would you have any experience with a tweecer doing this ? what parameters, setting ? thanks
Brian
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,289
1,631
214
Acworth, GA
Jun 19, 2014
#6
  • Jun 19, 2014
  • #6
Unfortunately I have no experience with the tweecer. We used to have quite a few people on here that messed with the tweecer setup, but most people have swapped to the Moates Quarterhorse now. I've never messed with either.

Kurt
 
V

varunner

New Member
Jun 16, 2014
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Jun 19, 2014
#7
  • Jun 19, 2014
  • #7
I found about 6 different settings for ISC in the tweecer. A couple of them deal with idle speeds, so I'll have to try a couple of things. Not sure if I'll undo what I did to the gasket or not. Sure would be nice if I could find some good tuning info. Just a little info here and there. thanks

Brian
 

toyman

10 Year Member
Jul 19, 2007
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Vernon BC
Jun 19, 2014
#8
  • Jun 19, 2014
  • #8
Have you checked the TwEECer Tuning Manual sticky in this forum?
 
V

varunner

New Member
Jun 16, 2014
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Jun 20, 2014
#9
  • Jun 20, 2014
  • #9
Nope, But I sure will. thanks
 
V

varunner

New Member
Jun 16, 2014
17
1
1
Jun 22, 2014
#10
  • Jun 22, 2014
  • #10
Seems all is good now. In addition to the gasket mod I did, I found a conflict within tweecer. There was an idle setting associated with the ISC that had to be within 100 rpm with the Idle in neutral and Idle in gear setting. Thanks for the help.

Brian
 
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