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

What are your thoughts on this?

  • Thread starter Thread starter Methodical
  • Start date Start date Jan 24, 2006

Methodical

15 Year Member
Dec 1, 2003
1,192
11
59
Clinton, MD
Jan 24, 2006
#1
  • Jan 24, 2006
  • #1
I've read in several MM&FF issues (i.e. Ask Bernie/Yo Ken columns) over the years, even in the new issue and in other publications/forums that you can drill either a 1/8" or 1/4" hole in the throttle blade and that will help an unstable idle. However, I've never to date seen where anyone has been advised to do that on this forum. What do you think? Does it work or not? And if it does work, which year Mustang does it work on?

Peace
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Jan 25, 2006
#2
  • Jan 25, 2006
  • #2
It can make for an annoying whistle. That advice can be for foxes which really would benefit from an adjustable IAC plate.

Since SN's have the bleed adjuster (the allen-head fastener under a plastic/rubber grommet on the front of the IAC), I would use it instead. Foxes dont have this option stock (hence why the throttle blade is drilled).

Good luck.
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Jan 25, 2006
#3
  • Jan 25, 2006
  • #3
Well Al

To me it seems like a bunch of Poop

On the other hand ... I've seen peeps on these forums say it works.

Also seen peeps on these forums say ... It don't

My thoughts about this have always been .........

A small hole or the slightest bit more crack of the tb blade .............

Whats the difference
each method is gonna let a bit more air flow past the blade.

Besides

You and I both know the prob behind this whole deal is ............

the true amount of air flow
and
the air flow values in the pcm don't match
thus
freaking out the little silver box

Grady
 

Black95GTS

Active Member
Jan 8, 2004
1,644
3
38
Marlborough, MA
Jan 25, 2006
#4
  • Jan 25, 2006
  • #4
Methodical said:
I've read in several MM&FF issues (i.e. Ask Bernie/Yo Ken columns) over the years, even in the new issue and in other publications/forums that you can drill either a 1/8" or 1/4" hole in the throttle blade and that will help an unstable idle. However, I've never to date seen where anyone has been advised to do that on this forum. What do you think? Does it work or not? And if it does work, which year Mustang does it work on?

Peace
Click to expand...

I have seen this work on a 91 Fox. I got too because I really made fun of the kid for doing it. Then he fired it up and the thing idled like stock. I think it was an F cam.

I'm not sure how this would work with our EECs. Grady, wouldn't the MAF see the air if you drilled a hole in the tb?

I do agree though that drilling a hole should be the absolute LAST resort after you've tried everything. Clean the sensors, set the TB voltage, etc etc and if all else fails and you don't plan selling that T/B any time soon, then I would probly try drilling it.

Adam
 

95Vert

New Member
Aug 19, 2004
1,785
0
0
North Mexico (deep south Texas)
Jan 25, 2006
#5
  • Jan 25, 2006
  • #5
This is very interesting since I'm thinking of switching to a 93 TB set-up. I hope the guys with the swap chime in.
 

Methodical

15 Year Member
Dec 1, 2003
1,192
11
59
Clinton, MD
Jan 25, 2006
#6
  • Jan 25, 2006
  • #6
I thought this was interesting and was thinking out loud. Yes Grady I agree as I use the Tweecer and EA to work on my idle. Again just was thinking out loud.

Peace
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Jan 25, 2006
#7
  • Jan 25, 2006
  • #7
Methodical said:
I thought this was interesting and was thinking out loud. Yes Grady I agree as I use the Tweecer and EA to work on my idle. Again just was thinking out loud.

Peace
Click to expand...

What do you think Al?

A tiny hole in the tb blade

OR

Very slight increase of tb blade opening with the stop screw

What is the difference

I just can't see how there would be any difference

Grady
 

CManT1914

New Member
Feb 5, 2004
3,172
2
0
Killeen, Texas
Jan 25, 2006
#8
  • Jan 25, 2006
  • #8
final5-0 said:
What do you think Al?

A tiny hole in the tb blade

OR

Very slight increase of tb blade opening with the stop screw

What is the difference

I just can't see how there would be any difference

Grady
Click to expand...

Well, when we turn the stop screw, the blade opens, and the TPS is changed as well. If he drills a hole, the TPS stays where it should. That would effect things.
 

Black95GTS

Active Member
Jan 8, 2004
1,644
3
38
Marlborough, MA
Jan 25, 2006
#9
  • Jan 25, 2006
  • #9
CManT1914 said:
Well, when we turn the stop screw, the blade opens, and the TPS is changed as well. If he drills a hole, the TPS stays where it should. That would effect things.
Click to expand...

Thats very interesting, I didn't think of it. Since you're just trying to get it to idle you don't want that TPS going anywhere if you can avoid it. Although, if you disconnected the battery after you did the drilling, wouldn't the computer learn that slight opening as "idle"?? Would you drill, then set the voltage?

Are we thinking too far into this?

Screw it all, I'm switching to carb.

- tuning with a flat head > tuning with a laptop
 

Pokageek

Active Member
Jun 10, 2005
2,767
0
46
MA, USA
Jan 25, 2006
#10
  • Jan 25, 2006
  • #10
I am using the IAC plate I bought from a dude on this site. If that is what you are speaking of, it works.
 

illwood

Member
Apr 3, 2004
636
1
19
Worcester, MA
Jan 25, 2006
#11
  • Jan 25, 2006
  • #11
Black95GTS said:
Screw it all, I'm switching to carb.

- tuning with a flat head > tuning with a laptop
Click to expand...


Can I have your TwEECer R/T then?

Pokageek said:
I am using the IAC plate I bought from a dude on this site. If that is what you are speaking of, it works.
Click to expand...
No, they were talking about physically drilling a hole in the butterfly in the throttle body.
 

Blackened302

Active Member
Jul 21, 2005
1,439
0
36
South TX
Jan 25, 2006
#12
  • Jan 25, 2006
  • #12
95Vert said:
This is very interesting since I'm thinking of switching to a 93 TB set-up. I hope the guys with the swap chime in.
Click to expand...
that's exactly what i was thinking. i say it's worth a shot.
 

RIO5.0

15 Year Member
Feb 16, 2001
6,892
8
128
N.H.
Jan 25, 2006
#13
  • Jan 25, 2006
  • #13
I have run 2 different Fox TBs and never had idle issues...once a full idle reset was done....I have an Accu 75 but haven't tried that one just yet...Gonna wait on that one til the next phase...

This is an 93 Cobra that came with the upper....has hole...Idled fine..This one was ported some and the blade polished..It whistled...you can see the taper in the entry compared to the Ex..


This 96 Explorer unit is what I currently run...Had the hole...Idles fine.


Accu 75...No hole..
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Jan 25, 2006
#14
  • Jan 25, 2006
  • #14
Black95GTS said:
I have seen this work on a 91 Fox. I got too because I really made fun of the kid for doing it. Then he fired it up and the thing idled like stock. I think it was an F cam.
Click to expand...

It is kinda hard to argue against something that works

I'm not sure how this would work with our EECs. Grady, wouldn't the MAF see the air if you drilled a hole in the tb?
Click to expand...

Seems to me your reasoning is correct cause the maf has already metered the air by the time it gets to the tb

I do agree though that drilling a hole should be the absolute LAST resort after you've tried everything. Clean the sensors, set the TB voltage, etc etc and if all else fails and you don't plan selling that T/B any time soon, then I would probly try drilling it.

Adam
Click to expand...

Grady
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Jan 25, 2006
#15
  • Jan 25, 2006
  • #15
CManT1914 said:
Well, when we turn the stop screw, the blade opens, and the TPS is changed as well. If he drills a hole, the TPS stays where it should. That would effect things.
Click to expand...

Right as Rain Mr. Chris

I just might have to start callin ya

Terry Tuner

Like Al said above ... I'm just thinkin out loud
but
The amount of change in the tps would not be that much
THEN AGAIN
If one had his tps set right on the verge of the maximum closed voltage,
using the stop screw could push the closed setting beyond the limit.

I still say ... just get it aroung .85 volts ... give or take a bit

All this fuss from all of us guys over a little hole

Having said that .................... I'll leave now

Grady
 

CManT1914

New Member
Feb 5, 2004
3,172
2
0
Killeen, Texas
Jan 26, 2006
#16
  • Jan 26, 2006
  • #16
Black95GTS said:
Thats very interesting, I didn't think of it. Since you're just trying to get it to idle you don't want that TPS going anywhere if you can avoid it. Although, if you disconnected the battery after you did the drilling, wouldn't the computer learn that slight opening as "idle"?? Would you drill, then set the voltage?

Are we thinking too far into this?

Screw it all, I'm switching to carb.

- tuning with a flat head > tuning with a laptop
Click to expand...

Supposedly our PCM's baseline the TPS at startup, meaning they use whatever voltage it reads as the "idle" voltage. However....... MANY guys (myself included) have good results from setting their TPS back to .9volts or so if/when it gets out of whack. Disco'ing the battery will not effect the TPS reading, as it's a "hard part", meaning where it sits, is where it sits. It's gonna read "xxx" voltage before and after you disco the battery.

final5-0 said:
Right as Rain Mr. Chris

I just might have to start callin ya

Terry Tuner

Like Al said above ... I'm just thinkin out loud
but
The amount of change in the tps would not be that much
THEN AGAIN
If one had his tps set right on the verge of the maximum closed voltage,
using the stop screw could push the closed setting beyond the limit.

I still say ... just get it aroung .85 volts ... give or take a bit

All this fuss from all of us guys over a little hole

Having said that .................... I'll leave now

Grady
Click to expand...

lol, Terry Tuner? You're gonna have to explain that one to me Gramps!

You're right, the slight change that one usually needs to change the idle does not generally move the TPS too much. But like you said, if it's already at .99volts or so, that "slight" change can throw everything out of whack. I wish I could get mine below 1.1volts, I need to take it back off and readjust it, instead of messing with the stop screw, but I'm lazy, lol.

Plus, my CEL came on yesterday for the first time since my h/c/i, so something's up. It only comes on at idle though, so knowing my luck, it's something to do with that BLASTED TPS!! (especially since I JUST adjusted it the other day, then BAM my CEL comes on)
 

donkey_punch

New Member
Jan 16, 2004
565
0
0
northern****ingjersey
Jan 27, 2006
#17
  • Jan 27, 2006
  • #17
i have a hole drilled in my stock TB. once i had the cam and heads done, the lowest it would idle was 1200. and with the exhaust system i have, that's just too loud of an idle. lol so the gentlemen that did the swap for me drilled a small hole in the TB and got it down to about 1000, and it wouldn't bouce once it was warmed up.
once i got it home i played around with the idle adjustment screw and got it just under 1000 about 800-900. on cold starts it bounces around and will stall if left alone. i just hold the gas lightly so it doesn't bounce and stays steady. once it's warmed up it's fine.
 
You must log in or register to reply here.

Similar threads

Hard to start when engine is cold
  • 86_Capri
  • Mar 11, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
32
Views
890
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 21, 2026
CAMTWO1070
Tuners come on inside
  • squeak93
  • Feb 13, 2026
  • SVT Tech Forum
Replies
1
Views
238
SVT Tech Forum Feb 20, 2026
squeak93
B
2001 roush stage 3 - sat for 5 years
  • Brando_05
  • Aug 26, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
247
1996 - 2004 SN95 Mustang -General/Talk- Aug 26, 2025
Brando_05
B
S
Fox '87 GT can't get to stay running
  • spilly
  • Mar 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
27
Views
684
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 20, 2026
spilly
S
S
Help with window and possible engine
  • StefRena22
  • Jun 12, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
19
Views
842
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 21, 2025
Willybill32
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?