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  • Fox 5.0 Mustang Tech

She stalls everytime i have the A/C on

  • Thread starter Thread starter WICKED50LTR
  • Start date Start date Jul 18, 2005
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WICKED50LTR

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Aug 28, 2002
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Central NJ
Jul 18, 2005
#1
  • Jul 18, 2005
  • #1
I cant figure it out, everytime i put the a/c on and im sittin at idle she will just fall flat on her face. Even if its on low or full makes no difference. but when im driving shes fine, but the second i slow up or come to a stop, bang shes stalled again. Anybody else have these issues? Could it be because of the cam or the pulleys? On a day when its 95 out i didnt pay 600 bucks to have the a/c fixed for nothing.
 
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AmMscl

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Feb 14, 2004
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CALI
Jul 18, 2005
#2
  • Jul 18, 2005
  • #2
Might want to try to clean T-body or idle air solenoid...if that doesn't work try adjusting TPS

What does it idle at and what cam?
 
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SamSnyder

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Mar 30, 2005
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Jul 18, 2005
#3
  • Jul 18, 2005
  • #3
Idle air solenoid, aka idle air bypass. Clean it out with Gummout. When working right, it should be capable of raising your idle to 1200 or even 1400 RPM, and that means plenty of room to adjust for the ac compressor kicking on. Gunk in it not only reduces the airflow, lowering the top number, but it also slows the thing down, so it can't react quick to the compressor. It is even one of the self tests performed by the computer when you read the codes, and there is a code saying that the solenoid can't raise the idle enough, a sure sign that the idle is either mis-set or, more likley, the solenoid is gummed up.

Properly cleaned and adjusted, you should barely notice the idle move as the ac compressor cycles on and off. I'm running GT40 heads and an E303 cam, which means a lumpier idle than stock, but when the bypass is clean, the idle hardly moves when the ac kicks on. It does get a bit sensitive and raggity when air temps go above 95, but even then it works OK.
 
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WICKED50LTR

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Aug 28, 2002
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Jul 18, 2005
#4
  • Jul 18, 2005
  • #4
even when the car doesnt have the a/c on?? the car runs great... ill try and clean it and see what happens
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Jul 18, 2005
#5
  • Jul 18, 2005
  • #5
Sam is spot on, as usual.

Here is some info on doing this. I would follow each step (page), so you can reset or at least check each item in the idle setting, as each affects one another.

Good luck.
 
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WICKED50LTR

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Aug 28, 2002
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Jul 24, 2005
#6
  • Jul 24, 2005
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ok i give up, sprayed the sucker down, took the IAC off and she worked fine for about 3-4 hrs then she started acting up again. sprayed this thing clean with GUMOUT. any other ideas??
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Jul 24, 2005
#7
  • Jul 24, 2005
  • #7
Just to confirm, you do have the idle setting adjusted so that on a warm idle, with no accessories on, the car will idle with the IAC disconnected, right?

Or perhaps the pintle in the IAC is too filty and needs more vigorous cleaning?

Good luck.
 
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WICKED50LTR

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Aug 28, 2002
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Jul 24, 2005
#8
  • Jul 24, 2005
  • #8
yea she can run fine with the IAC disconnected. I dont know how much more i can clean this thing, 2 bottles of GUMMOUT? maybe its time for a 3rd.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
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Jul 24, 2005
#9
  • Jul 24, 2005
  • #9
Or let it soak. Or just get a new IAC.

Did you happen to disconnect the battery after doing all that the first time? It would seem coincidental that this would crop up after 3-4 hours - perhaps how long it takes to fully adapt to learned settings with the A/C on.

How is the cold idle? If that sucks too, The IAC is not up to par. Some folks have had luck with the bypass plate (there is more info on all of this in Jrichker's sticky at the top of the sub-forum page).
My two cents.
Good luck bud.
 

86T-Top

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Jun 29, 2001
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Dublin, PA
Jul 24, 2005
#10
  • Jul 24, 2005
  • #10
Did you take the IAC apart when you cleaned it? There are two screws that hold the two halfs of the IAC together, you must take it apart to get it completly clean and use q-tips to get the carbon out. I only ask b/c that site with instructions to clean the IAC doesn't mention this.

Also what do you have your idle set at when the car is warm and no accesories on? I found that I need to keep mine around 800 RPM, b/c of the E cam. Also, when was the last time you gave her a tune up? As dumb as that may sound a worn cap, rotor, or plugs can cause a crappy idle, but I doubt that is your problem.

Mario
 

amplifier28

Member
Apr 16, 2005
222
1
19
Jul 25, 2005
#11
  • Jul 25, 2005
  • #11
Is it o.k. to clean the mass air meter with a q-tip and carb cleaner? Or do I have to use some type of electrical spray cleaner?
 

jrichker

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Jul 25, 2005
#12
  • Jul 25, 2005
  • #12
To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.
 

Dbeck002

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Apr 30, 2005
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South florida
Jul 25, 2005
#13
  • Jul 25, 2005
  • #13
Dude it could be your voltage being so low, when you turn the AC on it probably uses up all your electrical power and the car cant run... Check for corroded cables and charge at idle w/o AC.
 
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WICKED50LTR

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Jul 26, 2005
#14
  • Jul 26, 2005
  • #14
when i replaced the Alternator with the 130amp i replaced all wires. im gonna try it one more time this weekend, if not. I only got about 2 more months of complaining to do before the Fall comes
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
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Arkansas
Jul 27, 2005
#15
  • Jul 27, 2005
  • #15
I'm having a problem just like this all of a sudden. The car does an engine breaking type sensation when I come to a stop after being in neutral (or pushing in the clutch) the car dies on me Makes me pretty upset. I cleaned the IAC/disconnected the battery...and it is doing a bit better but it is still surging After a couple more drives I'll see what happens.

It is a bit worse when the a/c is on...

Idle is at 750rpm.
 

Dbeck002

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Apr 30, 2005
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Jul 27, 2005
#16
  • Jul 27, 2005
  • #16
You guys probably have some killer vacuum leaks somewhere... Mine used to do that.

Do this test though. Take the belt off and turn the key on engine off with the AC on. youll hear the clutch on the AC compressor engage, try to rotate the pump. If its impossible or really hard than thats the problem.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
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Jul 27, 2005
#17
  • Jul 27, 2005
  • #17
dbeck002 - I don't think I have a vacuum leak.

Are you talking about the water pump?
 
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WICKED50LTR

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Aug 28, 2002
257
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Central NJ
Jul 29, 2005
#18
  • Jul 29, 2005
  • #18
ok tried it again, took everything off, cleaned it all. IAC and the TB. unplugged the battery for 30 min, put it back together with the plug off the IAC. Ran her for a bit and she was ok, put the plug back on the IAC, went for a ride with the A/C on with no other acc. on. got about 10 miles and then she stalled at a light. Im goin to buy a new IAC today and try that. Im really starting to give up.
 

crazypete

All my crevices are greased.
Oct 22, 2004
930
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18
Arlington, MA
Jul 29, 2005
#19
  • Jul 29, 2005
  • #19
Go to the back of the throttle body where the throttle cable hooks to the paddle and look for the adjustment screw. Start the motor and turn the screw in till it idles 1000-1100. This is the endall fix for idle problems. You'll never be bothered by silly AC and worn out PS pumps dragging again or gummed IAC. Plus it takes all of 1 minute and you can undo it just as easy if it doesnt work for you.
 

fivespeedsteed

20+ Year Stangneter
Oct 17, 2003
748
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Richmond, VA
Jul 29, 2005
#20
  • Jul 29, 2005
  • #20
AmMscl said:
Might want to try to clean T-body or idle air solenoid
Click to expand...


same thing happened to my car and that fixed it. i made this pic a while ago of my engine when someone asked the same thing so here it is.



the two red dots are the bolts that hold it on, so unscrew those, then pull off the cylender looking thing and clean it all out with throttle body cleaner. hope i helped. oh and the red dot on top is the throttle postion sensor. this made my car run great, it idled higher with the ac on and cold startups are a joke.
 
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