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A/C charged...now a new problem

  • Thread starter Thread starter cobra2798
  • Start date Start date Jun 17, 2009

cobra2798

New Member
Mar 30, 2005
303
2
0
Clermont, Florida
Jun 17, 2009
#1
  • Jun 17, 2009
  • #1
So I took my A/C in to get looked at, could not find any leaks and the system checked out ok. They recharged the system and now it works great but there is a problem. With the A/C on the car is idling around 1,100-1,200rpm's, with it off it idles fine.....850-900rpm's. What is the problem here or is this normal?
 

jeremy canter

Member
Dec 2, 2008
402
0
17
Orange County , NY
Jun 17, 2009
#2
  • Jun 17, 2009
  • #2
your car is fine it just needs the extra RPM TO HELP TURN THE ALT FOR YOUR BLOWER AND THE POWER TO TURN THE A/C > DON'T SWEAT IT > JUST ENJOY IT
 

cobra2798

New Member
Mar 30, 2005
303
2
0
Clermont, Florida
Jun 17, 2009
#3
  • Jun 17, 2009
  • #3
jeremy canter said:
your car is fine it just needs the extra RPM TO HELP TURN THE ALT FOR YOUR BLOWER AND THE POWER TO TURN THE A/C > DON'T SWEAT IT > JUST ENJOY IT
Click to expand...

Great, thanks
 

Gearbanger 101

Straight Outta Locash
20+ Year Stangneter
Aug 10, 2002
9,457
1,377
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Ontario, Canada
Jun 17, 2009
#4
  • Jun 17, 2009
  • #4
As stated above....a couple hundred extra RPM is perfectly normal when the A/C is engauged.

Keep in mind, when your A/C comes on, it also kicks your electric fan into high gear. That draws additional current, which is why the engine speeds up to compensate.
 

bhuff30

Founding Member
Dec 11, 2001
6,037
35
129
Olathe KS
Jun 18, 2009
#5
  • Jun 18, 2009
  • #5
Really, you need to run a V8 at 1100-1200rpm just to turn the AC?

My 97 idles around 850-900with the AC on and only slightly lower with the AC off. Even my mom and sisters V6 mustangs don't break 1000rpm at idle with the AC on full blast. Your cobra may be programmed that way, but seems odd to me.
 

Gearbanger 101

Straight Outta Locash
20+ Year Stangneter
Aug 10, 2002
9,457
1,377
234
Ontario, Canada
Jun 18, 2009
#6
  • Jun 18, 2009
  • #6
bhuff30 said:
Really, you need to run a V8 at 1100-1200rpm just to turn the AC?

My 97 idles around 850-900with the AC on and only slightly lower with the AC off. Even my mom and sisters V6 mustangs don't break 1000rpm at idle with the AC on full blast. Your cobra may be programmed that way, but seems odd to me.
Click to expand...

You speak as though anyone should put any kind of faith into what the stock Tach says?
 
4

40oz

Member
Jan 9, 2006
499
3
18
Minneapolis
Jun 19, 2009
#7
  • Jun 19, 2009
  • #7
for the record, I was noticing today that my 03 5-speed GT idles at pretty much the same rpm with AC on or off. I'm not going to go out and look, but it was under 1000 rpms, I'd guess ~750-800 or so. Point is that it shouldn't idle over 1000 when the car is warm, AC on or off, IMHO. But it's probably something stupid and cheap, whatever it is.

Don't ask me why I was looking at the tach for that today or why I checked this thread tonight, I'm just saying
 

the98stang

Active Member
Aug 12, 2005
2,408
0
47
Clovis, CA
Jun 19, 2009
#8
  • Jun 19, 2009
  • #8
40oz said:
for the record, I was noticing today that my 03 5-speed GT idles at pretty much the same rpm with AC on or off. I'm not going to go out and look, but it was under 1000 rpms, I'd guess ~750-800 or so. Point is that it shouldn't idle over 1000 when the car is warm, AC on or off, IMHO. But it's probably something stupid and cheap, whatever it is.

Don't ask me why I was looking at the tach for that today or why I checked this thread tonight, I'm just saying
Click to expand...

1200rpm with the AC on is OK....if you have a blower
 

1987stangman

Member
Jul 12, 2006
684
24
19
Jun 20, 2009
#9
  • Jun 20, 2009
  • #9
bhuff30 said:
Really, you need to run a V8 at 1100-1200rpm just to turn the AC?

My 97 idles around 850-900with the AC on and only slightly lower with the AC off. Even my mom and sisters V6 mustangs don't break 1000rpm at idle with the AC on full blast. Your cobra may be programmed that way, but seems odd to me.
Click to expand...

+1 for that, I just replaced nearly everything under the hood A/C related and mine idles around 900 with the ac on. Even my Fox idles under 1000K with on.

I guess you need to look at the bigger picture. I'm gonna guess you took your car in because it was blowing warm, or just not keeping up? If it needed a re-charge, then u have a leak somewhere. Also, does the RPM drop when the compressor cycles (stops), and then goes up when it starts?
 

AdRock

Member
Nov 13, 2003
521
1
19
South Texas
Jun 22, 2009
#10
  • Jun 22, 2009
  • #10
I have my idle set at 820 with the Diablo and it'll bump up to 1k when the A/C kicks on.
 
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