Ac wont blow when accelerating!!

It's not supposed to.

Modern cars have a WOT cutout which shuts the A/C off at a certain percentage of WOT...usually 80% or 90%. It gives that car all it's available power.

If you don't want it to do that, stop flooring it :)
 
Mike is right on. most of the time it stays cut off for 5-20 seconds or so after the WOT run is done (cant recall which spec is for which car; I think stangs are on the quicker side) - and since cold air continues to flow with the A/C compressor not running (try switching from A/C to vent sometime - cold air continues for 30-60 seconds), most folks dont notice.
 
Mustang5L5 said:
It's not supposed to.

Modern cars have a WOT cutout which shuts the A/C off at a certain percentage of WOT...usually 80% or 90%. It gives that car all it's available power.

If you don't want it to do that, stop flooring it :)
What you say is true but it will not cause the air to blow out the defrost.



Sounds more like a vacume problem to me. Seen it plenty of times. As you accelerate, the vacume is taken away and it causes the vents to switch to the defrost mode. Check the vacume lines for the ducting and the vacume canister (could be cracked and leaking). Also seen the vacume switching valve in the dash go bad as well. Se if you can hear a vacume leak in the dash area.
 
PRO50SC said:
What you say is true but it will not cause the air to blow out the defrost.


Mine did...in my 5.0 that is.


Everytime i would go WOT with the A/C on (when i had it) the air would stop blowing out of the registers and instead blow out of the defroster and floor vents.
 
Mustang5L5 said:
Mine did...in my 5.0 that is.


Everytime i would go WOT with the A/C on (when i had it) the air would stop blowing out of the registers and instead blow out of the defroster and floor vents.
Then you also had a vacume leak that apparently you didin't know about. Did you ever trace down the cause? Because of design, it is physically impossible for the problem to be caused by anything else at wot. The venting system is operated by vacume and vacume only.
 
jstang209 said:
im not flooring it.. when im normally driving, everything my foot is on the gas it the air is not blowing.. intil i let my foot off the gas.. or barley pressin the petal
It can also happen under normal driving conditions. Like I said, check all the vacume lines that operate the ducting controls. I bet there is a leak somewhere.
 
The issue is the reservoir. It sits in the passenger side fender. If you follow the source vacuum from the tree, it comes to a three-way check valve on the passenger side of the firewall. One line goes into the cabin (the source for your controls), while the other goes to the reservoir. There is a leak somewhere.
 
You are simply running out of vacuum. Put a vacuum guage on the intake manifold vacuum port and see if it doesn't go to zero every time yor a/c goes to defrost on acceleration. Your vacuum tank is not holding or is too small.