For some reason, when I am driving...

If I floor it, the ac cuts off. When I get to 55mph it stops working...

What's the deal?

 

engine management system working and trying to give you maximum HP
WOT - that seems right
just being above 55MPH and cut out, that seems wrong

 

Are you sure it's not just being rerouted to the Defrost register? That can happen when there is a vacuum leak or a bad check valve in the vac reservoir.

 

Yeah, it's supposed to cut out at WOT. Unless you're flooring it above 55, I have no explanation.

 

the a/c is supposed to cut off at WOT, dont know about the 55 part though

 

darn, posted way too late

 

i never had it do this before...

never cut out before, that i recall...

but getting no ac at 55mph+ sucks!

 

It ALWAYS cut out at WOT -- thats the way they're made. Whether you ever noticed it or not, I can't say why -- but that's how the vehicle is set up.

 

thats what the windows are for

 

Pushing those big tires with a 3.0L could easily be letting your A/C control vacuum drop too low at 55+ MPH. Put the blower fan on high and listen to the Defroster register when it happens.

 

my dad's crown vic does the exact same thing... its a vac leak somewhere and it sends the air to the defrosters

 

I'd put money on low vacuum as well. It isn't cutting off, it is just coming out the defroster vents and you don't feel it or notice it.

 

What vechile?

 

At WOT the driver is asking the engine for the most available torque and for the engine management system to be able to supply the driver with that demand, the a/c compressor is torned off to decrease the load on the engine, therefor freeing up more usable power at WOT.

 

ok.

so, what do i have to fix to get it working right, again?

because for the last 45,000+ miles i have not had this problem...

 

Is it coming from the defroster vents or not?

 

hmmm...

i think it might have been...

i noticed a "defrosting" distortion on the glass this morning...

ya know what i am talking about?

diff. temps meeting at the window.. blurring like heat does(but it was cold ac)

 

If you can verify that it is shifting to the defroster when you get into the throttle, then you know that the A/C control vacuum is dropping when the engine vacuum drops. This is not supposed to happen.

If it does, it probably means that you either have a vacuum leak somewhere from the vacuum reservoir to the AC servo diaphragms or the check valve in the reservoir is not working.

 

I had a vac line off that goes by the passenger spark plugs on mine...

 

DOH! I didn't even think of a vacuum problem forcing the air directors to shift...and that came up on the board just recently also.

 

Dingo!



I told him, when he called me , that it sounded like a vac leak.. Who knows, its wierd.



P.S. This guy next to me in class stinks.

 

Oh Christian! Did you hear what I said to you when you called Leo that night?

 

wind at 55 mph should feel pretty good! why use the ac?

 

Wind at 55mph when it is 100 degrees outside just feels like you're in a high powered convection over with a fan boosters.

 

ok.

it does re-route to the defrost...

so, what do i need to look at to fix this?