A/C cuts off when hard acceleration

[WanderLoveJosh]

So I've noticed this before, back when I first hit the road driving through the blue ridge mountains. When accelerating up hills the ac would cut out, and if I let off the gas a little bit it would come back. I noticed this yesterday when I took the trailer out for the first time. Why would the ac cut out when I have to press the pedal hard to accelerate??

 

[jonsun]

the compressor cuts out or the interior blower motor? The compressors clutch is designed to disengage under hard acceleration to give you more power. It also helps fuel economy. If you mean the interior blower it can be a few different things. They have a resistor next to them that can go bad. Or there's a short somewhere.

or you might have a vacuum leak starting to form.

 

[WanderLoveJosh]

I don't know what is what, so essentially air stops coming out of the vents, then when I let off a little it will start blowing again, this only happens when having to go up a long hill, or at a dead stop trying to get up a hill.

 

[jonsun]

It didnt always do this, right? does the blower motor sound like its slowing down or stopping?

what make, model, year, and mileage?


there's a few things to understand. when under load the manifold vacuum drops very low. the vent selection is controlled by this vacuum. 2. blowers have a replaceable resistor if the voltage gets too high it might be turning the blower off. 3...going out on a limb but it might supposed to do this. designed to cut off electrical and crank load under throttle for fuel mileage.

lets see what others say

 

[ZoNiE]

The compressor cuts out at a certain RPM to prevent over pressurization. somewhere in the 3500 and higher range, depending on the make and model. The newer R134A systems cut out a a much lower RPM than the older R12 due to the higher pressures in the newer systems. If this is happening, it is normal.

 

[tx2sturgis]

Sounds like a drop in vacuum and a blend door is closing. But some vehicles do cut the compressor out during hard acceleration.

Like Bardo, I would ask what is the year, mileage, make and model...otherwise we are totally guessing...

How often are you needing 'hard acceleration'?

 

[highdesertranger]

I vote the loss of vacuum, common problem. you either have a vacuum leak or a check valve is bad. highdesertranger

 

[WanderLoveJosh]

Idk if it's always done it or not, I only noticed it while driving through hills on the east coast last year, it's only big long hills where I need to accelerate more to get up. And it was kinda warm yesterday so I turned on the ac and noticed it while roaming the trailer to the campground and thought I should maybe see if this is normal or not. It's a 2000 ford e150 conversion van.

 

[highdesertranger]

I know it's warm but see if it does the same thing with the heater and defroster. highdesertranger

 

[Gideon33w]

Smoke test

 

[Tomcor]

I have the same van and same problem. Has to do with vacuum canister or check valve.

http://sparkys-answers.com/2014/11/1999-ford-e150-air-only-blows-out.html

 

[travlinman and wife]

I have a 2000 f150 it does the same thing and has for 4 years expect it does not stop blowing instead it blows out the defrost but does not affect runing

 

[WanderLoveJosh]

I know it's warm but see if it does the same thing with the heater and defroster.  highdesertranger

Its def doing it the same with the heater, being out here in colorado, and even driving unhooked from trailer, it def does it.

 

[highdesertranger]

it's for sure a vacuum problem. either you have a leak from a rotten or broken hose, or a check valve is bad or a bad switch or a bad servo. find the vacuum reserve canister with the run the engine and turn it off. unplug the hose that feeds the cab interior at the canister, you should hear a woosh. if you don't the leak is from the canister to the engine. if you do the leak is between the canister and the blend doors. the 2 most common locations are at the firewall where the hose(s) pass through or the switch itself. highdesertranger

 

[travlinman and wife]

I have a2000 f150 that does that and has for the last 100,000 miles. but this one does not shut off it switches to the defrost vents and switches back when the hard pull is over.

 

[WanderLoveJosh]

I have a2000 f150 that does that and has for the last 100,000 miles. but this one does not shut off it switches to the defrost vents and switches back when the hard pull is over.

I'll have to check next time I drive, and see if mine comes out the defrost, i've never thought to check that.

 

[Bohemian scout]

My van started doing this on a trip west late May at approx 135000 miles. I just had an isolator and agm auxiliary battery installed. I had all the hoses and connections checked. It's a 2006 ford econoline 150 van. When accelerating the fan switches from blowing out the vent to blowing out the defrost on windshield. I can also feel air at my feet. If I take my foot off the gas it switches back. Drives me crazy!!!

 

[highdesertranger]

vacuum leak. highdesertranger

 

[Ticklebellly]

When accelerating up hills the ac would cut out, and if I let off the gas a little bit it would come back.

Normal operation in four of the cars or campervans I have had in the last couple of years.    Owner's manual says the engine management system does this when accelerator is pressed hard to stop the power robbed by the AC compressor because you obviously need (or want) all the power you can get right now.

 

[MikeRuth]

Definitely vacuum and my 2007 E-150 does the same thing, only problem, mine can is under the DASH!

I have temporarily added a vacuum pump to the system and switch it on from in the cab. I wish my can was out side oh how I wish.

Not looking forward to tearing the dash out