Slight A/C problem... or normal?

[Motorhead350]

After the vans first tour it held up fine, except for one thing: The A/C will turn off when I am giving it hard throttle. Such as on ramps, overtaking or up hill. Soon as I am off the throttle the A/C kicks back on. It's as if the A/C compressor is kicking off. It's fine blow 1/3 throttle, anything above that, it shuts off.

Is this normal, do I have a vacuum leak or does it need more freon? It had ZERO when I got it. It has 48ozs in it and takes 55.

I will post this on the Econoline message board when my membership is approved, but if anyone knows right now... thank you in advance!

[tbone]

Vac leak. Ounces not pounds.

[Motorhead350]

Vac leak. Ounces not pounds.

Thanks!

Any idea where to search because this only effects the A/C? Anything common?

[fastblackmerc]

Could be normal.

[yjmud]

Normal
Wot shut off

[Mebot]

Normal
Wot shut off
For a van? Thought that was a perk for Marauders only...

[Motorhead350]

Yup. Apparently, this van goes into "defrost mode" for it's towing feature. This is normal. Nothing is broken.

Another day, another lesion learned.

[fastblackmerc]

For a van? Thought that was a perk for Marauders only...

Most cars do this.

[Spectragod]

My E series vans did the same thing.

[martyo]

Yup. Apparently, this van goes into "defrost mode" for it's towing feature. This is normal. Nothing is broken.

Another day, another lesion learned.


Most cars do this.


My E series vans did the same thing.

My 1992 Caddy STS does this - it is very noticeable because I run the AC on the "ICEBOX" setting but when I get on the on ramp or pass one of the Real Housewives of Atlanta who is fixing he make up while she drives, the AC cycles down.

Bottom line is it is nermal. :P

[RF Overlord]

Bottom line is it is nermal. No, this is Nermal:http://img2.wikia.nocookie.net/__cb20140219181443/garfield/images/5/57/Nermal.gif

[J-MAN]

Sounds like your normal.................Never thought I'd say that. :depress:

[martyo]

No, this is Nermal:http://img2.wikia.nocookie.net/__cb20140219181443/garfield/images/5/57/Nermal.gif

You always have to one up me! :banned:

[EMAS]

"Defrost mode" is the default duct mode required by law as that is considered mission critical. The WOT cut out only operates at WOT as it sounds like.

So if it goes to defrost when you are on the throttle you have a vacuum leak somewhere as there should be enough vacuum at anything less than WOT. There should be a reservoir somewhere and likely a check valve too so the mode stays where it is commanded even with some WOT.

[Motorhead350]

It takes at least 1/3 to 1/2 throttle to go into defrost mode. City driving and highway cruising is fine.

Is this still something to be concerned about? I can deal with it. Almost not worth the trouble to me.

[EMAS]

It takes at least 1/3 to 1/2 throttle to go into defrost mode. City driving and highway cruising is fine.

Is this still something to be concerned about? I can deal with it. Almost not worth the trouble to me.

You've definitely got a vacuum leak in the HVAC hoses or control then, if it doesn't bother you then roll with it until it gets to the point where it does bother you.

[Wags]

Dominick,

You said it takes 55oz of refrigerant. That seems high unless you have rear aux ac also. If you don't and you are overcharged you are probably hitting a max high pressure condition when engine rpms go up. When it hits the max pressure the compressor will switch off until the high pressure drops below a certain point. There is a high pressure and low pressure sensor in the system. It is not the wot condition as you said it is dropping out at lower throttle positions. And if it is too low on refrigerant it will switch on and off also. Does the compressor cycle frequently at idle? If so, that can indicate a low refrigerant condition.

Wags

[tbone]

My 95 Chevy van had a similar problem. It was a vac leak in the mechanism that controls where the air comes out of. Similar to a revolver chamber.

[EMAS]

Dominick,

You said it takes 55oz of refrigerant. That seems high unless you have rear aux ac also. If you don't and you are overcharged you are probably hitting a max high pressure condition when engine rpms go up. When it hits the max pressure the compressor will switch off until the high pressure drops below a certain point. There is a high pressure and low pressure sensor in the system. It is not the wot condition as you said it is dropping out at lower throttle positions. And if it is too low on refrigerant it will switch on and off also. Does the compressor cycle frequently at idle? If so, that can indicate a low refrigerant condition.

Wags

Upon further description of the problem the air stays cold the mode door just goes to the default defrost position because there is a vacuum leak.

[Wags]

Ok. According to the original post he said that the ac was "turning off" at higher rpms, but not at wot. I thought he had 2 separate issues going on (compressor switching off and blend door problem) One other thing, if it was completely down on refrigerant, don't expect it to stay full now. It's a sealed system and if it was empty, it had to leak from somewhere. Guess I don't speak "Domish";).

Wags

[EMAS]

Guess I don't speak "Domish";).

Wags

It is hard to pick up that is for sure.

[Motorhead350]

Ok, today it was not 100 outside and the A/C stayed on better. Plus, the engine temperature was a little lower. I am starting to think this was weather related, not an actual "issue", but again, I am uncertain.

I will check it the best I can soon with the carburetor cleaner trick. Even if I have to remove the dog house.

[EMAS]

It is possible that it is in the hose leading from the engine to under the dash. However it is more likely that it is likely in the dash, either in the control panel, the hoses or the vacuum motors.