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BuckeyeSRT 07-14-2014 07:16 AM

HVAC (AC) after hard acceleration
 
I just tried a search (blower) to see if anyone else has even had this problem and did not see so if I missed a thread please point me there.
AC on Auto and hammered my '12 Hemi (love to hear the intake). As soon as I slow down I notice cold air coming out of the vents but not with great speed. So I lowered the desired temp thinking that would increase the velocity of air. That did not help, so I turned the fan dial all the way to max speed. I got a lot of fan noise (like it was blowing harder) under the glove box but no increase out of the dash vents. Then I switched from Auto over to dash vents alone with the fan speed on max. No increase in air flow but same blower noise in the front passenger foot well. I went with the Jeep CTRL + ALT + DELETE ( shut her off and restart) and it was back to normal operation. I have never had that happen before. Anyone?

Angler 07-14-2014 06:09 PM

Re: HVAC (AC) after hard acceleration
 
Haven't had that happen, Buckeye. If it happens again I would also try turning on the recirculate setting to see if that affects the air output.

silvermax04 07-14-2014 06:17 PM

Re: HVAC (AC) after hard acceleration
 
If it keeps doing it try the full reboot aka battery cable disconnect and reconnect. Solves many electrical gremlins

f1anatic 07-14-2014 06:48 PM

Re: HVAC (AC) after hard acceleration
 
Quote:

Originally Posted by BuckeyeSRT (Post 1051139)
I just tried a search (blower) to see if anyone else has even had this problem and did not see so if I missed a thread please point me there.
AC on Auto and hammered my '12 Hemi (love to hear the intake). As soon as I slow down I notice cold air coming out of the vents but not with great speed. So I lowered the desired temp thinking that would increase the velocity of air. That did not help, so I turned the fan dial all the way to max speed. I got a lot of fan noise (like it was blowing harder) under the glove box but no increase out of the dash vents. Then I switched from Auto over to dash vents alone with the fan speed on max. No increase in air flow but same blower noise in the front passenger foot well. I went with the Jeep CTRL + ALT + DELETE ( shut her off and restart) and it was back to normal operation. I have never had that happen before. Anyone?

I think you ought to read up on the functionality of A/C compressor in modern cars:
1) The A/C Compressor shuts down at WOT (Wide Open Throttle)
2) If engine temperature is elevated, the A/C compressor will not operate in order to protect the engine from further overheating.
3) Depending on the temperature and humidity outside, the A/C compressor will also shut off also because the same engine temperature considerations.

It is normal behavior. If this happened in bumper-to-bumper traffic, it would be different.

BuckeyeSRT 07-14-2014 08:27 PM

Re: HVAC (AC) after hard acceleration
 
Great info but the engine temp was not elevated post WOT that is why I was concerned it happened. Post WOT I traveled approx 7 miles at about 50 mph with no traffic


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f1anatic 07-15-2014 06:24 AM

Re: HVAC (AC) after hard acceleration
 
3 Attachment(s)
Unless you are looking at the digital values, obtained via an OBD-2 reader, you will not know what is elevated or not. I have one for the Subaru Legacy (via the CAR-PC) and I always keep an eye on a few parameters, including coolant temperature (boost, AFR, knock, air flow, IAT). The analog gauge on the dashboard never registers a change, but the temperatures can range between 74 C (cruising, no load, cool evening) and as much as 96 degrees Celsius (A/C on, stationary, bumper-to-bumper traffic, hot outside) (165 F to 205 F).

Moreover, to the untrained eye, the analog gauge in my Forester and that in my Legacy show the same temperature but I have a GrimmSpeed 160 Degree Thermostat in the Legacy (turbocharged) vs. the standard 180 in the Forester.

Unless I read numbers, I do not trust the temperature gauge in most cars. It is a relative value, and when it dives in the red band, it might be too late. Those pictures are before my Stage 3 and cooler T-stat...so that is the old 180 deg F thermostat.

Here's the dash 2 months ago, with the 160 deg. T-stat.

You'd think I took other pictures since...but I have no idea where they are...The interface is the same, despite several CAR-PC builds since. 85 is the coolant temperature in Celsius (185 deg F), the engine temp gauge is in the middle. I will take some today.

BuckeyeSRT 07-15-2014 07:18 AM

Re: HVAC (AC) after hard acceleration
 
Quote:

Originally Posted by f1anatic (Post 1051567)
Unless you are looking at the digital values, obtained via an OBD-2 reader, you will not know what is elevated or not. I have one for the Subaru Legacy (via the CAR-PC) and I always keep an eye on a few parameters, including coolant temperature (boost, AFR, knock, air flow, IAT). The analog gauge on the dashboard never registers a change, but the temperatures can range between 74 C (cruising, no load, cool evening) and as much as 96 degrees Celsius (A/C on, stationary, bumper-to-bumper traffic, hot outside) (165 F to 205 F).

Moreover, to the untrained eye, the analog gauge in my Forester and that in my Legacy show the same temperature but I have a GrimmSpeed 160 Degree Thermostat in the Legacy (turbocharged) vs. the standard 180 in the Forester.

Unless I read numbers, I do not trust the temperature gauge in most cars. It is a relative value, and when it dives in the red band, it might be too late. Those pictures are before my Stage 3 and cooler T-stat...so that is the old 180 deg F thermostat.

Here's the dash 2 months ago, with the 160 deg. T-stat.

You'd think I took other pictures since...but I have no idea where they are...The interface is the same, despite several CAR-PC builds since. 85 is the coolant temperature in Celsius (185 deg F), the engine temp gauge is in the middle. I will take some today.

Look man, I'm not looking for an argument. I'm looking for some help.
Do you own a WK2? If you did you would know that with a couple of buttons on the wheel pressed you can get the exact temp of the coolant, the oil pressure, trans temp etc. Read this part carefully (again). My Jeep was not at en elevated temp. It was below 200. Thank you again for your attempt, if you have had a similar experience or have a suggested fix (beyond your car was too hot and I need to learn more about an AC compressor) I'm all ears or eyes.:thumbsup:

Frango100 07-15-2014 07:18 AM

Re: HVAC (AC) after hard acceleration
 
I can be wrong, but eventhough its true that the compressor will be switched off for some conditions, the problem here seems to be the airflow from the vents. This should not have to do anything with the AC compressor switching on or not. A recirculation door in a wrong position could make more sense. Next time i would try switching the recirculation button.

BuckeyeSRT 07-15-2014 07:19 AM

Re: HVAC (AC) after hard acceleration
 
Quote:

Originally Posted by Angler (Post 1051399)
Haven't had that happen, Buckeye. If it happens again I would also try turning on the recirculate setting to see if that affects the air output.

I thought of this same thing after. My issue reminded me of the blend-door issue Ford had with the F150/Expedition years ago.

f1anatic 07-15-2014 01:58 PM

Re: HVAC (AC) after hard acceleration
 
1 Attachment(s)
Quote:

Originally Posted by BuckeyeSRT (Post 1051578)
Look man, I'm not looking for an argument. I'm looking for some help.
Do you own a WK2? If you did you would know that with a couple of buttons on the wheel pressed you can get the exact temp of the coolant, the oil pressure, trans temp etc. Read this part carefully (again). My Jeep was not at en elevated temp. It was below 200.

And what I am telling you is that unless you know the value of your coolant temperature, the analog gauge is not a good indicator. For all I know, your fan relay is acting up. At WOT the A/C compressor got disconnected and the fan stopped blowing. Upon return to normal driving, the fan did not re-engage at the speed that had been programmed. Or the key to the whole thing is that you had it in Auto. If in Auto, the car will do what it thinks is best for the whole system, which is not always the best for your own comfort.

What is a WK2 and how do I get one ?

BuckeyeSRT 07-15-2014 02:15 PM

Re: HVAC (AC) after hard acceleration
 
Quote:

Originally Posted by f1anatic (Post 1051708)
And what I am telling you is that unless you know the value of your coolant temperature, the analog gauge is not a good indicator. For all I know, your fan relay is acting up. At WOT the A/C compressor got disconnected and the fan stopped blowing. Upon return to normal driving, the fan did not re-engage at the speed that had been programmed. Or the key to the whole thing is that you had it in Auto. If in Auto, the car will do what it thinks is best for the whole system, which is not always the best for your own comfort.

What is a WK2 and how do I get one ?

LOL
Uncle, I give up :)

lstowell 07-15-2014 05:15 PM

Re: HVAC (AC) after hard acceleration
 
Quote:

Originally Posted by Frango100 (Post 1051579)
I can be wrong, but eventhough its true that the compressor will be switched off for some conditions, the problem here seems to be the airflow from the vents. This should not have to do anything with the AC compressor switching on or not. A recirculation door in a wrong position could make more sense. Next time i would try switching the recirculation button.

That, a door in the wrong position, would be my guess as well.

Just possibly under WOT, all the electrons, not having their seat belts fastened, headed for the rear of the Jeep, and the door controls went wonky.

I've WOT'd a 5.7 '14 many many times in temperatures even horny toads, gila monsters, and camels won't tolerate and never had this happen.

If it hadn't reset, I'd suspect something coming a bit loose. Since it reset, I'd have to go with "sunspots" but it is something I'd keep an eye on just in case.


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