Okay for some reason I cant find any threads regarding this issue, I do know that they exist but I must be using wrong keywords or something. Anyways I was driving the car all day and decided to use the A/C but its not getting cold. Tried the A/C when the car is stone cold the next morning and it works.

One obvious conclusion, Pettit duct doesnt have a way to have airflow going to the cylinder thing(forgot what its called) so driving all day my hot engine bay kept it hot. Those of you with upgraded SMICs what did you do to get airflow back to it? I really want my A/C as its starting to get hot.

One last problem I found when I was testing for A/C was looking at the commander of my Power FC fan speed 1,2 and 4 work. Fan speed 3 has the A/C switch on the sensor screen going on and off as well as my Idle fluctuating, other speeds are fine. Im guessing the infamous messed up ground?

 

I doubt that's it. No aftermarket ducts have that and everybody's AC still works.

 

dude, that's not how AC works....the basic refrigeration principal is the more heat your remove, the more heat you can absorb. the condenser is the heat exchanger in the cycle, it looks like a radiator, but isn't. it sits in front of your radiator. it has nothing to do with that "cylinder" thing you're talking about, that's just the sight glass and filer drier.

and if all you're running is just an upgraded SMIC with a duct, you should not be restricting any air going to the condenser.

there is a common problem associated with the PFC not allowing you do get all the fan speeds. there is a write up on it in the PFC section of this forum...IIRC it has something to do with the grounds.

 

My A/C worked 100% before I installed the pettit duct and the bigger intercooler, even with my Power FC. My A/C is working now even idling in my garage. Just wasnt working when I was driving around for a hour or two. Im not sure whats up. In the garage its blowing cold on 1,2 and 4. Number 3 is shutting it off and on.

 

it could just be the pressure switch, the AC switch, or the numerous other switches associated with the AC system, ie the compressor clutch. The refrigerant could be low causing the pressure switch to trip.

just a couple things you could check

 

I installed a smic a few weeks ago and fabricated my own duct out of fiberglass. My AC is still blowing cold as a bitch

 

+1 that you have two separate issues. Fix them one at a time.

+1 that the cylinder thingy is the receiver dryer and has nothing to do with your A/C blowing cold air. +1 that for this (cold air) to happen air must blow across the condenser, that is the thing that looks like a second radiator in front of your engine's radiator. I'm assuming that this is an airflow problem and not one of the other issues that tt7hvn mentioned. Well, let's start with one thing, eliminate it and move on to the next.

You mentioned that your A/C works when the car is stone cold but not when it's hot? This hints that the condenser doesn't have air flow. Let's start with this. Find the compressor, start the car and check out what compressor's clutch looks like when it's not spinning. Turn the A/C on and check out what the compressor clutch looks like when it's engaged and spinning. Now, when the compressor is engaged, are the radiator cooling fans spinning? Both of them? If not, there's your problem.

You might also check to see if there is air flow from the back of the radiator to the front when the fans are blowing. I've seen aftermarket stuff (radiator, smic, etc.) create a path for warm air to return to the front of the radiator (and condenser) causing the A/C to be ineffective. A good hint that this is the case is that the A/C is warm in heavy traffic but cold at highway speeds.

Post back and let us know what you find.

 

+1 for an electrical issue. Either you snapped a brittle wire or disconnected a pressure switch when doing the install.

 

I will check those issues. Where's the pressure switch?

 

someone will probably chime in with the exact location but I recall it being a few inches off of one of the receiver dryer lines

 

Yep, the pressure switch is a 2-wire switch on one of the thin aluminum lines coming from the drier. Stock it's under the battery tray right along the frame rail.

Dale

 

If the AC only works on several fan speed settings its usually an issue with the ecu not seeing the ground and turning on the compressor. Its notorious to happen with the power fc. Search pfc ac fix. It involves adding in a relay. The intercooler duct has nothing to do with the ac. Like said above, you have another problem.

 

Mazda put the receiver/drier in the duct because the hot air coming off the back of the radiator will heat it up and consequently heat the liquid refrigerant contained therein, decreasing its ability to absorb heat in the evaporator. However, we're only talking increasing vent temperatures maybe 5 degrees, not rendering the system completely ineffective.