A/C Weirdness..anyone else having this
 

So when i first get in the car..first start of the day..when car is cooler..I switch on the a/c and it cools down great..about 40 deg. blowing out of the vents...

my problem is, is that when I stop somewhere and shut it off and come back and turn it on again it won't cool down like it did..only blowing out of vent approx..55 deg.

I'm wondering if there is some sensor that needs checked..I know of the interior sensor behind the glove box and the anti freeze switch on the left side of the heating and cooling control unit near the infamous "clips"

So I am dreading the thought of replacing the expansion valve...

anyone have this problem and what did it turn out to be.....please be a $5 switch..LOL

You didn't really give enough info to truly diagnose. Here are a couple thoughts though...

Are you using recirculation or fresh air?

Generally, the AC can only cool the air down so much vs. the outside temp. Mine cools great when it's 88 degrees out but not as well when it's 98 degrees.

It's easier to keep a cool car cool than it is to cool down a hot one.

I believe the heater valve is the same as the 928. Being that when off and vacuum is gone it defaults to open (or if vacuum leaks then will not close ) So when car is run and turned off there is hot fluid introduced to blower assembly and must be cooled off also.

I recently had to replace some seals on the compressor on my '84. When I recharged (I have all equipment and freon ) I was (am getting 28 degree off the center vent with probe before cycling of compressor (It is very very cold and I am happy)

As cj writes it is easier to keep a cool car cool and with your location the high heat will always be a fight. Recent 100+ temps here showed mine still working very well, but after shut down and restart it took some time to pull center vent temp back down. I have observed that 'in town ' driving will result in a bit higher temp while the better air flow of highway driving will provide much cooler air sooner. This is due to undersized fans on the car (my opinion only). For this my solution was to weatherstrip the sides and top of the radiator/condenser so when the fans kick on they pull more air through the rad and condenser.

Hope this helps some.

Make sure your fans are working properly. It would be a good idea to remove the radiator and and clean the condenser too. Debris in the fins causes higher high side pressures and higher freon temperatures which lead to higher temperatures at the vents.

It could be your heater control valve (HCV) isn't closing properly once the car is warmed up. On a acold start, it should get a signal to close, regardless of what other control settings are, in order to get the engine up to temp as quickly as possible. Once the engine is warm, it takes into account what your HVAC controls are set at. If you have the AC switched on and the temperature turned full cold, this _should_ signal the HCV to close, but if something is not working properly, it may not be getting the memo.

To test the HCV-not-closing theory, you can force it stay closed by tying a zip-tie around it. If the behaviour changes, you at least know where to look next.

Has the car been switched over to R134a? I had a hell of a time getting the charge correct on mine when I went from R12 to R134a. Took two separate attempts and the A/C guys never got it right (to be fair, they were charging the system on cool days, in the 60's, and it would seem fine until the temps got into the upper 80's).

I ended up recovering the R134a myself and charging with an EPA-approved alternative. Works perfectly now. I'm not a fan of R134a in the 944/951/924S systems as they aren't the strongest in the world to begin with. The lower efficiency of R134a does not play well with a system that was not the greatest R12 system to begin with.

If you really need R134a, I strongly recommend fitting a larger condenser in addition to the new receiver/drier. A more powerful compressor wouldn't be a terrible idea either.

Aaron, dont leave us hangin with the EPA-approved alternative tell us, tell us!!