Originally Posted by 2001NBMZ28
The pressures are going to be different depending on ambient temp and humidity. Try searching the site and see if there's an A/C Perfornance Chart for your year or maybe someone can post one. Here's what my Helms says for one set:
86-95*F - Below30% humidity 40-44 psi low/213-251 high, 66*vent.
Above 30% humidity 42-46 low/218-261 high, 68* vent.
Edit: Your P0420 is for a bad drivers side cat - you might still be under the GM 10 year/120K extended warranty for it.
Thank you both!
1st - Wow! Thanks for the tip on the cat!! I'd priced them before (yikes!) and decided it could just keep throwing that code.
I called this morning to find out. The first place I called wanted my vin number and sort of hemmed and hawed around. The second dealership I called just got back to me - asked my mileage and said yes, I was covered since I'm only up to 111k. So I've got an appointment a week from today for them to scan the code on their end and then order the part. Yippee!! Thanks so much!
Now back to the AC issue. I flipped the house over last nite looking for a thermometer for an accurate reading. Saw that Harbor Freight has their $60 Infrared Thermometer on sale (Today only and must print coupon?) for $25.99.
So I now own one and can say with some certainty that my car isn't cooling at all. The temp reading varied right around 90-93 degrees. Same temp as outside. I'm down near Tampa, FL and the temp outside is sitting at 90. Humidity is 43% according to the local weather channel.
I guess I just thought it was cooler because the car interior is about 20 degrees hotter sitting out in the sun. (registered 111-113 shooting the ceiling or down at the gas pedal - items in "shade") Doh.
That Helms chart - is that referencing a 2001 Z28? (based on your user name) It looks like the GM service manuals cover Firebird and Camero in the same book. Tho dunno if the ratings are the same though my guess would be yes.
My initial reading was about 70 low side / 200 high side. (pre-freon add) Should I still try and bleed off some of the freon that we added to push the high side up to 250?
Do you guys think that the compressor could be bad even though it's running? The diagnostic chart that I found suggested if the LP side registered High, and the HP side registered low - that the compressor or the control valve has failed. I've got the exploded diagram of the system but still studying it to try and figure out which "control valve" they're talking about... And I assume I'd have to open the system to change it once it's identified? Anyone know which valve they're talking about and how to test for failure? (apart from hotternell AC air?)
I believe there's an AC parts wholesaler up in Jax with some good deals - and my dad is up there for a couple days. Hoping I can figure out what I need and ask him to pick it up for me before he comes back. (unless I look at the ebay route for a deal)
Ugh - That learning curve seems extra steep when it's tied to your AC - LOL! Thanks again for all the help!!