2005 Honda Accord EX. I thought I did everything right! I bought a vacuum pump on ebay. And a manifold gauge set. Pulled a vacuum. Waited. System held. Went to try to charge system and the refrigerant won't go in! The compressor doesn't start. So, I know this: 1) No leaks, vacuum held. 2) I was very studious in preparing for this "mission." I'm a handy car guy, but I've never done a/c before. I saw a really good youtube video by a guy called Eric the Car Guy, who shows every step. 3) I took GOOD notes from the video and followed it to the letter. 4) I cross-checked that video's info with other sources. I'm sure I did it right. WHY WON'T THE SYSTEM ACCEPT THE r134, and WHY WON'T THE COMPRESSOR START??

 

I had the same problem when recharging my AC on my Civic. Some said maybe the Schrader valve was clogged, idk. What I did was hooked the can up to the high pressure side and it was able to fill to maybe 40PSI? I figured at least there is some in the system then. I put the can back on the low side and manually jumped the compressor to come on being very careful to cycle it short not to run it dry. It took doing it this way but I still have no idea why it was so difficult.

 

Thanks Flewby. Good ideas. What you mentioned about the Schrader valve.... could mine be not working? After all, the low side gauge had a reading, and the gauge showed a vacuum....so you'd think the valve is open and functional. IDK. Thanks again.

 

With the valves on the gauges closed,crack/slightly open the connection where the yellow/center hose attaches to the gauges.You should get a hiss if the 134a source is correctly connected to the hose.I actually do this until I see/feel the coolant, in order to bleed the air out of the line.If you have coolant at this point,slowly/barely open the low side valve until you see 30-40 lbs on the gauge.At this point the line on the car where the low side port connects should be cold if freon is entering the system.If not,crack the low side line at the charging port and make sure you have coolant at this point.You possibly just pulled a vacuum on your gauges and never opened the schrader valve.Look inside the low/blue hose where it connects and make sure there is something to depress the valve and if not take it off the gauges and check the other end as usually one end does and the other doesn't, but the hose will connect from either end and seal(might want to check the high side also).When you get the system to accept a charge, the compressor will start cycling on its own,just give it time.DO NOT attempt to add freon to the high side!Very dangerous!

 

Wow, Bull. THANK YOU so much. Wow again. What a good and complete answer. The idea that I could've just pulled a vacuum on the hose itself - and nothing more(!) - is really smart. I would've never thought of that. Again.... thank you, thank you.... While it's been a little frustrating, I'm gonna have a blast on Saturday morning figuring this out! One more thing: there's not much to swapping out a Schrader valve, is there? Happy Memorial Day Weekend. David. .... oh, and thanks for the "high side" advice.... it sounded risky to me....

 

I don't think that there is a problem with the valve but possibly that the piece that depresses the center of the valve(like letting the air out of a tire) is either missing or on the other end of the hose.If you have the push on connectors it is possible that they aren't pushed all of the way down to the locked position.

 

Bull, Got it! Thanks.

David