A/C Problem
Thread Starter
Intermediate
Joined: Oct 2008
Posts: 40
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From: Red Oak TX
A/C Problem
My car an 93 i have a problem with the a/c it will stop blowing cold and i keep getting code 09. We check the freon it was not low i unhook the battery to clear code then a/c works for a day or two and then does the same thing. It's been converted to r-134 and has been working fine almost a year.
Last edited by nobull66; Oct 8, 2009 at 04:44 PM.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
System charge is monitored for how frequently the Low Pressure Switch opens/closes (pretty much anything over 8 times within a minute will set it) and/or whether or not the Pressure Sensor signal rises when the clutch is driven by the ECM. Most 9's are a low charge but an intermittent at the Low Pressure Switch might set it off. Take a look at the Connector making sure that it's on tight - wriggle it around while the clutch is engaged and see if that causes it to disengage. Otherwise, get the static pressure (a/c off) after the 9 has set along with the outside air temp. Use a DVM to see if the Low Pressure Contacts are closed. Monitor pressures with a manifold gage set. Scan it to see what the Pressure Sensor is sending to the ECM.
Thread Starter
Intermediate
Joined: Oct 2008
Posts: 40
Likes: 0
From: Red Oak TX
Allright i pulled a good vacuum replaced all the freon, car blowing cold i haven't got code 09 yet. I think the compressor not cycling right, at idle it cycles fine but if you rev it up to 1500 rpm or drive down the road you can hear and feel the compressor cycling no and off about every 5 or 6 sec does that sound right?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Somewhat depends on outside air temp, but it sounds like the Orifice is plugged up. Check pressures with throttle propped open so that it maintains a steady 1200 to 1500 rpms; cooling fan(s) running; system set to MAX. If it's 70 or better, it shouldn't cycle. If it does, note the cutout pressure (should be 25 psi for R12; 22.5 for R134). If doesn't cutout, force it to by pulling the Blower Motor harness. Then note the pressure when it cycles off. Post whatever you get and the outside air temp.
Thread Starter
Intermediate
Joined: Oct 2008
Posts: 40
Likes: 0
From: Red Oak TX
I replaced the Orifice tube what part is this my finger pointing at? this thing was loose i tighten it up a little made the compressor cycle better. Its made of plastic and feels like its striped and leaking does this have anything to do with the compressor cycling? 
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
That's the Low Pressure Switch. Too tight or too much torque will often make it worse as that destroys the o-ring sealing it. I'd replace it (hopefully the line fitting isn't stripped). It's on a Schrader so you don't need to discharge - just unscrew it as fast as you can. Lube the o-ring with compressor oil or just use 3-1 machine oil. Install until handtight then 1/2 turn. Check where it cuts out using the method I posted.
As to the orifice - was it full of metal or other crap? If so, it's better to flush everything forward - kinda depends on what put the crap there, but if the compressor seized, really important to get it all out. Otherwise, it'll plug back up.
As to the orifice - was it full of metal or other crap? If so, it's better to flush everything forward - kinda depends on what put the crap there, but if the compressor seized, really important to get it all out. Otherwise, it'll plug back up.
