Honda S2000 A/C not cooling - warm air

[TopDown]

My vehicle sits and gets used maybe once a month. Today upon using it I noticed the a/c was blowing warm air. I got the gauges out and: Car off; both LOW and High were equal at 85/85.....Started the car; Low side 78psi - High side 105psi. Let the car warm up and still no change. What I did notice was the Low side upon acceleration the psi's went down and the more I revved it, the more the psi's went down basically to zero. Meanwhile the High side never moved and stayed at 105psi.

All this is happening while ac clutch is engaged and no noise from the compressor. The clutch does not recycle off when the Low side drops at acceleration.

I then thought maybe it was low on r134a so I properly had it evacuated, 30 minutes vac, hold vac 45 minutes and recharged to spec 19.4 to 21.02 oz of r134a using a tad of UV dye.

So, its basically doing the same thing. Low side up and won't come down to 30-40psi and the High side is low and won't go up. My car has approx 105K miles and it has a factory Keihin HC-090R compressor.

Any help would be appreciated before I start replacing parts I don't need to like the Compressor, Expansion valve or dryer.

[Cornbinder89]

Car's aren't my area, there are so many variation. Your pressures point to a compressor not compressing, but I don't know if this has a variable compressor or not. slipping clutch or belt would give the same result.

[Tom Greenleaf]

Your equalized pressures just strongly suggests a large to total leak stops at just "some" refrigerant? Can't know but coincidentally those pressures just playing look like what refrigerant would be just still at temp you may be working around. Charts for that you'd see. Also just air if a compressor engages would make the silly 105.

Do use the UV dye, some you can just see it, run finger under lines and connections. Look for oily mess at compressor it may be dry it wasn't running and wouldn't leak there again now maybe hear it or need a sniffer right there. Pricey things and hard to bubble test this probably leaks enough for that like leaks in tires! Good luck have to start somewhere to know anything more about the system now at a whole when it can hold a proper charge into a well held vacuum,

[TopDown]

The system is properly charged and there is no leaks verified by vacuum holding after 45 minutes and no residue on lines. Static pressure is good, even across when engine is off. What I see is that the lines are not getting cold which is leaning me towards compressor issues. Also the high and low pressures are the same when at idle which again feels like the compressor not holding pressure.

[nickyanc]

The system is properly charged and there is no leaks verified by vacuum holding after 45 minutes and no residue on lines. Static pressure is good, even across when engine is off. What I see is that the lines are not getting cold which is leaning me towards compressor issues. Also the high and low pressures are the same when at idle which again feels like the compressor not holding pressure.

Do not get fooled by thinking that there are no leaks in the system just because it hold vacuum for 45 minutes, green dye is good it will show some leaks but the best way is to check for leaks with a good leak detector,anyway the problem you have could be only 2 causes: your compressor it's not pumping very common on this type of scroll compressor but could also be your Tx valve stuck open and the only way you could have eliminated this problem was the way you regased your AC system. The proper way to regas is through the red side (liquid) and make sure the blue tap is closed. Open the red tap slowly and let liquid refrigerant in the system and watch the blue low side gauge and see if the needle is moving up slower than the red gauge needle (liquid got to pass through the Tx valve to reach the low side) if the blue gauge is moving up as fast as the red one than I would say that your Tx valve is stuck open, a very rare case but it's cheaper than the compressor. Hope this help

[Cornbinder89]

Tx valves are never "open nor "closed" they always have some restriction but always pass some refrigerant. The size of the restriction varies. If you are getting no pressure rise across the compressor at idle, it point to the compressor.

[TopDown]

Update: So today I completed my ac work for the issue explained. I was very lucky to have been offered a used Keihin compressor from a local s2000 owner. I changed out the expansion valve which had so much crude in it, changed out the dryer, all o rings and flushed out the system. Added 4 1/3 oz of Pag 46 and vacuumed and recharged the system. The A/C is now blowing ice cold air with both the low and high side within specs.....Looks like it was the compressor causing the issues.

[TopDown]

[Cornbinder89]

A lot of what looks like aluminum. If it is working good, then you might have got all the junk out of the condensers, but if it struggle then I would suspect the condenser. It is always hard to get all the debris out of a system. Thanks for the update, many time we never hear back and always wonder what happened.

[Cusser]

Hoping it stays that way !