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[Joseph Davis]

OK, I used to be decent at this shit, but it's been 12-14 years.  Help me logic this out.

Background: A friend buys an EG sedan with an LS swap, buys all the (used) pieces to put AC on it, evacs the system and charges it.  It's never worked right. 21-23 ounce system, he probably put 24 or a little less in.  Not sure if any oil was introduced to the system.

- 85 degrees ambient, at idle low side pressures never go below 55, high side slowly climb to 375 where the safety switch cuts the compressor off, takes maybe 30 seconds to do this.  If the engine is revved, high side pressures come all the way up to cut off in ~2 seconds.

- The vent does blow cool/cold when the compressor is operating. 

- Compressor discharge line to condenser is hot, condenser exit line into filter drier is hot, filter drier line to THX is hot.  Evaporator is obviously cool/cold, and suction line going from evaporator to compressor is cool at best.

- Turn the engine off and 10-15 minutes later they system pressure still hasn't equalized.  ~30 psi difference.  It's been a decade, but I think it's supposed to be equalized a lot quicker?

- Condenser fan is an aftermarket push type which doesn't push a lot and I think is inadequate, but should be fine - at least for longer than 30 seconds. 


I'm leaning towards a stuck partially open THX with a side of put an OEM condenser fan on the damn car.

[Joseph Davis]

I can drizzle water across the condenser and pressures stay at 50-55/290-300 at idle. 

[Robb]

Fan and questionable drier.

[Joseph Davis]

OK, help me push the logic buttons.

- Fan since it isn't dropping temp across the condenser, got it.

- Questionable filter-drier, sure, but how will that affect the system ie moisture being in the refridgerant?  I thought it justs killed system efficiency.

- Lack of oil (I doubt any was added when the AC was installed) only manifests in compressor life, right?

[HiProfile]

I always thought if you added 10% more fluid to a closed system, in addition to the moisture the drier absorbed over a few years, and you end up with excessive pressure? Or maybe the idea behind a hydrolock doesn't work with A/C systems.

[snm95ls]

I can drizzle water across the condenser and pressures stay at 50-55/290-300 at idle. 

Shitcan the condenser fan that is on the car now.

Idle low side  pressures depending on the ambient conditions are probably right on target.  If you can't get the low side pressure to the 33-40 psi area with the engine RPM around 2000, then you have other issues.

How are you gauging how much refrigerant is being introduced to the system?  If not using a scale, then you are shooting in the dark. 

It honestly sounds to me like it might be slightly overcharged as well, but the condenser fan issue needs to be addressed first.

Also, what are the outlet temperatures like when you keep the high side pressures under control?  Is the recirc door working properly?

[CSaddict]

Over charge, air in the system or condensor can't move the air through it.

[Joseph Davis]

Idle low side  pressures depending on the ambient conditions are probably right on target.  If you can't get the low side pressure to the 33-40 psi area with the engine RPM around 2000, then you have other issues.

When I was pouring water on the sumbitch I could hold the throttle to 1500-2500 and get low side to go 30-35 and hold steady.

How are you gauging how much refrigerant is being introduced to the system?  If not using a scale, then you are shooting in the dark. 

I haven't.  The guy who charged it said "two cans" so 24 ounces.

Also, what are the outlet temperatures like when you keep the high side pressures under control?  Is the recirc door working properly?

Outlet temps feel great on my hand.  Is that specific enough?

[snm95ls]

Fix the condenser fan.

With such precise information, I wonder if the system was pulled to a vacuum when it was "evacuated" or whether the Schrader valve was pulled to do an R134 retrofit.  There is a 50/50 chance for a 92-95 Civic that it  was originally R12 after all.

[colt45]

^ agreed. also, the dryers can get fucked up if left to sit on a shelf and not sealed.

[DmC]

http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

[crttaz]

92-93 = R12

94-95 = R134a

[j.h.christ]

a/c is for rich people

[snm95ls]

a/c is for rich people

I'm rich bitch!!

That venturi vacuum dealio works really well.  I use one when I do AC work at the house.

Bone, yeah kind of a gimme since R134a was mandated for 1994 and later.