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A/C only cools at idle

metalgod3082 on Sun April 07, 2013 7:29 PM User is offline

Year: 1994
Make: Acura
Model: Integra LS
Engine Size: 1.8L
Refrigerant Type: R134A
Ambient Temp: 85
Pressure Low: 35
Pressure High: 210
Country of Origin: United States

I'm trying to get my girlfriends A/C working for the summer here in Arizona. She drives a 94 Acura Integra LS 1.8L. So basically what is happening is it seems to cool alright if we are parked in the shade and the vehicle is idling. It gets to about between 50 and 60 degrees inside. Then once we start driving it goes up to about 80 degrees which is what the ambient temp is about right now.

I hooked up some gauges and low was about 15 to 20 psi and high was about 150 psi. I thought maybe it was just low on refrigerant so I decided it would be best to get the proper amount in to start troubleshooting this. I replaced the expansion valve, reciever/drier, and o-rings. Pulled a vacuum and it held for about an hour so decided to fill it up with two 12 ounce cans of r134a. I believe the integra calls for around 24 ounces.

So after putting the 2 cans in the low side was around 30-35 and the high side was around 200-220. Inside temp was around 52 degrees and felt nice and cold. This was while it was parked inside my garage. Took it for a spin and same thing happened. Inside temp jumped up to 80 degrees with a few minutes. When I rev the engine and watch the gauges the low side jumps up to about 50-60 psi and the high side stays around 200-220. I've sprayed off the condenser and also cleaned the evaporator the best I could when swapping out the TXV.

I'm now thinking it is something with the compressor but just wanted to get someone else's opinion.


GM Tech on Sun April 07, 2013 8:26 PM User is offline

so what are the pressures while driving- sounds like compressor is not even running....figure out a way to hold gages in the window so you can drive it..

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

metalgod3082 on Sun April 07, 2013 8:54 PM User is offline

The compressor is running. Why do you say the compressor is not even running? The compressor clutch engages right when the A/C is turned on and never disengages. I can see it spinning. When revving the engine around 2500 RPM the low side climbs to about 60 psi

Edited: Sun April 07, 2013 at 8:55 PM by metalgod3082

AutoCool on Mon April 08, 2013 3:35 AM User is offline

Does your heater control work correctly? At idle, does the temperature increase when you turn the temperature knob? Maybe you have a bad cable, heater valve or broken flap. Just a guess, you didn't mention if the motor was cold or hot before you went for a spin.

Do you see any signs of clutch slippage, does the clutch hub rubber look like it's melted? Clutch gap is hard to measure on your car but the hub is very easy to remove, just remove the center bolt and it will probably just pull right off. If it seems stuck then just find an M6 bolt ans screw that in, the hub is held on with an M5 but the hub is threaded M6 so the M6 will push the hub off.

I think GM meant your clutch may be slipping when you're out driving. Good luck.

metalgod3082 on Mon April 08, 2013 7:54 AM User is offline

Hmm that is a good theory. The heater control knob actually broke off as it was stuck and we tried to force it. I went under the hood and manually had to force the heater control valve with a lot of force. It moves back and force freely now but maybe something inside broke? Possibly not closed all the way and letting in the hot coolant?

metalgod3082 on Mon April 08, 2013 8:57 AM User is offline

Well it looks like the heater control valve is working properly when I manually turn it on and off. Started car today and it got down to around 55 degrees and when I turned it to heat I could right away feel heat coming out of the vents and when switching back to cold the air would immediately get cold again.

Also how can I tell if the clutch is slipping? Wouldn't I be able to just rev the engine and watch it or is it different while driving? As far as I can tell the clutch isn't slipping when it is just parked and engine revved.

Thanks again for the help!

Edited: Mon April 08, 2013 at 9:39 AM by metalgod3082

mk378 on Mon April 08, 2013 10:05 AM User is offline

Honda / Acura are infamous for reheating because the water valve doesn't get pulled fully closed with the dial on cold. You should be able to see / work on the mechanism on the bottom of the heater box under the center of the dash without any disassembly. Crawl in with your head near the gas pedal. If it's like a Civic (I think it is identical), there is a cable that comes down from the control panel and moves some levers which eventually move another cable that goes through the firewall to the valve. The push rod going off toward the right side of the car works the air door that bypasses most air around the heater core in the cold position, but it can't be counted on to completely stop the heat. The water valve has to close.

For summer use you can wire the valve lever closed under the hood, or clamp off the hoses.

Edited: Mon April 08, 2013 at 10:08 AM by mk378

metalgod3082 on Mon April 08, 2013 10:49 AM User is offline

Yeah i've made sure the valve is closed under the hood to prevent hot water from going into the heater core so I don't think it has anything to do with that at this point. The levers for this vehicle are actually accessed on the passenger side near the center console. Those are what I have been using as the knob on the control panel broke off. After further reading and research it sounds like it could be the control valve within the A/C compressor. I found a site that described the exact same symptoms I am having as it being the control valve. Do you know how I can find out what compressor a 94 integra has like if it is a variable displacement compressor or not?

Here is a link to the info I found

Edited: Mon April 08, 2013 at 12:19 PM by metalgod3082

AutoCool on Mon April 08, 2013 4:52 PM User is offline

The compressor in your Acura is a Denso 10PA15C, it doesn't have a control valve. It has 5 double sided pistons making it essentially a 10 cylinder compressor. There are reed valves for each piston, both suction and discharge. So no control valve, but if you have bent reeds then you could be blowing compressor discharge back to your suction side. They're just very thin spring steel plates.

The hub on your compressor uses a rubber ring as a dampener and "spring", you might not see any external signs of it slipping and it's hard to check the gap because you can't really fit a feeler gauge in between the hub and pulley face. The pulley face also has a ceramic ring built in so it's not just "metal to metal" contact between the hub and the pulley.

Here's what a 10PA17C (very similiar to yours) hub that was slipping looked like on the rear. Front looked almost new. It got hot enough to blue the metal. burnt the clutch coil to a crisp. I think you ought to remove the clutch hub and reshim the clutch, it's really easy.

Edited: Mon April 08, 2013 at 4:55 PM by AutoCool

metalgod3082 on Mon April 08, 2013 5:22 PM User is offline

Good info thanks! Do you happen to have any writeup for that procedure or links? And does that involve removing the compressor from the vehicle or can I leave it on and do this? Again thanks for the help

emsvitil on Mon April 08, 2013 5:25 PM User is offlineView users profile

Check the resistance across the clutch coil (should be about 4 ohms)

Also check the air gap on clutch (don't remember the measurement off the top of my head, but I bet someone here does...........)


AutoCool on Tue April 09, 2013 4:08 AM User is offline

There's a decent video on youtube that should make you more comfortable. You can probably disregard most of the video after about 1 minute of playtime. But watch the whole video because he reinstalls the hub.

Whether or not you can do this with the compressor installed depends on access, you just have to look yourself. If you have more than 4 inches in front of the compressor hub then it should be easy to check the hub and adjust the clutch gap with the compressor on the car. You might have to remove your fender liner or something. There is a clutch holder tool that you may need to prevent the hub from spinning while you loosen the hub bolt. But once you remove the bolt the hub should slide right off. If it seems stuck, just push it off by threading an bolt into the hub. The hub is held on with an (M5?) bolt and the hub is internally threaded to accept an (M6?) bolt.

Be careful not to lose the shim or shims while removing the hub, they just might fall out and disappear. Like I said, I don't think it's easy to check clutch gap on that compressor model because the pulley face is concave or whatever.

While the hub is removed, use an inspection mirror and look for any signs of a leaking or overheated clutch bearing, maybe even loosen the drive belt and spin the pulley by hand. also a good idea to check the resistance of the coil with a multimeter.

Search youtube for "Denso 10PA clutch bearing replacement"

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