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lsturm
Novice
Aug 16, 2013, 9:14 AM
Post #1 of 22
(4679 views)
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Sunfire A?C Problems
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I have been working on the AC on my grandson's 2000 Pontiac Sunfire with the 2.2 engine. Flushed all lines and the evaporator until everything was absolutely clear. Had some old oil and a few particles in the evaporator but it cleaned up good. Replaced the compressor, accumulator and condenser as well as the orifice tube. Also replaced the pressure switch ( on this car it has the high and low pressure switch.) Practically a new system except the hoses and evaporator. Now here is the problem. The ac will start and cool for a few minutes and then the clutch will kick out. Using manifold gauges, at rest pressure is balanced at about 90 lbs. When running the low side is about 60 and the high is about 155. Those look pretty good to me. I thought that it might be building pressure if it happened to still have something in the evaporator that I didn't get out, but after checking with the gauges as it runs, it is not building pressure. It just stops pumping and the pressure stabilizes on both sides. I will still have to double check to make sure the new pressure switch is not messing up, but I am stumped. Anyone out there who has any ideas on what I can check next I would really appreciate a response. Forgot to say I pulled a vacuum for about 2 hours and let it set overnight with no vacuum loss, then ran the vacuum pump (two stage Welch) another two hours before charging. Thanks for the help.
(This post was edited by lsturm on Aug 16, 2013, 9:32 AM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 9:30 AM
Post #2 of 22
(4662 views)
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Re: Sunfire A?C Problems
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What happened to the old compressor?
Is your replacement compressor a reman, salvage yard, or new?
How much refrigerant did you put into the system?
It shouldn't be kicking off with those kind of pressures.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Aug 16, 2013, 9:41 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 9:40 AM
Post #3 of 22
(4655 views)
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Re: Sunfire A?C Problems
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This is worth the read for system charging........
http://autoforums.carjunky.com/..._A/C_SYSTEMS_P45460/
This car should (charts can be wrong) hold just 24 oz, 134a, 9 oz of PAG 150 exactly and the gas into a well held vacuum, 29.92Hg at sea level.
* Did you have a good vacuum?
* Did you spin oil thru new compressor a dozen or more times?
* Reman or new? Remans have high failure rates IMO.
For now I think charge is all wrong, O tube may be wrong or broken in some way, compressor already burned out if close and I mean real close on proper charge with those #s.
If you didn't measure in charge by weight you could have passed the right amount and bad things happen up to choking a compressor.
You said it was cool/cold for a short while so either it worked for a moment or was just during charging which doesn't count until stable and running for a good bit, all components in good working order,
T
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lsturm
Novice
Aug 16, 2013, 9:55 AM
Post #4 of 22
(4647 views)
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Re: Sunfire A?C Problems
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Thanks for the quick response. I used spec charges. Two full cans (12oz each) or 134a and 9 oz of Paq 150 measured on my wife's kitchen scale to make sure I got the right amount. Poured 5 oz in compressor as the installation instructions to new (not a remanufactured) compressor said and rotated it with a wrench at least ten times before installing it. The other 4 ounces went into the accumulator. The old compressor had a seal out and the boy had used leak seal and gunked stuff up which is why I changed everything but the evaporator which is too much of a job for that old car when the evaporator wasn't leaking. I think I got that part right. I did note that the new orifice slipped in the condenser a lot easier than the old one came out the old condenser, but wouldn't I see a change in the pressure on the manifold if the orifice was leaking and even if it leaked as long as the high and low pressures were in tolerance would not the compressor keep pumping? Thanks again for the help and ideas. Again I forgot to say that while it runs it brings temp on thermometer in center vent down to about 48 degrees.
(This post was edited by lsturm on Aug 16, 2013, 10:03 AM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 10:39 AM
Post #5 of 22
(4639 views)
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Re: Sunfire A?C Problems
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You have the correct charge. How long did you have it on vacuum? Is this a reman, salvage, or new compressor?
The compressor on that is a variable displacement compressor. It shouldn't be turning off. The switch is actually a pressure sensor that sends between .1 - 4.5 volts to the engine computer. .1 volt would equate to 0 psi and 4.5 volt to 450 psi. You should monitor the voltage at the sensor and see what it is reading when the compressor kicks off. The signal wire is red/black.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 11:11 AM
Post #6 of 22
(4635 views)
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Re: Sunfire A?C Problems
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Where did you put the oil?
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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lsturm
Novice
Aug 16, 2013, 11:28 AM
Post #7 of 22
(4631 views)
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Re: Sunfire A?C Problems
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It is a new compressor, and I did all the flushing and parts replacing to maintain the warranty. I pulled a vacuum to 1 bar for a couple of hours and let it set overnight, then let the vacuum pump run for another 2-3 hours before charging. Can you think of any other reason a variable compressor clutch would disengage if the pressures were between the high and low cutoff limits? Since the compressor runs after sitting awhile, but then cuts off after a few minutes, I thought a blockage on the high pressure side was the problem, but I don't see it on the gauges. Pressures start out uniform on both sides and then seem to be ok on the low side but only about 155 on high side. I couldn't tell if that was lower than it should be, but it is definitely within the pressure switch range on both ends and when it runs it cools good. I could have a sensor problem even though the sensor is new. I will check the voltage sent back to the computer during operation and at the time it cuts out as you suggest. I thank you for the help and will post back with my results after checking the sensor.
(This post was edited by lsturm on Aug 16, 2013, 11:44 AM)
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lsturm
Novice
Aug 16, 2013, 11:38 AM
Post #8 of 22
(4630 views)
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Re: Sunfire A?C Problems
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This was a new compressor was shipped with an ICE charge and the instructions said not to remove that charge. It had a sticker saying to add oil through the drain port and to turn the compressor 10-12 times. I may have turned it a few more times than that since I spun it slowly with a socket and normally give whatever I am lubricating a few extra turns for good measure.
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 12:13 PM
Post #9 of 22
(4622 views)
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Re: Sunfire A?C Problems
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Just making sure you did use the plug.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Discretesignals
Ultimate Carjunky
/ Moderator
Aug 16, 2013, 12:33 PM
Post #10 of 22
(4617 views)
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Re: Sunfire A?C Problems
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Sounds like you got the mechanical part of the system under control. There was a TSB on the wiring harness for the pressure sensor being too tight. The torque from the engine would stretch the wires causing intermittent ac operation and a P0530 code to be stored in the PCM.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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lsturm
Novice
Aug 16, 2013, 12:47 PM
Post #11 of 22
(4613 views)
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Re: Sunfire A?C Problems
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Discretesignals, Thanks for telling me that. If I can't tell what is going on when I check the sensor, I may have to take it to a shop or get a GM code reader. The mechanical parts can be figured out, but the newer computer controls drive me crazy. My dad was a mechanic and I worked in his shop part time 50 years ago, but things are a lot different now.
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lsturm
Novice
Aug 22, 2013, 9:14 AM
Post #12 of 22
(4571 views)
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Re: Sunfire A?C Problems
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This is an update to posting to let everyone know the current status. First I pulled the plug out of the sensor and checked all three wires for continuity to make sure there was no break or short. Then I hooked up the gauges again and also put a pin in the red/black sensor wire. Attached a voltmeter to the sensor wire and started the car. The a/c worked great. The low side was 45-50 lbs and the high side was about 225 lbs at a high idle. The voltmeter read 2.26 volts. When it idled back the suction line was about 55 and the high was at 195 with a corresponding decrease in the voltage to about 1.98. All seemed to work good and the ac did not cut out like it had been. I thought that perhaps the sensor plug had simply not been in good enough. I then drove it into town to get breakfast. Cooled down to 40 degrees at the center vent as shown on ac thermometer. Did a great job and ran about 15 minutes to get to breakfast.
Then the hammer fell. When I started the car to go home the ac started and ran for about 2 minutes and cut off exactly as it had before. I rechecked all fuses and made sure I had power at the relay with the key on. I switched out the relay with the fuel relay which is the same as the AC and no difference. (Jumping the relay starts the clutch, and the a/c maintains the same pressures as mentioned before so I am fairly sure it is an electrical problem) At this point I am thinking it may be the PCM, but I am not sure it would work at all if it was the PCM. Before replacing the PCM I am going to check to see if I get a ground at the relay with the key and a/c switch on. What I think I have learned is that the PCM causes a slight throttle increase and starts the cooling fan as well as providing a ground to the relay when the A/C is turned on. This thing is killing me and I hate to admit defeat or, worse, that I can't fix anything I work on, but in this case a surrender and a trip to a real mechanic may be the best thing for my sanity. I you have any more ideas let me know thanks.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 10:21 AM
Post #13 of 22
(4569 views)
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Re: Sunfire A?C Problems
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Agree, you probably could use some help to polish this off.
Just one thing is I don't understand that you saw 40F at center vent with low pressure reading at high idle so high? That alone isn't the problem IMO just doesn't add up for a single system.
See this chart - pressure of refrigerant is near exactly pinned to the temp of it.......
That would be the temp at the port close to that at evap and add several degrees just passing thru ductwork,
T
(This post was edited by Tom Greenleaf on Aug 22, 2013, 10:23 AM)
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lsturm
Novice
Aug 22, 2013, 10:57 AM
Post #14 of 22
(4560 views)
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Re: Sunfire A?C Problems
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I don't know what the difference might be. I noted at fast idle ( est. about 1100 RPM) the low side was about 45-50, while at low idle (about 850RPM normal idle) it was about 55. I didn't explain it well. At normal idle I was only getting about 57 or 58 degrees at the vent. When I went to breakfast on the road I got 40 degrees but the engine was turning closer to 2000 RPMs. I don't know if that is supposed to make a difference, but the air in that car works better moving than when sitting at a light, always has. I didn't test it with gauges at 2000 RPM. Thanks for the response and the chart. I will keep it for future reference.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 12:29 PM
Post #15 of 22
(4556 views)
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Re: Sunfire A?C Problems
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? There may be issues with accuracy going on as the chart shown is exact - tested. With an infrared thermo I can tell the pressure in a tank vs low of the car without touching gauges!
This is actually more fancy than about 10 I own less than $10 bucks and fast/accurate. Wired household thermos. Generally like this.......
OK - you can run the wire deep into the center vent, place the base unit in front of condenser which is the temp the car is dealing with and switch indoor/outdoor and get both temps while checking things underhood.
They have these for cars at parts stores, Wallyworld, home centers and plenty of places.
Just because I'm crazy I have two in each of my own cars that stay there reading actual incoming air temp and center vent temp all the time. It's interesting to me anyway and noted that when I ask for vent which should just be the same as incoming air temp is up by chart a few degrees as said just from the ducts and engine heat not totally insulated from firewall too.
The dial type seem slow, harder to read for me and you can be rubber necking in and out checking it while fussing underhood so set that one on the dash and set what the heck is really going on at what RPM.
That just handy fast and informative as so much is temp related along with what pressure. Actual air temp and performance is key, totally related, not the weather temp forecast.
THIS STILL SHOULD JUST SHUT DOWN - That is some other crap not behaving - switch, sensor a connection giving the computer now bad info probably. That's why with all you've done there's a missing something and may take some help with more high tech equipment no doubt not worth owning if you want to do just this car.
You seem to have done things right and the gremlin is hiding so far??
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 1:02 PM
Post #16 of 22
(4551 views)
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Re: Sunfire A?C Problems
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Driving down the road starts recooling inside air, increasing compressor RPM and increasing air flow across the condenser, all of which will lower the pressure and temp driving down the road so what you saw with your gauges parked is not what you are getting going down the road.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 2:57 PM
Post #17 of 22
(4548 views)
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Re: Sunfire A?C Problems
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Hammer - do these use two speed fans? What's with it cutting out - perhaps unseen unless you left gauges on it under wipers to watch pressure while driving and that's been done a spike in pressure and HPCO kicks it off?
Not adding up to me??
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 3:10 PM
Post #18 of 22
(4544 views)
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Re: Sunfire A?C Problems
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It's a single speed fan that turns on with the compressor but shuts off at 38MPH. I don't remember what his issue with the fan was here.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 22, 2013, 3:21 PM
Post #19 of 22
(4541 views)
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Re: Sunfire A?C Problems
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Reported high pressure doesn't reflect serious lack of air flow to me at RPMs.
IDK - funky electrical or perhaps some reason that escapes notice. I've heard of radiant heat back to condenser from radiator but that' real rare and should reset I would think.
Pressures don't suggest it's 120F outside either if all is close with charge.
Just a couple odd things have been under bumper spoiler/air dam messed up air flow and a Honda once has the front license tag blocking most ( well a lot anyway) of the air flow of the grille!
Bit of a hair puller right now - need more info and checking I guess,
T
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lsturm
Novice
Sep 20, 2013, 9:49 AM
Post #21 of 22
(4468 views)
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Re: Sunfire A?C Problems
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I wanted to finalize this posting by reporting on the final outcome and thanking the experts for all the help.
After going through everything in the posts above, I checked to make sure I was getting the ground to the compressor. I bought a code tester to see if I could determine if the computer was sending the proper signal to ground the compressor clutch. The computer checked out ok, but I had pulled off the fender panel to get to the computer and had also recheck the wiring all the way around. I loosened and then re-tightened the wiring harness on the computer to insure connection.
Somewhere in there the connection was made. Where the clutch used to kick off after 5 or 10 minutes, it now runs perfectly and the AC works as it should. I have now run it fro about 3 weeks with no problems. I wish I could have isolated where the wiring issue emanated, but I am happy to say that it now works.
I don't work on AC often, but this was the toughest I have worked on (but then it is a Sunfire) and the suggestions put me on the right track. I also copied off the chart and will keep it for reference when someone wants some help.
Again thanks for the many suggestions.
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 20, 2013, 11:46 AM
Post #22 of 22
(4462 views)
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Re: Sunfire A?C Problems
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Glad to hear you fixed it. Thanks for following up with up
I'm closing the question now as solved to keep the spammers out.
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