A/C compressor issue or something else?
#1
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Car: 1987 camaro
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A/C compressor issue or something else?
ok, so ive done some searching around and cant seem to find an answer, for sure. i have an 87 z28 with a 305, an edelbrock carb(5 speed car also) i do have a serpentine setup on it, which came off a v6 s10 iirc so it uses a truck belt.
the problem im having is the compressor vibrates between about 1000-1500 or so rpm and when the rpm drops back to idle with the a/c on, sounds like im grinding the gears. everthing is fine when the a/c is off. i have replaced the condensor, accumulator, and the compressor with a reman one. the old one was makeing the vibration noise as well. everthing is tight as far as i can tell
not sure where to look or what i should do, any help would be awsome...thank you in advance!
the problem im having is the compressor vibrates between about 1000-1500 or so rpm and when the rpm drops back to idle with the a/c on, sounds like im grinding the gears. everthing is fine when the a/c is off. i have replaced the condensor, accumulator, and the compressor with a reman one. the old one was makeing the vibration noise as well. everthing is tight as far as i can tell
not sure where to look or what i should do, any help would be awsome...thank you in advance!
#2
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Car: 88GTA
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Re: A/C compressor issue or something else?
Here is the brace on my 88 GTA
See this Thread
https://www.thirdgen.org/forums/tech...on-alt-ac.html
See this Thread
https://www.thirdgen.org/forums/tech...on-alt-ac.html
#3
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Car: 92 Camaro RS
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Re: A/C compressor issue or something else?
There is a similar type of brace that goes from the back of the compressor
to an exhaust manifold bolt. If you don't have one I think I have a couple
around somewhere. At least that's how the stock 5.0 serpentine systems work. Don't know if yours
is the same
to an exhaust manifold bolt. If you don't have one I think I have a couple
around somewhere. At least that's how the stock 5.0 serpentine systems work. Don't know if yours
is the same
#4
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Car: 1987 camaro
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Re: A/C compressor issue or something else?
i may have the brace around somewhere....should be close to stock 5.0's, ill be looking around to see if i do have them tomarow...however it has gotten better, found that the compressor mount was loose as was the idler wheel, tightened them up. still seems to do it though just not as loud.
i have also noticed that if you rev the engine up a little the tensioner moves which obviously puts less tension on the belt, is this normal? or sign that i need a new one?
belt does vibrate like a guitar string a little bit next to the crank pulley as well
thank you
i have also noticed that if you rev the engine up a little the tensioner moves which obviously puts less tension on the belt, is this normal? or sign that i need a new one?
belt does vibrate like a guitar string a little bit next to the crank pulley as well
thank you
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Re: A/C compressor issue or something else?
Vibration not good. Sounds like some kind of misalignment of pulleys or something.. Mismatched parts? IDK
#6
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Re: A/C compressor issue or something else?
ok vibration is fixed, just needed a brace. i found one around the house put it on and its all good now.
only issue now is that compressor cycles constantly. read that i should have about 27 psi on the low side and 225 at the high side when its 80 degrees...its been 90 plus lately so i put more in...hangs out around 50 psi on the low side and seems to cycle when it hits 252 on the high side.
i bypassed to high pressure switch to see what would happen and sure enough compressor stayed on...this also made the low side pressure go down to 40ish psi and high side get to 300ish, will have to check that again for more accurate numbers. my question is: is the high pressure swich starting to go or do i have too much in the system?
fyi i have replaced the compressor, condensor, the accumulator and the high pressure tube if that affects anything
thanks again for all the help!
only issue now is that compressor cycles constantly. read that i should have about 27 psi on the low side and 225 at the high side when its 80 degrees...its been 90 plus lately so i put more in...hangs out around 50 psi on the low side and seems to cycle when it hits 252 on the high side.
i bypassed to high pressure switch to see what would happen and sure enough compressor stayed on...this also made the low side pressure go down to 40ish psi and high side get to 300ish, will have to check that again for more accurate numbers. my question is: is the high pressure swich starting to go or do i have too much in the system?
fyi i have replaced the compressor, condensor, the accumulator and the high pressure tube if that affects anything
thanks again for all the help!
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Re: A/C compressor issue or something else?
You are low on charge.
How are you filling it? 30# Cylinder or AC Charge bs from AutoZone?
How are you filling it? 30# Cylinder or AC Charge bs from AutoZone?
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Re: A/C compressor issue or something else?
have been getting cans from autozone, i dont have access to the larger cylinder
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Re: A/C compressor issue or something else?
i did, pulled down to almost -30
so if put more freon in will that allow the high pressure side to go up higher?
or is the switch going, seems to activate at 252 psi
so if put more freon in will that allow the high pressure side to go up higher?
or is the switch going, seems to activate at 252 psi
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Re: A/C compressor issue or something else?
Where did you by pass the switch...the LOW is on the Accumulator. If its low, your compressor is going to cycle. Sitting in the garage while charging, it probably wont cycle due to no air across the condenser. Feed it slow and watch the low side. The high will go up until it cycles, then come back down. Never Never bypass HIGH side Pressure Switch on compressor....that's trouble!
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Re: A/C compressor issue or something else?
yea i know, never left idle speed was just messing with stuff just to check it.
i jumped the connector on the low side too to check it compressor still cycled, low side pressure sits at 50 psi though
i jumped the connector on the low side too to check it compressor still cycled, low side pressure sits at 50 psi though
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Re: A/C compressor issue or something else?
If you pressures are sitting at those numbers, take it out on a sustained cruise and put a temp probe in center vent. You are in the ballpark of 40-45* air.
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Re: A/C compressor issue or something else?
ill be taking it out today so i can check that...i did put a probe in the vent the other day as well and it only got down to 70 or so
#16
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Re: A/C compressor issue or something else?
Ok so crusing vent temps get down to 60-62 and the compressor is cycling constantly...its about 95 degrees with hunidity right now, system has about 50 psi low side
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Re: A/C compressor issue or something else?
Is it still kicking out at around 250 PSI? If so, I would replace the high pressure switch.
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Re: A/C compressor issue or something else?
I was kinda thinking that was the issue, how high can the high side get without damaging anything?
#20
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Car: 91 Firebird, 89 Bird, 86 Bird
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Transmission: None, T5, Thm 350
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Re: A/C compressor issue or something else?
When you pulled a vacuum on the system did it hold the vacuum for an extended period of time? Such as 15 mins or so? Not really important to the pressure and cycling unless you are leaking refrigerant.
Do you have any idea how much r134a you have put in the system? Your car calls for 3 pounds/48oz of r12 and when you retrofit r134 into a r12 system you only need 80% as much refrigerant, if I am remembering right "Edit i referred back to the ASE training text, Auto Heating and Air Conditioning third edition by Chris Johanson, and 70-80% is best* So that is 36.4 oz or a hair over 3 of the little 12oz cans. Overcharging the system can reduce how cool the air is just as much as undercharging.
Of course it should only cycle whenever the low side pressure is lower than the switch is set for and the high pressure is higher than what the switch is set to trip at.
Snap ons service manual program says your low side switch should cycle on at 46 psi and shut off at 25 psi. If low side pressure is never getting below 25 and the compressor still cycles with the switch bypassed than it is probably a bad high pressure switch. As was previously mentioned you should never bypass a high pressure switch for any type of diagnosis except maybe for a system that will never engage the compressor. With that said scrap on says the high pressure switch is only supposed to cut off the compressor if high side pressure exceeds 410 psi and then resume operation when pressure drops back to around 150-250 psi. That high pressure cutoff seems pretty high to me so the data might not be 100% accurate.
I don't know if 87 does but my wife's 86 has a switch in the power steering line right above the steering box that is supposed to cut off the compressor when the power steering pump is under a heavy load in order to prevent stalling. Like when parking. Might check that switch out.
Hopefully this helps, if it doesnt help you then maybe it will someone else. It felt like it took hours to type this up on my tablet. Lol
Do you have any idea how much r134a you have put in the system? Your car calls for 3 pounds/48oz of r12 and when you retrofit r134 into a r12 system you only need 80% as much refrigerant, if I am remembering right "Edit i referred back to the ASE training text, Auto Heating and Air Conditioning third edition by Chris Johanson, and 70-80% is best* So that is 36.4 oz or a hair over 3 of the little 12oz cans. Overcharging the system can reduce how cool the air is just as much as undercharging.
Of course it should only cycle whenever the low side pressure is lower than the switch is set for and the high pressure is higher than what the switch is set to trip at.
Snap ons service manual program says your low side switch should cycle on at 46 psi and shut off at 25 psi. If low side pressure is never getting below 25 and the compressor still cycles with the switch bypassed than it is probably a bad high pressure switch. As was previously mentioned you should never bypass a high pressure switch for any type of diagnosis except maybe for a system that will never engage the compressor. With that said scrap on says the high pressure switch is only supposed to cut off the compressor if high side pressure exceeds 410 psi and then resume operation when pressure drops back to around 150-250 psi. That high pressure cutoff seems pretty high to me so the data might not be 100% accurate.
I don't know if 87 does but my wife's 86 has a switch in the power steering line right above the steering box that is supposed to cut off the compressor when the power steering pump is under a heavy load in order to prevent stalling. Like when parking. Might check that switch out.
Hopefully this helps, if it doesnt help you then maybe it will someone else. It felt like it took hours to type this up on my tablet. Lol
Last edited by Blk91Firebird; 08-04-2017 at 11:50 PM.
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Re: A/C compressor issue or something else?
Also the compressor is supposed to have a pressure relief valve that blows at 440psi so I would try to make sure that didn't happen lol
I apologize if I repeated too much that had already been mentioned
I apologize if I repeated too much that had already been mentioned