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Joined: Mar 2002
Posts: 496
CEG\'er
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CEG\'er
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http://www.ackits.com/
Go here and spend some time reading up on the subject, in the automobile A/C forums. Ask questions here, there is a guy named Chick who usuallly answers any questions quickly.
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Joined: Oct 2004
Posts: 1,456
Hard-core CEG\'er
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Hard-core CEG\'er
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Do you mean on at 45 and off below 25, you have low R134A. Make sure it's warm out when testing (probably is where you are  ). The pressure drops at first and stabilizes when the compressor runs. If it drops too fast and too low the switch in the accumulator will turn off the compressor. Then the pressure rises and the compressor will run again, and go off quickly...
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Joined: Jan 2002
Posts: 753
Veteran CEG\'er
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Veteran CEG\'er
Joined: Jan 2002
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There's a pressure switch on top of the accumulater, it could be bad. My A/C had the same symptoms and it was that switch. It costs about $15.
Dueling Duratecs
'95 SE V6 MTX 0 Mods
'04 Mazda6 S Wagon
'03 Kawasaki Z1000
But thus do I counsel you, my friends: distrust all in whom the impulse to punish is powerful!
Friedrich Nietzsche
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Joined: Sep 2002
Posts: 1,788
Hard-core CEG\'er
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Hard-core CEG\'er
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If the compressor clutch is short-cycling the switch is fine. The refrigerant is just low. Whent he cycling switch fails, it usually causes a no-engagement condition.
With the system OFF, underhood temp at around 60-80F, you should show around 70 psi or so (static pressure). This pressure changes with the ambient, so it will be hight if the under-hood area is hot or lower if it's cold.
Steve
98 Contour SE Sport 2.5 Duratec ATX The wifey's car
89 Taurus SHO - 246K miles
94 SHO ATX - 190K
1997 F-150 5.4L ATX - The Workhorse 150K.
ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
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Joined: May 2000
Posts: 3,290
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: May 2000
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Originally posted by projectSHO89:
With the system OFF, underhood temp at around 60-80F, you should show around 70 psi or so (static pressure).
Thanks, does that refer to the high side?
E0 #36
'95 Ranger
'82 Honda CX500
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Joined: Jul 2001
Posts: 3,037
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: Jul 2001
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Hey, when mine was short cycling, it turned out to be a wiring problem. Just a thought.
"Think of it, if you like, as a librarian with a G-string under the tweed." Clarkson on the Mondeo.
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Joined: Sep 2002
Posts: 1,788
Hard-core CEG\'er
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Hard-core CEG\'er
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Originally posted by Viss1:
Originally posted by projectSHO89:
With the system OFF, underhood temp at around 60-80F, you should show around 70 psi or so (static pressure).
Thanks, does that refer to the high side?
When the system is static, the pressure is the same everywhere in the system...
As for a "wiring harness problem" causing compressor short-cyling, I'd have to see the exact failure mode in order to explain that idea.
Steve
98 Contour SE Sport 2.5 Duratec ATX The wifey's car
89 Taurus SHO - 246K miles
94 SHO ATX - 190K
1997 F-150 5.4L ATX - The Workhorse 150K.
ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
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Joined: May 2000
Posts: 3,290
Hard-core CEG\'er
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Hard-core CEG\'er
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Thanks again for the responses. Static pressure was around 30. Outside temp was about 75, underhood probably a little higher. Keep in mind that I'm just going by what the gauge on the can says, so it might not be accurate.
The compressor no longer engages at all. I'm thinking whatever R134 was left in the system escaped when I tried to add some the other day.
Seems to me it's probably a leak, since the compressor was operating fine the other day. Is there some way I can add R134 now though just to see if the compressor will operate again?
E0 #36
'95 Ranger
'82 Honda CX500
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Joined: Sep 2002
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Hard-core CEG\'er
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Hard-core CEG\'er
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The pressure supplied by the can is what will re-engage the cycling switch. The switch should close at around 45 psi ascending.
Pick up a can of R134a with V dye so you can find the probable leak. Throw a can of that into it and then inspect all the plumbing with a UV light paying particular attention to all the fittings.
Steve
98 Contour SE Sport 2.5 Duratec ATX The wifey's car
89 Taurus SHO - 246K miles
94 SHO ATX - 190K
1997 F-150 5.4L ATX - The Workhorse 150K.
ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
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Joined: Oct 2004
Posts: 1,456
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: Oct 2004
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Watch for bubbles around the threaded base of the service valve where you put in the 134. Problem spot for me (until I get around to fixing it and check for leaks with the dye and a refrigerant sniffer bought on ebay . Also, the accumulator might have rusted out behind the foam rubber, happened on our other Mystique.
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