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Anyone Good With A/C Systems


Bark

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I have a couple cars that have a/c issues and Id like to get them taken care of. I would do it myself but I dont have the gauges or a pump to evac the system. Not exactly sure whats wrong but i have a focus that short cycles when you turn the a/c on and it will not take any regridgerant. The other is a grand am and I think it might be the compressor clutch (its pretty loud). Is there anyone around good with a/c systems that wouldnt mind taking a look and hopefully fix the issues. Let me know your price!
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IIRC, short cycling is caused by the high side having excess pressure, which triggers the pressure cutoff switch and disengages the compressor's magnetic clutch. Pressure then drops, which re-engages the clutch and it flip-flops between the two, hence short-cycling

 

Excess high side pressure is usually caused by overcharging the system with refrigerant or air being in the system.

 

My memory on the Focus is a tad fuzzy, but I do recall my niece's 03 Focus being difficult to deal with as one of the service fittings required going through the fender skirt to access.

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Yes exactly. I had to go through the passenger side fender skirt for access to the low side port. It wouldnt take any refrigerant so maybe the high side was over pressured. Although when I started I had no pressure on the high side. After hooking up the low side to a charge the compressor kicked on and short cycled but it wouldnt take charge
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usually a compressor short cycling has a low charge. If the compressor is loud on the other system it is probly bad. When gm had the old wobble plate compressor i replaced alot of them. early 90's through late 90's
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Too low of a pressure and it should not cycle or not very often. If it has a minimum pressure sensor/requirement, it may not even energize the clutch on the compressor.

 

Rapid cycling is from too much pressure. Simple fixing, you can let it out till it runs long enough for you. But ultimately without recovering and vacuuming the ac system to get out refrigerant and all other gasses or moisture, you won't see great results.

 

With the car sitting with a/c and engine off, get some ac gauges and check where the static pressure is. Both sides should be equal pressure and the pressure you read should be compared to a r134a temp/pressure chart. You can learn a lot from your gauges.

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It has been my experience that most A/C systems typically are either inproperly charged or have a leak (not to say thats it). So the first thing I do is make sure the system is properly charged. This takes the proper equipment. This does not mean it will fix it but it's where most cases should start. This is also why buying shitty little cans of refridgerent at the auto parts store and ramming them into your A/C system and seeing what happens is fucking stupid. I really wish people couldn't buy those. How does anyone expect to diagnose the system when there are variables they don't know? Take it to someone with the correct tools. Maybe its a charge problem, maybe its moisture, maybe its the compressor or the sensors controlling it, but you won't know anything until you've checked for leaks, verified that it has the correct charge in it, and then see if the sensors are reading correctly so you can properly and accuratly diagnose it from that point.
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+1 for Cordell. The sheer amount of ham-fistery that occurs as a result of a parts store should warrant mandatory contraceptive use so such people are unable to reproduce :gabe:

 

A few weeks ago, I was at the local Advance Auto and some guy swore up and down that the reason one (not both) of his high-beam headlights wasn't working was because the relay was kaput...

 

This is why I forced myself to learn every detail of the car in order to make sound, logical choices on everything that goes into it. Automotive Literacy is a good thing :)

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It has been my experience that most A/C systems typically are either inproperly charged or have a leak (not to say thats it). So the first thing I do is make sure the system is properly charged. This takes the proper equipment. This does not mean it will fix it but it's where most cases should start. This is also why buying shitty little cans of refridgerent at the auto parts store and ramming them into your A/C system and seeing what happens is fucking stupid. I really wish people couldn't buy those. How does anyone expect to diagnose the system when there are variables they don't know? Take it to someone with the correct tools. Maybe its a charge problem, maybe its moisture, maybe its the compressor or the sensors controlling it, but you won't know anything until you've checked for leaks, verified that it has the correct charge in it, and then see if the sensors are reading correctly so you can properly and accuratly diagnose it from that point.

 

well said!!

 

to my knowledge their trying to restrict the R134a cans so anyone WITHOUT ASE a/c certification will NOT be allowed to buy them.

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