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Discussion Starter · #1 ·
This is a '94 which uses 134a.

I replaced a line on the pass side because it was too close to the header and eventually fail and released all the refrigerant. I charged it throught the low press. side with a DIY kit. It worked fine for another year.

Now the compressor won't engage for more than a couple seconds so I check the pressure. High side reads 75psi and low reads 50psi. I hooked up a new can of 134a but it's not charging.

what could be wrong?
 

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Did you put it in a vacuum before you charged it the first time?If so you might try jumping the low pressure switch to keep the compressor from short cycling while it charges enough to keep running.And are these pressure readings with the compressor off or on?
 

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Discussion Starter · #3 ·
gm2bad said:
Did you put it in a vacuum before you charged it the first time?If so you might try jumping the low pressure switch to keep the compressor from short cycling while it charges enough to keep running.And are these pressure readings with the compressor off or on?
No I didn't. How do I put it in a vaccum? would it help? The readings would be with the compressor off because the compressor clutch never engaged long enough for me to read it while running.
 

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If it pulls down below 20-25 psi on the low side the low pressure switch will cut the compessor off by disengaging the clutch. This really sounds to be your problem due to an undercharged system. It is a must to pull a vacume on any system that has been open before recharging. First pulling a vacume boils moisture from the system, secondly you can test for leaks(if it wont hold a vacume it wont hold pressure), And thirdly it removes air from the system that has a different thermal expansion rate than refrigerant does which will cause pressures to be erratic and ineffecient cooling due to system not being properly charged.
 
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