AC compressor cycling. mk2 diesel

Discussion in 'Styling, Trim and Bodywork' started by 93Ford, May 26, 2022.

  1. 93Ford New Member

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    Is there a thermostat or control unit that will make the compressor cycle on and off. From what i can tell in the mk2 ac systems theres the pressure sensors that are just a safety switch so the pressure isnt to high or low and thats it. I believe my car might have the mk1 style system someone put in as theres no expansion valve where is comes through the firewall instead the ac lines go into the firewall. In the mk1 system the expansion valve is on the evap under the dash somewhere. Are the compressors supposed to cycle in these old systems. The only thing i could find in the parts diagrams is theres a thermostat in the ducting somewhere is that what controls the cycling.
     
  2. davidut5 Forum Member

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    Yes, if it has a thermostat, and vaporizer is about to ice up it will cut the compressor power. Another reason could be overpressure from insufficient cooling, the safety switch will cut compressor power, guessing at or over 30bars
    Put the blower on full speed see if it still cycles.
    Do you have relay number 13 or 140 in position 1(for ce2)? I read some solder joints in the relay need redoing as they crack over time.
     
  3. 93Ford New Member

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    I believe i have a ce1 (1985). The ac system in this car has me all kinds of confused its some kind of rare in between year or custom rig i have no idea. It has the normal mk2 heater box but the ac box section is different normally the blower fan is facing torwards the passenger but instead this one is facing torwards the ground. The expansion valve is right on the evaporator inside the cab like the mk1 system and the ac hoses go into the firewall and connect to it there. The ac hoses are custom and of course they forgot to put a low pressure port in the hose. Currently there are no pressure switch in the system. I think what im going to try is to get a new dryer and get a low pressure port in there fill it up and see if it works if it doent then im not going to worry about it anymore as parts seem to be literally impossible to find.
     
  4. davidut5 Forum Member

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    Non ac blower have the motor facing down.
    It should have at least one pressure switch, if it looses refrigerant to cut power to compressor.
    Could be some king of aftermarket kit you have installed.
     
    Last edited: May 29, 2022
  5. 93Ford New Member

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    It being some kind of old aftermarket kit is the only thing i can think of. I was going to use a vintage air dryer with the pressure switch on it but yea currently it has no switches on it. It seems to be quite the rig someone has put together.
     

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