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Ac compressor won’t start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Antoxen, Apr 14, 2018.

  1. Antoxen

    Antoxen New Member

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    2006 Prius with 350k had a hole in condenser which depressurized the system. I replaced condenser evacuated system and verified vacuum hold. Added nd-11 oil to line and soaked my 34a can in hot water. Added refrigerant to low pressure side only and compressor never cut on. I’ve tried to override the pressure switch but only cut the fans on. Please advise anyone. Thanks.
     
    #1 Antoxen, Apr 14, 2018
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Now that you have added some R-134a to the system, what is the pressure reading on the low side with the compressor off?
     
    #2 Patrick Wong, Apr 15, 2018
  3. Antoxen

    Antoxen New Member

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    Pressure got to 90 psig with the compressor off.
     
    #3 Antoxen, Apr 15, 2018
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    How long was the car left unrepaired with the damaged condenser? Is it possible that moisture got into the compressor and damaged it?
    How much refrigerant were you able to add? The spec for the refrigerant charge is 15.9 ounces +/- 1.1 ounce.
     
    #4 Patrick Wong, Apr 15, 2018
  5. Antoxen

    Antoxen New Member

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    4 months maybe. I may have an ounce in it if that. Is there any way to check if the compressor is done without playing the guessing game. I don’t believe in throwing parts at a problem. Can you check winding resistance to see if it is bad?
     
    #5 Antoxen, Apr 16, 2018
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It seems inconsistent to me that the system 1) had a vacuum, 2) had only one ounce of R-134a introduced, and 3) has a pressure in the system of 90 psi. I think there is a problem with at least one of these findings.

    Yes, you could measure resistance across the compressor windings. If they show any connectivity to body ground, that is bad. If the resistance readings across any of the terminals differs, that would be bad. The motor is three phase AC, so the measurement of each winding should be the same, and should be isolated from body ground.
     
    #6 Patrick Wong, Apr 16, 2018
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    This is something I'd like to learn about. I've repaired some of my other cars R134a systems, but never worked on a Prii system. Previously, after verifying the vacuum, I would just put the AC system on max and start charging refrigerant using 8 ounce cans. (Big Lots has 8 ounce cans of R134a with no additives or oil for $8 a can). Makes it easy to get close to the right charge. As you're charging, the compressor starts kicking on and off, eventually staying on once the suction (low pressure) cutoff stops activating. I don't think, at least in any of my previous work, that one ounce would be enough to even get the compressor to engage.
     
    #7 TMR-JWAP, Apr 16, 2018
  8. ChapmanF

    ChapmanF Senior Member

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    Have you tried asking the car yet? What's in the top left corner of the MFD if you put the car IG ON while holding auto + recirc together?

    -Chap
     
    #8 ChapmanF, Apr 16, 2018
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Now look at this...I'm about to learn something early today!!! I don't remember hearing of this previously. What information does it provide?

    Because, once I find out, I'll be experimenting on my car ASAP!!
     
    #9 TMR-JWAP, Apr 16, 2018
  10. ChapmanF

    ChapmanF Senior Member

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    Just a way of getting two-digit trouble codes from the HVAC, without having to lug out techstream.

    -Chap
     
    #10 ChapmanF, Apr 16, 2018
  11. Antoxen

    Antoxen New Member

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    I’m a pretty versed mechanic and all my readings are good. I did take resistance readings on each phase and got .08 ohms. Doesn’t say a lot because I don’t know how the motor is wired internally y or d wired. I did ask the mfd and got a 42 with a fwd arrow code. Tried to look that up with no avail. 90 psig should be enough to start the compressor. Idk. I do have 350k and just investing in a new compressor is a good idea regardless. Won’t do me any good if the compressor is not the problem though.
     
    #11 Antoxen, Apr 16, 2018
  12. Dxta

    Dxta Senior Member

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    Did you later on sort the problem out?
     
    #12 Dxta, Jul 6, 2018
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