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2003 Honda CRV - Need to Confirm Expansion Value Issues

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  • 2003 Honda CRV - Need to Confirm Expansion Value Issues

    Hi All,

    I've recently run into issues with the AC system in my Honda CRV. To start, the AC clutch engages and blows cool for the first 20 seconds.

    Low Pressure Side Reads: 40-50 psi
    High Pressure Side: Starts at 150 psi and climbs to 190+ psi (my high side stops counting beyond 190)

    Low side doesn't climb beyond 50 while AC clutch is engaged

    After the AC clutch disengages:
    Low Pressure Side Reads: 75 psi
    High Pressure Side Reads: 180 psi (this holds steady)

    AC Clutch attempts to reengage without success and this repeats every 10 seconds or so.

    The research I've done so far leads to an issue with an expansion valve. Could anyone confirm my suspicion?

  • #2
    So far, to me, this does not look like a problem related to the expansion valve, But I would really like a little clarification here on these two points you made...

    my high side stops counting beyond 190
    AC Clutch attempts to reengage without success and this repeats every 10 seconds or so.
    Are you saying your gauge isn't able to display pressures over 190psi?
    What gives you the impression or indication the clutch tries to re-engage every ten seconds?

    Thanks,

    Chris

    Comment


    • #3
      Thank you for your response Chris!

      My high side does not display pressures above 190 psi, that's where the gauge stops counting.

      I can see the AC clutch attempt to re-engage, it starts to spin for a moment and then stops. There's a high pitch whistle that starts when it attempts to re-engage as well. So I'm just watching the AC clutch and I can see it attempts to kick in.

      Thanks,

      Camden

      Comment


      • #4
        You need a different gauge! A/C systems can reach pressures near 400 psi.
        I agree with Chris, it does not look like an expansion valve issue. We need to know how high the high side is going, My guess is the high side pressure is much higher, and the system safety is shutting it off until pressure hits the high limit again.

        Comment


        • #5
          O.K., Camden. that helps! I would be worried that the pressures are very high and what you are seeing is the compressor kicking out at the high pressure cut-off point. Without a proper high side reading we couldn't be sure, but, it sounds like a good possibility. This system could be hitting 400-450 PSI and you wouldn't know it. You have to check to make sure you have condenser fan operation. If there are no cooling fans providing good airflow across the condenser during compressor operation, high side pressure can build very quickly. Overcharge, bad refrigerant, high side restriction are some of the other things that could be in play. Just be careful since you can't properly monitor high side pressure. You don't want to be around a system that is running excessive pressure.

          When expansion devices fail, they generally restrict the flow of refrigerant too much, which you would generally see as a very low suction (low side) pressure.

          Comment


          • #6
            Awesome, thank you both for your responses. It sounds like you both have a similar proposal about what's going on.

            I noticed a small amount of refrigerant that was building up on the strut tower right below my high side port. The manifold gauge set is brand new and the fittings should hold up reasonably but considerably high pressure might cause that fitting to leak slightly.

            All of this being said, could I get away with checking to see if the condenser fan is operational or not before getting another manifold gauge set that can read higher psi? If the condenser fan is not operational, is it reasonably safe to assume that the issue could be resolved with a new condenser fan?

            Comment


            • #7
              I believe on that model, the fan(s) should run anytime the compressor is on. So as long as you don't let this pressure go over 190 where you can't safely monitor it I would say it would be pretty easy to check. Compressor on = fans on. Compressor off = fans off. Now, if it is a fan problem, it may not be the fan itself, but it could be something related to that circuit. I think checking for fan operation would be the first place to start. Let us know what you find.

              Chris

              Comment


              • #8
                Alright, kicked on the AC for about 10 seconds, the AC clutch engaged the compressor and the condenser fan did not kick on. Attempted this twice with the same result.

                Would the next step be replace the condenser fan then get another reading of high and low while the compressor is engaged?

                I forgot to mention the climate when stating my high and low pressure readings. I took them at 72 degrees F with 65% humidity. I used a general low/high pressure chart that recommended 25-37 psi for low and 83-155 psi for high. Should I follow these ranges after installing the condenser fan?

                Comment


                • #9
                  With no airflow over the condenser it is shutting down from over pressure. Do you know the fan is bad, or is it a relay or circuit breaker? you need to do more diagnosing
                  Be very careful around a system esp if it is reaching the high pressure cut off point. A burst hose can blind you permanently, and even if doesn't get it you eye, can cause bad burns. Nothing to fool with.

                  Comment


                  • #10
                    Sounds good Corn. I'll need to research means of testing relays and circuit breakers.

                    And since you both have mentioned the dangers of high pressure I've been working with extreme caution, proper protection and engaging the AC system as little as possible. I appreciate your warning.

                    I will continue with diagnostics over the next few days since I'll be busy with work but I will continue to post updates here.

                    Comment


                    • #11
                      Great, now we know the fan isn't working. This could explain a lot. Though I would not want assume the fan motor is bad without doing a few more checks. If it's not locked up, you probably want to start with a wiring diagram and test light to see if you are getting power and ground to the motor. Some people prefer to go straight to disconnecting the fan and putting 12 V power and ground to the fan to see if it spins. If it does spin with power and ground applied, then you have to dig deeper and start checking relays, fuses, switches, wiring, etc.. I don't often see bad Honda fan motors, so, my workflow would start at the fuse box after all my visual checks. If it had a Bosch style relay I would probably remove the fan relay and jump pin 87 and 30 to see if the fan works. But because I'm really not sure off the top of my head what the wiring looks like in that Honda so I might just go straight for the wiring diagram.

                      As far a charging, the charge charts are useful but I usually have the luxury of charging by weight. The one thing i don't like is your low ambient air temperature. I feel that it's easier to overcharge a system using a chart when temperatures are that low. 75 degrees F ambient temperature is my minimum for using a charge chart. Those specs you listed are fairly broad, but look reasonable. Most vehicles have a published charge specification and charging by weight is my preferred method, especially with these smaller systems which have less room for error. The chart should keep you in safe territory though. Just go slow and be patient.

                      I use charge charts mostly on buses and fire equipment. In that realm, charge charts are only factoring high side pressure and air temperature in front of the condenser. You add or subtract refrigerant to reach the desired high side pressure based of the ambient temperature pulled into the condenser. It's slow and methodical. Charging by weight means less time getting pressures to equalize and less tweaking in general. Charging by weight also means you can fill a system at low temperature and be sure it's not overcharged.

                      Keep us updated...

                      Comment


                      • #12
                        Alright, getting back to work with the Honda. I'm going to head over and pick up a circuit tester, something like this: https://www.amazon.com/JASTIND-Autom...omotive&sr=1-3.

                        Do either of you have any reading/video material that you would suggest on checking relays, fuses, switches and wiring? I think I have a fair understanding about how to use a circuit tester but would like to learn more about electrical diagnosis overall.

                        From what I can tell from initial readings when the AC compressor engages, the system seems to be reasonably charged. I had a few family members recommend just adding more refrigerant and I'm glad I took the time to continue diagnosing. I will know more when the condenser fan is functional but I think I'm doing well on refrigerant levels.

                        Comment


                        • #13
                          Quick update: I ended up working with a multimeter as well as just hooking 12 V directly to the condenser fan.

                          12 V to the condenser fan didn't spin.
                          Checked the voltage that was feeding to the condenser fan and it was pushing 12 V.

                          So, I'm going to remove the condenser fan, examine the components and hook it up to 12 V. If it still doesn't spin, I'll order another one, install and check the low and high side readings and continue on.

                          Comment


                          • #14
                            Sounds like your on the right track, Got to get air over the condenser.

                            Comment


                            • #15
                              Sorry for the delayed update. Replacing the broken condenser fan did the trick! AC blows cool, pressure readings on low and high side look good. Total spending on the project was $40 for the manifold gauge set and $52 for the replacement condenser fan. I really appreciate all the assistance and everything I've been able to learn along the way. This has turned into a hobby for me and I'm excited to see what else I can learn and achieve.

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