AirCon - not cold, but compressor working?

[andrewwynn]

I didn't notice any change in airflow or fog when wife's x5!was freezing up the evaporator. I added maybe 7-8oz of R134a

Final low/high gauges. 45/245 psi. It was BRUTAL HOT over 90F so those are relatively high but fantastic results. 39F output at dash not recirculating with 90F outside.
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Do you have the final pressure numbers after the minor refill? I have a feeling it's just low still

This example was Lumba2 (wife's car). At about 15 years old original compressor, I have a feeling I had to slightly overcharge to get dashboard results. I think maybe 40/240 weird be closer to on spec. Even though it was hot as hell that day I was only getting 50F in the dash with low side 40. 5 now psi and it's been working better than mine ever since. I don't think I've had to recharge either mine or wife's since the initial recharge after purchased. (2 Summers)

[more_fasterer]

I didn't take note of the pressures after the extra gas was added. I'll take the car back there and see if bumping up the pressures improves things further.

[more_fasterer]

I did some more tests on the aircon system today, to better understand where the fault lies (I hate not knowing these things!!). The behaviour now is consistently showing that it can't cool the car when revs are low (<1500rpm) or when it's asked to do a lot of cooling.

Here are the results, using INPA to get the relevant figures:

• Ambient temp 27c / 80f
• Interior temp 30c / 86f
• In the best-case scenario, i.e. 5min with revs held at 2000rpm and the interior fan at 20%, the evaporator temperature only got down to 21c / 70f
• If the car was left to idle, or I pressed the "MAX" button on the IHKA control panel, the evaporator rose to match the interior air temp.
• The pressure sensor voltage stayed very consistent throughout, 1.9V +/- 0.1V.
• The left heat exchanger sensor sat at 14c / 57f and only varied by a couple of degrees during the test.
• The right heat exchanger sensor ran at the same temperature as the evaporator throughout.
• Both solar sensors remained at 0V throughout the test, with bright sunshine the entire time.

So, a couple of questions from me:

• What do Ze Chermans mean when they use the term "left / right heat exchanger?" Are these the left & right heater cores?
• Are the solar sensors meant to be 0V? There are no errors logged

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Given the pressure levels are in range, yet the pressure sensor barely budged throughout, I reckon this is leaning more and more towards the variable compressor being stuck in its minimum compression setting. I've got a professional turning up on Thursday, so I'll ultimately leave it up to him to sort unless he starts sounding fishy.