A/c help

[Derailed]

Guys I have a 96 318is that I swapped a m52b28, i just installed a full replacement system used except for the condenser.
So I charged the system by opening the relay and closing the circuit for the compressor, I put 3 12oz r134 cans of Freon and 6 oz of pag 100 with leak dye.

The system has charge 35psi but the compressor relay will not close/engage to power the compressor .
Replaced high pressure sensor, ambient temp is reading +84 f.

I have digital climate control and it does turn on the aux fan, swapped relays between the compressor and fan as they are the same and no change.

Only other note is I have fdm please help it's starting to get warm with these leather seats

[Eric93se]

Here is a charge reference sheet to go by. I hope you dumped out all the old oil and blew the lines out.

[Eric93se]

I hope your reading both hi and low pressure sides.

[XnWarden]

It doesnt sound like you charged it properly. It sounds like you used the "AC pro" stuff from an auto parts store. Those are meant to top off the system, not to do a total refill. You need a real set of ac gauges to accurately read the pressures. The low side pressure of 35 psi is only part of the story. In order to do a proper job, you also need a vacuum pump to check for system leaks and evac all the moisture from the system prior to refill.

In regards to your specific problem of the compressor not engaging, try manually jumping power to the switch on it. The junction box on the passenger side is a good source of 12v. Run a wire with alligator clips to the clutch switch on the compressor.

Did the compressor cycle on at all at any point during the refill? Did you double check the connection at the pressure cutoff switch on the receiver dryer?

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[Derailed]

Yes I did just use the low side port to charge, and the compressor does work with the relay i opened up closed the circuit.
I do not have the manifold gauges so I guess my best bet it to a ac shop and have it be correctly filled.
Thanks guys I just assumed it was something that needed replacement, didn't think I was using the wrong fill procedure I will go to get it charged and update

[marvinstockman]

With the engine off and cold, what are your static pressures. If you read 35 psi, then your system is undercharged, but you say you added three 12 oz cans, which means it should be close to fully charged. At 85 F outside temp, your static pressures should be in the 90's. Remember, static means nothing on and engine cold.

[XnWarden]

Agreed. The pressure switch will only kick the compressor on once target pressure has been reached. During recharge, the vacuum drawn on the system sucks the r134 in until sufficient pressure is reached to cycle the compressor on and draw the rest in. You may have a leak somewhere, and/or the refrigerant may not have entered the system if no vacuum was drawn.

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[Eric93se]

You can do it yourself but you need full gauges and a vacuum pump. You should have put new o-rings as well. You will save a lot of coin doing it yourself but you have to read up to do it right.

[Derailed]

Found this thread and looks to be what my problem is dme was delete related so time another dme and might as well go for a tune.
Has the same swap as I did and ews delete
https://www.bimmerforums.com/forum/s...er-engine-swap

[eliseogonzalez]

BTW auto one will rent the gauges and vacuum pump for 300 total and u get full refund upon return. You do need to provide your own pump oil however.

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BTW here is a video on using the compressor and gauges

https://youtu.be/Pdq8JAlct6s