cocobeex

2017 Summer, AC button was flashing then, it turned off my itself. I went back to the shop, found out the Tech didn't properly install AC piping back after turbo upgrade 2017 Apr.
All freon was leaked out.
The tech fixed the AC 2017 summer. It was working 2017 Summer till 2018 summer.

2018 Summer, As soon as i turn on AC, car drives funny. It goes weak and Engine runs rough. exhaust sounds rough too. (Sounds like exhaust leaking)
Car would also bucking, after let go of gas pedal.
During this issue, turning off AC won't get car back to original power back. I have to turn off the car. reset ECU.

I have checked on google.
Search results are saying,
1. AC compressor might be dying. (But it still makes cold air.)
2. Freon is low.
3. too much Freon
4. Engine Issue (I dont think this is the issue, since its running strong without AC on)

Any possible reasons this issue was caused from "The tech who didn't hook up my AC properly after turbo upgrade" ??
I heard some people said, compressor might get damaged if the AC piping isn't connected properly.

Any thoughts ?

kajtek1

The only way I can figure out for your AC affecting engine run is compressor grinding the internal parts and putting big resistance on the engine.
Take the belt off and try to move it by hand.
And as always - you should start with reading the codes.

cocobeex

Thank you for the heads up!!

I have also scanned the car by obd2 tools, and xentry. No codes showing.

kajtek1

When you have to reset ECU - you have to have a code.

cocobeex

I did scanned it.
But i really dont see code showing.
After i resets it. It drives fine.

Thats very strange.

kajtek1

You do have MB-oriented scanner?

cocobeex

Yes, I do MB Star System, Xentry...etc

Clement63

I had a somewhat similar issue - engine ran rough during start up and air con was not cool but once start moving it slowly gets cooler and engine is not so rough. Turns out I had a broken Belt Tension-er ; this is basically a pulley that had some plastic element within that had broken..thus insufficient belt tensioning to drive the air-con compressor when idling or start-up...

Arrie

There is another way compressor can make engine run rough. If your refrigerant fill is way too high the compressor starts to press gas form directly to liquid for, which should not ever happen. From gas to liquid should happen only in the radiator in front of the car.

kajtek1

Those AC systems have high pressure limit switch, so overcharge would fluctuate the load.

cocobeex

WOW!!! thats scary. I will definitely check it.

cocobeex

With in issue, when I turn off AC button, it still blows cold air for about 5-6 mins or longer.

I remember, before this issue, as soon as i turn AC button off, it will stop cold air in 1-2 mins.

I guess the only way to find out overcharge, is to hook up to the gauge.

kajtek1

You said, you have good scanner. Why not use it?

cocobeex

Double Post - Delete

cocobeex

I did!! I scanned it with xentry.
Also with obd2 scanning tool.
Both No codes showing
It's a very strange situation.

If there is code, I would have post it here.
But no code showing at this moment.

This Saturday, I will dig into it.
1. Use gauge to see if it's over charged or too little Freon.
2. Check belt and tensioner.
3. See if anything is grinding on the compressor unit.

Arrie

You may have an issue with the expansion tube/valve. If it plugs up your high side pressure goes very high and if bad enough can turn gas to liquid at the compressor and definitely would rob lots of power from the engine. High pressure sensor should pick this up and cut it off but if the sensor is bad and does not see the excessively high pressure then the system cannot protect itself.

cocobeex

I might just take whole compressor out, check the tubes and valves. Then do a clean install.
Sounds very time consuming.

Thank you so much for the info!!

kajtek1

Your scanner will read all AC sensors.
I keep posting link to procedure, but for starters, you need to test sensor calibration, meaning reading them on cold morning.
Than 2nd time read the sensors on hot afternoon, when AC should work at max.

cocobeex

I see!!! Looks like i didn't go deep enough with Xentry !!!
I will go in AC category and test sensor calibration.

I will post screenshot if i can later.

Thanks for the info!!!