AFASTYZFR1

iTrader: (55)

Today I got a/c gauges and vac pump and just checked system a little bit. A/c still has 10" of vacuum since 7/17 (we discharged system and left it with vac on it). So it must not have any leaks. Guess the next step is to vacuum system more and try and re-charge?

fleetmgr

Yes, but to do it right you need to weigh the charge.

AFASTYZFR1

iTrader: (55)

I put in 1.5 lbs(24oz) of 134a after pulling a steady 30" of vacuum for over 2 hours. It held that vacuum for about an hour before I re-charged it. Here are the videos of it working perfectly. Air is blowing cold and compressor is not cycling. I will let car sit for an hour and try it again and pray it still works

Gauges right after adding 24 oz of 134a:



Gauges right after shutting car off:



Gauges an hour after shutting car off:



Going to start car and check ac. Will post update.

HotSilverBird

Did you replace the transducer?

AFASTYZFR1

iTrader: (55)

At idle compressor cycles after letting car sit for an hour. AC still blows cool air (not cold). Here is video of whats going on.......please help




If I hold rpms up, compressor stays on WTF

AFASTYZFR1

iTrader: (55)

No, whats that...haha

Is that the temp sensor inside the car?

HotSilverBird

The pressure transducer that the pcm gets it info from, it mounted on one of the ac lines.

AFASTYZFR1

iTrader: (55)

If you are referring to the pressure switch by the shock tower, I am going to borrow the one off the black camaro in my garage.

HotSilverBird

Thats not a pressure switch........its a transducer...the computer uses the info to control the compressor.

fleetmgr

And, if you have to change it, you'll have to blow the charge and re-evacuate the system.

AFASTYZFR1

iTrader: (55)

Does that seem like it could be the problem? Any way to test it with a multimeter?

fleetmgr

Have you stuck a thermometer in your center dash vent and measured the actual air temp? If not, then I would do that.

Your gauge pix (with one exception) don't show much, due to out of focus.

AFASTYZFR1

iTrader: (55)

I haven't done it in center vent. Yea, digital camera was focused on ac gauges and wont re-focus during recording. I will check that this afternoon.

AFASTYZFR1

iTrader: (55)

Also one thing I forgot to mention was that even after system being completely empty with a vacuum on it, I did not have to jump wires or anything to get compressor to kick on and pull refrigerant in. So maybe pressure transducer is bad and reading high which let compressor turn on with empty system and cuts it off from thinking there is too much pressure with system filled?


I don't know......guess I just need to replace it

slow

iTrader: (7)

what do the pressures do when the system cycles?

The system will disable the compressor if the pressure goes over 414 psi and it will re enable the system when the pressure goes under 249 psi.

If the pressure is under 34.9 psi the system will be disabled and if pressure is over 39 psi the system is enabled.

If the voltage is below 10 volts the compressor is disabled. If the voltage is not at least 10.5 volts the comoressor is not enabled.

The compressor clutch will be disabled if the ECT goes over 125C

These are just a few of the functions that determine of the computer will cycle the system. Do you have a datalogger that can log the AC pressure?

Ryan

AFASTYZFR1

iTrader: (55)

As it cycles low pressure drops from 75psi to 60psi when compressor kicks on and rises back to about 75psi when it kicks off. Overall psi drops the longer I let it keep cycling.

High pressure rises from 200psi to 220psi when compressor kicks on and falls back to 200psi when compressor kicks off


I have a set of ac gauges to log pressures which I posted videos of above. I have access to hp tuners also.

slow

iTrader: (7)

connect hptuners and datalog the AC pressure, and see if matches your gauges, if it does, then it should rule out the sensor being bad.

also log engine speed, TPS, and battery voltage, since those are items that are used in the AC logic of the pcm. Can you also log "ac clutch" status, to make sure the pcm is commanding the compressor on and off.

Something I fought on my 98 ws6 for a couple of months was a bad connection on the AC compressor itself, I would command it on with a tech2 and it would work sometimes but not always. I disassembled the connector, replaced the terminals and it worked great. Using hptuners you can command the compressor on, and see how the system works, (overriding the pcm base logic to enable the compressor)

Ryan

AFASTYZFR1

iTrader: (55)

Still haven't had a chance to scan it with HP Tuners, but I just noticed today it wont cycle as long as blower speed is < or = to position 3. As long is it isn't on max blower speed it wont cycle......any ideas with new info?

HotSilverBird

what is the pressure ion the low side doing when its cycling on max.

AFASTYZFR1

iTrader: (55)

Around 35 psi. All the videos above are of the pressures on max.