Automotive Air Conditioning Information Forum (Archives)

PITT412 on Thu May 28, 2015 7:15 PM

Year: 2003
Make: neon
Model: sxt
Engine Size: 2.0

Hi everyone,
new to the forums. I just finished installing a new ac evaporator core a few days ago, everything went well, no leaks and ice cold air. The only problem I am having with the ac is when I accelerate the compressor kicks off for a few seconds. I only added one 12oz can of r134 to check for leaks before adding the rest, so I know it is not overcharged. When I hook the gauge up to my low side port and and increase the rpm over 1,500 the pressure shoots up high then the compressor cycles off for a few seconds. What is causing this problem?

HECAT on Thu May 28, 2015 8:35 PM

No disrespect intended, but right now you are causing the problem; its undercharged.

You will need to vacuum and charge with full amount. Then provide the low and high side pressures.

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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

PITT412 on Thu May 28, 2015 8:43 PM

In the past when my system was undercharged the compressor would just cycle rapidly and the pressure would stay low. Now, when I accelerate the pressure increases alot then the compressor cycles. I believe the high pressure switch is turning it off. If the system is undercharged why is the pressure spiking so high when u accelerate? At idle the compressor stays on and delivers cold air.

I did not vacuum the system, but should have. I will probably replace the Accumulator, flush the liquid line/orifice tube and vacuum the system.

Edited: Thu May 28, 2015 at 8:47 PM by PITT412

GM Tech on Thu May 28, 2015 9:50 PM

You have air in the system causing the pressure spikes-that's what air does- always pull a vacuum!!!

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

HECAT on Fri May 29, 2015 5:05 PM

Quote
Originally posted by: PITT412
If the system is undercharged why is the pressure spiking so high when u accelerate?

I did not vacuum the system, but should have.

Yup.

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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf