Automotive Air Conditioning Information Forum (Archives)

Serapium on Sun July 24, 2011 6:27 PM

Year: 1995
Make: Dodge
Model: Neon
Engine Size: 2.4
Refrigerant Type: R-134a
Ambient Temp: 100
Pressure Low: 45
Pressure High: ?
Country of Origin: United States

Greetings! I'm new to the board, and am just knowlegeable enough about mechanical issues to confuse myself when I dig deep.

I've got a '95 Neon with an odd A/C issue I'm having trouble digging up details on. When the motor is running at idle, the compressor kicks on and runs fine. A/C blows cold, and low side pressure reads about 45 on my amittedly cheap guage set. When the motor is at higher RPM's the compressor will kick on for about 5 seconds periodically (about once every 30 seconds) and when it is on the A/C blows cold. Problem is the other 25 seconds When the compressor kicks off my guage pegs out, but it only goes to 95 so I'm unable to tell what the actual pressure is. Ideas on where to start? Thanks-

TRB on Sun July 24, 2011 7:37 PM

Your low side pegs at 95?

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Serapium on Sun July 24, 2011 8:40 PM

Yep. As soon as the compressor shut off the pressure reading on the low side spikes WAY up. Guage only goes to 95, so I'm not sure how high it's actually spiking. When the compressor re-engages the pressure drops slowly back down to 45. Seems like as soon as the pressure reaches 45 is when the compressor shut off. At idle the pressure never drops below about 48 or so, and the compressor remains engaged.

JJM on Sun July 24, 2011 10:11 PM

You need a real set of gauges to properly diagnose an A/C... otherwise it's diagnosis by wigi board and tarrot card, throwing parts (and money) at the problem needlessly.

You can pickup an inexpensive gauge set from the site sponsor like this:



66773 - Mastercool "DIY" Special (66773)

Plus, the site sponsor is running an awesome sale.

Post back with complete pressure readings and we can take it from there.

Joe

TRB on Sun July 24, 2011 10:33 PM

Agree with Joe on getting proper gauges for starters. Since you have the suicide kit. Can I assume you have added refrigerant? Any sealer been added to the system? Are your fans working when you turn on the a/c?

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Serapium on Mon July 25, 2011 12:21 PM

Will invest in a proper guage set when I can afford it.... I was just hoping that a pro would have an obvious answer for me. To answer your question, yes I have added refrigerant, but no sealant. Just staight R-134a. At the time that I added refrigerant the system appeared to be working properly, and cooled well under all conditions for about 3 weeks. At that point the compressor was cycling 'properly' and low side pressure stayed consistent at or near 45. The change to its current state was a sudden development, not one that worsened over time. The fans do work when I turn on the A/C, and I have no problems with overheating.

JJM on Mon July 25, 2011 11:27 PM

Compressor shouldn't be "cycling" at 100F unless the blower motor has stopped. That's why we need full pressure readings, low and high side. It's possible your high side is tripping the HPCO, but we can't know that wthout high side readings.

Joe