1997 Blazer AC performance


Old 06-17-05, 09:36 AM
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1997 Blazer AC performance

My ac runs poorly. I have try adding a couple cans of R134a using the kit I have with a gauge. They do not seem to be pulled into the system well. Here is the symptoms-
1. compressor cycles on and off every 6-10 secs.
2. At rest pressure on the gauge at the dryer cannister (fill port) reads 130 psi.
3. When compressor on, high revs on engine, goes to ~18 psi.
4. At idle compressor on, ~25-35 psi.
5. after I try adding a can of refigerant, high psi went to 110 psi when compressor off.

So why am I not getting sufficient cooler as I got before?
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Old 06-17-05, 10:07 AM
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sounds like its still low on freon you probably have a leak also, and depending on how bad the leak is you may leak out what you have added fairly quickly.
you can try heating the can by placing it in warm water to get more freon out of the can, but the compressor will cycle alot if its still low once your low side gets up to around 35- 40 it will not cycle as much and will be easier to fill you basicly need more pressure in the can and warming the can will raise the pressure inside the can allowing it to flow increasing the rpm a little can help also once the system is getting closer to being full.
it will not start cooling until the system is getting close to being full you should see some cooling when your low pressure gets to around35- 40 a temp guage in the vent with a/c on max will help look for around a 30 degree drop from ambient temperature.
Old 06-17-05, 11:38 AM
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OK, will check and thanks for your help!
Old 06-17-05, 12:03 PM
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Just jump a wire on the pressure switch to make the compressor run all the time until you get another can in it, then hook back up the pressure switch and it should run.
Old 06-17-05, 12:29 PM
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you can try jumping the high side pressure switch or connecting the compressor directly to the battery to keep it on full time.
Old 06-17-05, 01:35 PM
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Originally Posted by zzzz1486
you can try jumping the high side pressure switch or connecting the compressor directly to the battery to keep it on full time.
You need to quit telling people this - it's useless advice and dangerous to both person and property. Hi-side pressure switch is normally closed anyway with A/C-on request to VCM. Even jumping the cycling switch on this system will do nothing if the VCM doesn't see the correct pressure and A/C-on request. Hotwiring the compressor is just stupid. The safeties and controls are there for a reason. It's also pretty obvious from the description that a low charge is the issue.

bejay is on track about warming the 134 cans. Even with that, you're going to be hard put to get a correct charge without evacuating the system (including vacuum), and adding to specs. This should also not be attempted without monitoring both hi and lo side pressures.
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