Hi All,

I bought a 93 cherokee sport a half year ago and the guy told me the
ac does not work. I checked the repair records and saw a r134a
conversion and charge by a professional in 2004. I tried charging it
myself today. I located the low pressure port (bottom one on the back
of the compressor with blue cap). First the system wouldn't except any
gas, it just made the dial on the can of coolant shoot up and then the
connector would hiss off when I removed it. Hmmmm, noticed that the
compressor didn't turn on. Checked the forums and found out to jumper
the low pressure switch. I was pleased to note that the compressor
runs. However, when I connected the 134a coolant, expecting it to suck
it up the gas, it once again did not seem to want to accept gas. Is
there another valve that I need to open? Does anyone have any
suggestions for how to trouble shoot this? I figure that I would just
waste cans if I had a leak. That is why I think this behavior is kind
of odd. I'm probably missing something easy here.

Thanks for your help.

Best,
Breton

On 7 May 2007 10:20:38 -0700, breton <bretonh (AT) gmail (DOT) com> wrote:


If you want to do this yourself properly I suggest you borrow, rent or
buy a set of gauges for R134 systems ans see what pressures you
actually have when compressor is running.
-----------------
TheSnoMan.com

I am thinking that the Schraeder valve in your low side coupler is worn or
broken. I assume that you have one of those Autozone or similar "recharge
kits" with a low side coupler, a gauge and a combination can tap needle
valve. Correct me if I am wrong. With the valve off, you should be able to
connect to the low side coupler and read some pressure, unless it is
completely discharged. Now with the needle valve can taps, it is necessary
to screw the handle in to pierce the can, and then screw it out to release
the refrigerant into the system. Are you doing this? In Usenet, it is
necessary to ask, so don't take this personal.

If you have low pressure then you definitely have a leak in your system.
The problem I ran into in my Suburban is that AC repair jockeys would find
one leak, say, "That's it", and leave the rest of the leaks for the next
repair jockey to find. After paying for AC service two or three seasons in
a row, I got wise, bought my own gauges, replaced all the O-rings in the
system and the rear AC hoses that were actually leaking, and it is still
working after four seasons of moderate to heavy use.

Earle

"breton" <bretonh (AT) gmail (DOT) com> wrote

breton wrote:

STOP right there!

You used the high side port. The connector off the compressor is
the high-side no matter what the cap color is.

The low side is between the condenser and the evaporator. The
smallest line in the system that runs from the firewall.

What bugs me is the connector should not have fit unless the
shop that did the mod buggered something up.

--
DougW

If it's a Sanden compressor, it can have the low side port on the
compressor, or even both low and high side ports on the compressor.

Also, the smaller of the two lines, is always the high pressure side.

The low pressure line is always the larger diameter line.

Spdloader

On May 7, 6:06 pm, "DougW" <post.repl... (AT) invalid (DOT) address> wrote:
tomorrow. I'm pretty sure what I was attaching it to was a new fitting
though (from the retrofit).

Best,
Breton

breton wrote:
Hold on a sec, I boned my description.

..->Evaporator=>accumulator=>compressor-(highside port)->condenser->charge port.
- is skinny pipe, = is fat hose/pipe

They also come like this
http://www.familycar.com/ac1.htm

Since someone upgraded your system I'd take it to a qualified shop to
point out where the correct ports are. Like Spdloader pointed out, you
might have the correct port for the compressor that was installed.
But with a pegged gauge I'd be suspicious.

One thing for certain is you don't want to fill liquid in before
the pump or it will die a horrible death, same as an engine with
water in the pistons.

The other thing is to get the can to fill properly you need to have
the compressor running full tilt. That's done by turning on the AC
full, recirc, and if the pressure is so low it won't kick on then you
need to short the lowside cutoff switch located on the accumulator.
http://revbeergoggles.com/Fixes/sens...essure-low.jpg

FYI for the ZJ
http://revbeergoggles.com/Fixes/sens...ssure-high.jpg

And the fill port is by the overflow bottle.
http://revbeergoggles.com/temp/sensor-coolant.jpg

On my system you fill liquid in that port with the compressor running.

--
DougW

Spdloader wrote:
I boned that description in so many ways it's not even funny. :/

All the vehicles I've ever worked on you filled in the skinny side
and stayed away from the compressor port.

--
DougW

And my instructor told me the can would explode, blowing out one of my
frozen eye balls, that would break into a zillion pieces as it hit the
floor.
God Bless America, Bill O|||||||O
mailto:LWHughes3rd (AT) aol (DOT) com http://www.billhughes.com/


"DougW" <post.replies (AT) invalid (DOT) address> wrote



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