Taurus Car Club of America : Ford Taurus Forum banner
1 - 20 of 20 Posts

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #1 ·
First off...

YAY!!! MY A/C WORKS AGAIN!!!! :thumb:
Ok, now here's the latest episode in the ongoing saga of my A/C system...

I replaced my A/C compressor last month sometime since the pulley bearing on the last one decided to throw it's grease and seize up on me. :angryfire: So today, I pulled a vacuum for an hour, verified that it maintained the vacuum, and recharged the system with R-134a (conversion kit and new refridgerant), including the appropriate oil charge. And it blows colder than a mother!! :banana:

Only thing is...

At idle, the compressor runs normally. However, at anything above idle, like 2200RPM and higher, the A/C clutch cycles. Few seconds on, few seconds off. I don't like the idea of the clutch cycling on and off at 3500RPM, and so my question is this...

Is this normal? :blink: If not, anyone have any recommendations as to how to make it stop doing that. Like make it run all the time (I know some wiseass is gomma recommend that I don't turn it on at all :p)

Thanks in advance fellas. And ladies, if any of you decide to reply. B)

~Hamal

P.S. I'm sure that there are some typos in here. But I just had a 22oz. of Heineken. Deal with it...
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #3 ·
Originally posted by rudedog@Jun 10 2004, 12:05 AM
What were your gauge readings, how many cans of refrig did you use?
What was the ambient temp outside?
What was the vent temp. when you were done?
Compressor on, 250PSI at idle on the high side. 35PSI at idle on the low side. Higher engine speeds yielded higher pressures.

Ambient was in the 90's with high humidity.

Vent temperature was really friggin cold. :D (I didn't measure it with a thermometer)
 

·
Registered
Joined
·
411 Posts
Racer X,

The conversion kit, it it contain PAG or POE (Ester Oil)? What was the manafacturer of the compressor?

The pressures seem a little high (low side)

How much R-134a did you use, remember, it should only be maximum of 80-85% of the original R-12 charge.

And yes, it is supposed to cycle on and off, that is it's job.
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #5 ·
Checked again today:

225 PSI High side.
30 PSI Low side.

Cycling rate increases as the engine speed increases.

Is that still normal? :unsure:
 

·
Registered
Joined
·
411 Posts
The cycle rate usually will increase at higher RPM's. This is also when it will cool better.

Those numbers look a little better than before.

And the sides will always work opposite of each other. In other words, the low side should decrease and the high side should increase. If this is not happening, then you have trouble.
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #7 ·
Bump.

The cycling rate is like 1-5 sec on 5 sec off above 3000RPM ( ~80MPH). That's normal? I haven't had A/C since forever, but those cycle rates can't be right. My mom's Jeep (yes I know, Chrysler != Ford) doesn't cycle on and off like that.
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #8 ·
Questions I forgot to answer:

Roddog, I didn't use cans. I used a Snap On A/C machine to service the system. It's an R-12 system that I converted to R-134a. At an 85% conversion, the charge was 1.915lb, or 1lb 15oz (I rounded up from 14.6oz). This was after a 60 minute vacuum pull.

JJ, I used Ester oil, not paginated oil.
 

·
Premium Member
Joined
·
14,127 Posts
Is the clutch on the compressor new? Did you change the low pressure switch?
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #10 ·
Originally posted by SHOZ123+Jun 12 2004, 10:12 AM--><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (SHOZ123 @ Jun 12 2004, 10:12 AM)</td></tr><tr><td id='QUOTE'>Is the clutch on the compressor new?[/b]

No. The compressor came out of a 1993 ATX with 120,000 miles on it (dead transmission).

<!--QuoteBegin-SHOZ123
@Jun 12 2004, 10:12 AM
Did you change the low pressure switch?[/quote]
No, but I was thinking I should do that and see what happens. I'll pick one up on my next day off (Friday. <_< )
 

·
Registered
Joined
·
411 Posts
Good, the machines are much nicer than those damn cans.

The only other thing that I could think of is the clutch cycling switch needs to be adjusted for R-134a, it needs to cycle off at a lower pressure.

And BTW.... Chrysler systems are TXV, and GM and Ford use CCOT systems, totally different.
 

·
Registered
Joined
·
222 Posts
I would see If ford has a service bulletin on how to convert this car to R-134a and compare what the difference is between the service bulletin and what was done. Maybe there is a new metering device or PSI switch that should have ben replaced with the conversion.
Maybe one of our members has access to ford service bulletins and would like to share. :)

Happy Berthday Racer X B)
 

·
Premium Member
Joined
·
14,127 Posts
If the R12 and R134A run at different pressures then you should probably need a R134A low pressure switch. Easy to see if it is the culprit. Just jumper it and take a drive.
 
G

·
Originally posted by SHOZ123@Jun 13 2004, 12:24 AM
If the R12 and R134A run at different pressures then you should probably need a R134A low pressure switch. Easy to see if it is the culprit. Just jumper it and take a drive.
Excellent info here!

So, for the proper low pressure switch, I could use one off a 94 and up car, since they came with R134?

Hamal, sorry about not calling back. I just got the message Saturday morning. Stupid AT&T wireless.....
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #15 ·
Originally posted by SHOZ123@Jun 13 2004, 01:24 AM
If the R12 and R134A run at different pressures then you should probably need a R134A low pressure switch. Easy to see if it is the culprit. Just jumper it and take a drive.
I didn't think they did, since I had to lessen the total charge by 15%, but it's worth a shot.
 

·
Premium Member
Joined
·
14,127 Posts
The '92 pressure switch opens at 24.5 psi, the '97 pressure switch opens at 22-28psi. So I doubt this is the problem.


A7 CHECK COMPRESSOR CLUTCH


l Use refrigerant system pressure/clutch cycle rate and timing evaluation charts.

l After preparing vehicle as follows:

-- Hook up manifold gauge set.

-- Set function control at MAX A/C.

-- Set blower switch on HIGH.

-- Set temperature lever full COLD.

-- Close doors and windows.

-- Use a thermometer to check temperature at center discharge register, record outside temperature.

-- Run engine at approximately 1500 rpm with compressor clutch engaged.

-- Stabilize with above conditions for 10-15 minutes.

l Check compressor clutch off/on time with watch. Refer to charts for normal clutch cycle timing rates.

Compressor cycles very rapidly (5 seconds on) (5 seconds off)
GO to «A8».

PINPOINT TEST A: INSUFFICIENT OR NO A/C COOLING--FIXED ORIFICE TUBE CYCLING CLUTCH SYSTEM


A8 CHECK CLUTCH CYCLING PRESSURE SWITCH


l Bypass clutch cycling pressure switch with jumper wire. Compressor on continuously.

l Hand feel evaporator inlet and outlet tubes.

Outlet tube same temperature approximately -2°C-4°C (28°F-40°F) or slightly colder than inlet tube (after fixed orifice)
REPLACE clutch cycling pressure switch. Do not discharge system. Switch fitting has Schrader Valve.
 

·
Registered
Joined
·
222 Posts
the PT chart shows R12 two degrees colder then R134a at 30 psi there for the cutout point for R134a should be approx two psi less then R12

R12 at 24.5 psi is 25 degrees
R134a at 22 psi is 25 degrees
 

·
Registered
Joined
·
411 Posts
Those numbers are exactly right. And yes bob, a 1994 or newer switch will work.

Or, there are adjustable aftermarket switches.

Racer X, R-134a operates at higher pressures, hence less charge.

You did replace the Accumulator and O-tube right?

Oh yea, the compressor you used, is it an FS-10 or FX-15? 1993 was the transition year. The FS-10 is the HD version for R-134a, the FX-15 works, but is not recommended.
 

·
Premium Member
Joined
·
5,111 Posts
Discussion Starter · #19 ·
Originally posted by JJ57@Jun 14 2004, 03:05 AM
You did replace the Accumulator and O-tube right?
:unsure:

Yeah, um...

I did pull a vacuum on the system after I swapped in the new (ie. working) compressor, but I didn't charge it because of the lack of refrigerant and gauges, so the atmosphere exposure was minimized. That, and the price quotes I got for those parts were retarded! :blink:

All SHO's from 1989 to 1999 used the 10P15F Nippondenso A/C Compressor, which had none of the shortcomings of the FS-10 and FX-15 compressors, and can handle the added load of the R-134a pressures with little to no ill effects.
 

·
Registered
Joined
·
411 Posts
I totally forgot it was an SHO, yea, your ok in that department.

About the accumulator and O-tube, the o- tube you can get away with, however, the accumlator, you can't.

The Dessicant inside is not really recommended for R-134a, and you should ALWAYS change this piece when dealing with R-134a because of the sensitive nature of it and the oils.

You may want to look into this.
 
1 - 20 of 20 Posts
Top