Strange AC Trouble?

[Redline]

Well my A/C wasn't working, so a friend of mine that works in the auto shop at school hooked it up to the gauges for me for free and tested it. He said that my freon was fine and had plenty of pressure, but that right after the ac was turned on the pressure would get really really high in the system.
My radiator fan wasn't working and he thought that might be the problem but I have fixed that and still no AC. He is going to look at it again for me, but I thought I would check with you guys and see if anyone has had this problem or knows what it might be. Thanks. :wave:

 

[HopefulSHO]

Try to observe the clutch on the A/C compressor when you turn A/C on. It should be spinning (or cycling on and off) with the pulley.

 

[JTSHO]

if youre hooked to the low side near the fire wall, and the pressure still was high, i would check your cycle switch on the accumulator it shuts the compressor off when pressure gets above i believe 45. also make sure your condensor is clean too...

 

[Lupo]

Try replacing the line between your condenser and evaporator core. This houses an orifice "Evaporator core orifice" and screen. This part can sometimes get clogged and can produced the problems you are describing, especially overpressure problems. This line runs under the battery (the actual orifice part is 1/2" and directly under the battery) and to the back firewall.
You can remove this line, and clean out the orifice with a compresser or something, but because the replacement line is only 35$ or so, I'd just get a new one.

 

[Redline]

Ok, my buddy and I are gonna check it out again on tuesday so I'll see what we find.

 

[SHO_Diehard]

If you take the line out or replace it, make sure it's against the firewall and away from the power steering pulley when you install it. The pulley can cut a hole in the line, ask me how I know that...

 

[Redline]

Well the shop looked at it again but they said that my compressor wasn't turning on at all. This is really strange because it was the first time they looked at it. As I understand it there is a switch somewhere that can be jumpered to verify whether or not the compressor still works so I'm going to try to find that and see what happens.

 

[rangerj]

If the compressor is not being turned then the clutch is not being engaged. Check the clutch gap for .025 to .035. If the gap is too large the clutch will not engage. If the gap is OK then jump the low pressure switch connector to see if it will activate the clutch. If not, check the clutch coil. It should become a strong electromagnet when battery voltage is put through it.

If battery voltage will not activate the coil it needs to be replaced. Replace the clutch and coil as a unit if the coil needs to be replaced. Gap it correctly before installing it and follow the manufacturers instructions on burnishing the clutch surfaces (wearing in the clutch).

Note: the clutch and coil can be replaced without removing any of the A/C lines. You may have to loosen and free the compressor to make it easier to change the clutch coil, face, and pulley. The snap rings that hold the coil to the compressor, and the pulley to the compressor are "bevelled" and the bevelled side should face outward, ie towards you, when they are installed correctly.

 

[Redline]

Wow, thanks for the info rangerj! Looks like I have all my troubleshooting work cut out for me. Now I just need to find time to do it! One question though, how do I check the clutch gap?

 

[rangerj]

Feeler gauge! The gap is between the clutch surfaces; 1. on the front of the pulley, and 2. the clutch face.

 

[TYSHO]

Would the clutch not engaging cause the high pressure?


I just made some runs with the 92, actually another member, and now my a/c is shot. It's dark and I did not hear the compressor kick on. The pressure was high though.

IIRC, you can bang the clutch with a pipe or something, to help it engage, considering the switch on the accumulator is good, right?

I need to fix this asap, in the morning...it's hot!!!

 

[Lupo]

If your compressor is not working, this would not cause a high pressure situation. When the compresor is off, it simply equalizes pressure between high and low side.
High pressure occurs when the compressor is running, and the evaporator core orrifice is clogged or blocked, creating too much pressure on the high side.