OK, everything is together and seems to be running great. I pulled some plugs today and they look fine. Still new, they need more miles on the to turn brown I guess.

Anyway, this has been going on for some time, even before the mods.

With the AC on the compressor will run for about 3 seconds, then shut off for about 4 seconds, then run for three seconds, then shut off for about 4 seconds.

The idle goes up and down, as it should, when the compressor cycles.

Now, the AC lines get ice cold as they should and the system blows very cold.

So the AC is doing the job it was designed to do, however, is the compressor supposed to cycle like that?

Other than the idle going up and down, there's no problem. It's just a little annoying.

Thanks

That is not normal and will eventually lead to failure of the compressor clutch and possibly the front seal of the compressor. The excessive cycling causes heat build up in the clutch and excessive wear, the heat build up in the clutch can also cause compressor front seal failure. A good first check would be the binary/trinary switch (pressure protection switch). Pull the hsarness off the switch and using a paperclip by-pass it, if the rapid cycling stops then replace the switch, if not keep hunting.

Thanks. I'll give it a shot.

Stupid question, replacing the switch does not require evacuating the system, does it?

no... or, it shouldn't. The sensors have spring loaded ball valves, so when they are removed, no coolant goes bye-bye.

Quote:

First of all, I said it before, FOR THE LOVE OF GOD PLEASE GIVE ME A COOKIE so I don't have to sign in every time!!!!

Anyway, I found 3 cans of R12 in the garage. I'm going to take it to a shop and get the pressure tested. I'll go from there. Should be really cheap/free to have it checked out before I go any further.

Quote:



Matthew

I wouldnt hold your breath on the sensor being sealed, ive never removed one with the system charged (read what the service manual says about it, cause there could be some info there on it)

BUT i do know that when i last had my system filled the guy tried to remove that sensor and gas was pissing out everywhere.

Mine being 94 and factory R134-A could be different respect to something like this, but would be best to check the manual before you go too far into it.

I'm going to take it to someone as AC isn't my thing.

I just wanted to get some information so I don't get ripped off.

I read through the FSM and it is, as usual, clear as mud. I'll re read it later and get help with the big words.

Thanks

You could give this forum a try:

http://www.autoacforum.com/

They were a great resource for me when I had AC problems with mine

A/C guy checking in.

Many GM compressor systems cycle like that, and are intended to do so.

My 96 with auto climate control is one, as well as my 99 Silverado, And an S10 work truck I used to have.

its normal operation, hence the large gap in recommended charge pressures.

My 86 cycles like that when the refrigerant is low. Gotta jump the pressure sensor to override the low pressure clutch disengage.

lower refridgerent is all i know there too

I put in one can, 14OZ, of R12, and it seems to be working fine.

I turned down the AC as low as it would go, then filled it until the clutch just stayed on, there was a drop left in the can so I just put it in.

I don't have a gauge, I think my dad may have one, but the compressor is not rattling so I don't think I over filled it.

I'm going to try to get my hands on a gauge and check it.

A dirty or iced orifice tube (to evaporator) can make that side of the system go high and cycle just like low refrigerant can. when I hear someone having a problem after filling with cans I check this first. FWIW I have personally seen large amounts of water in the small self filling cans, one was almost ALL water! Or after a brownout when low refrigerant was ignored untill compressor locked up then filled and viola dirt in orifice tube. You can jump the high press switch to verify but for extremely short periods. Ever hear a compressor safety valve go off? Over filling a system can cause headaches as well, compressors do not like to pump fluids. last but not least if filling why was it low? and the oil leaks out too, so no oil added can bring the black death to visit your a/c system. Aloha