well what do you know....problem duplicated....lol....my compressor will run continuously at idle....as soon as I start driving, it cycles on and off....I took it and had it professionally vacuumed and recharged....still does it....I have been doing some research and read where some one had this issue and found that while filling the system at idle resulted in good high and low side readings, at higher RPM's, the low side would drop below 20 PSI which was enough to trip the low pressure switch. Their solution was to add more refrigerant at a higher than idle RPM. I'm going to try that tomorrow. If that don't work, I'm going to install DPST switch and run constant 12 volts to the compressor when I need it to stay on, then run normally in the other position. Kinda like a "auto/manual" switch for the compressor clutch.

 

thats a bad idea, the compressor needs to turn off. it can build too much pressure and blow a line or something worse. i saw a compressor at this radiator store here, the whole side was blown out from running a constant 12V.

 

Thats what I was wondering and wanted to hear. I just gotta figure out whats causing it to kick off. The PCM controls the compressor and there are only 2 inputs from the AC system to the PCM, low pressure switch and evaporator temp. (or condenser temp, can't remember).

 

Interesting...................I replaced this little switch on top of the box because it was cheap and easy. It didn't work and I have no idea what it was. As you all know, I know nothing about air.

We will keep fiddling and we will figure this out

 

Wait a second. Why did your car leave their shop, and you paid them (I'm assuming), when the problem isn't fixed? What was their diagnosis of the problem? And did you tell them what it's been doing to you so they could road test it under the same conditions? Seems to me it should have been easy for the professionals to figure out what's going on since they should have the right test equipment.

 

If the compressor is on at idle and goes off when you drive, then maybe you have over charged the system. The R134 systems also have a high pressure switch, which shuts off the compressor (Which is why a direct connect 12V wire is a bad idea) if the pressure is too high. The faster you run your engine, the faster the compressor goes, so high RMP shutoff could mean too much R134.

The best way is to have a shop with the proper equipment add the coolant and oil based on weight. If you are doing it yourself, you should do a google search for ambient temperature R134 chart.

 

Yep, I'm taking it back to them. It was a long story, but when they went to check it out, the high side schrader valve blew off and they just replaced that, recharged and said I was good. I'm going to be going back and let them road test it with me so they can see what it is doing before I start doing all that other crap I was talking about. At least now I know it has been properly vacuumed and charged

The wiring diagram does not show a high pressure switch, only low pressure and evaporator temp. I've had a gauge on the low side and it never goes over 45 PSI with the compressor running at high (2k) RPM's.

 

Took it back today. They were able to find that at higher RPM's, it WAS tripping out on high pressure. The compressor itself has its own pressure switch to prevent self destruction apparently. Anyway, the problem is either a partially condensor or expansion valve. I'm going to order a new condenser and expansion valve and we shall see what happens.

 

do them yourself and save some money, its really easy. you also want to replace the dryer (the aluminum can next to the left strut tower) it keeps moisture out of the condenser.

 

oh yeah, I'll do everything myself. I only pay labor for things I'm not quite sure of (like automatic transmissions). I replaced the drier and expansion valve when I put it all back together the first time. I suppose I could replace it again. Like the guy at the shop was telling me, I don't know why the AC delete was done on this car, it could have been because the original compressor self destructed and the previous owner did not want to go the expense of replacing it, so the system could have had all sorts of crap in it now that crap is flowing around clogging up things. Just orderd a new condenser and expansion valve off rock auto.