1991 camry ac problems

[rockwind]

mint 91 camry, v6. ac worked fine last year, switched over to 134a. this year, turned on ac, wouldn't work.. hotwired clutch and charged system. don't know pressures but air got cold. then clutch wouldn't workagain. put in more 134a because though pressure switch wasn't kicking on. still diidn't work. put in leak detector, UV stuff. didn't see anything so put in another can of 134a. started hearing weird backfire noises from compressor. looked underneath and can see UV leak detetor all over underneath of exhaust manifold. don't see where it is coming from on hoses or compressor.

the noises are loud and intermittent.

anyone? help appreciated.

[toyomoho]

The system may have too much Freon. Capacity is 1.3-1.7 lbs.

There should be a site glass on top of the receiver. Look into the glass when the compressor starts. Bubbles should form then go away and reappear when it shuts off. If no bubbles, the system is too full or empty.

[rockwind]

well, since i put the leak dye stuff in it, the sight glass is all green, can't see through it. i am starting to think the same thing. do you know what the proper pressure readings are for high and low side?

thanks

[fredk]

your lucky you didnt blow your arm off, ya got too much in it, it is blowing out the relief on the hi side, get someone with gages and be sure the fans are working

[rockwind]

i thought there might be a relief valve, but totally can't see it on the compressor, looked on high side. what's it look like?

i also think i got too much in it, but when i put in one can, air started blowing cool, but clutch still wouldn't run on its own...only if i hotwired it.

what's the deal with the pressure switch?

thanks,

[toyomoho]

Typically it is 21-28 psi on low side, 206-213 psi on the high side. Too much Freon can cause the compressor to lock up.

The compressor most likely has a relief valve but not sure if resets or is a rupture disk.

[rockwind]

i wonder if the pressures change with rpm? i assume those number is for an "at idle" reading? anyone know?

[toyomoho]

1500 Rpm

[fredk]

it does reset, the drier might be plugged up making it cycle and the blow off open up, there is a hi side switch in case too much pressure is on the hi side and one on the low side in case it gets low or starts to freeze up, any one of these switches can go bad and keep the clutch off and inside behind the glove box is a cigarette size black box called an ac amplifier, it goes south the ac clutch will stay off, i have hot wired several yotas with bad amps to make the clutch work but its not easy