R134 conversion on a 1986 Monte Carlo SS; having issues

[86MCSS]

Hi there-

I'm currently in the process of completing an R134 conversion on my 1986 Monte Carlo SS. The conversion kit was purchased complete, and is the entire system- Sanden compressor, evap core, condensor, accumulator, and lines.

I got the kit installed, confirmed that it held vacuum so proceeded with charging.

It took about half a can of R134 (I am guessing now whatever amount displaced the vacuum), and then the compressor started cycling on/off every other second. I jumped the pressure switch which kept the clutch engaged, but still won't draw any more refrigerant.

Any suggestions on what to look for? Kind of stuck.

[86MCSS]

OK, so stupid- the can taps were the issue- screw top had to be set just right to get refrigerant to flow. Got it to take just under 3 cans, and pressure looks mostly correct per the chart.

The kit came with an adjustable pressure switch- what is the procedure for setting these?

[Cusser]

OK, so stupid- the can taps were the issue- screw top had to be set just right to get refrigerant to flow. Got it to take just under 3 cans, and pressure looks mostly correct per the chart.

The current/modern R134a cans have self sealing tops/valves that theoretically reduce loss of R134a. But these are not designed well, and need an adapter or a can tap designed for those. One can apparently use the earlier type of can tap but has to ind the exact "sweet spot" of the adjustment to do that.

I would suggest to buy a can side tap, that's what I have.
https://www.ackits.com/can-tap-3-in-1-1 ... =can%20tap

[JohnHere]

... . I jumped the pressure switch which kept the clutch engaged, but still won't draw any more refrigerant.

If you force-run the compressor, especially with little or no refrigerant in the system, you'll risk ruining it. Your best bet is not to jumper anything.

... . the can taps were the issue- screw top had to be set just right to get refrigerant to flow. Got it to take just under 3 cans, and pressure looks mostly correct per the chart.

Presuming the cans you used were 12 ounces net weight each, that means you've added about 36 ounces of R-134a. The original specs for your car call for 56 ounces net weight of R-12, and 7.0 fluid ounces of mineral oil, which seem to suggest that the newly installed aftermarket system is undercharged. I wouldn't rely on pressure/temperature charts, either. The procedure for charging an original or aftermarket system has been discussed several times on this Forum. What does the supplier say about the correct charge weight?

The kit came with an adjustable pressure switch- what is the procedure for setting these?

I'm presuming that you're asking about the HP/LP safety switch and not a thermostat or electric fan switch. If so, it will come from the manufacturer already set. Normally, a pressure safety switch will cut power to the compressor at about 400 PSI on the high side and about 24 PSI on the low side. What does the supplier say it's set at?