I am assuming you know that the engine should be running and the A/C
should be turned on. I had a similar problem once, I got some freon in
there but not enough. I put the freon can (or in your case the R134a
can) in a bucket of hot water to keep the pressure up. Also, turning the
ventilation system to recirc and max heat with the A/C on should ensure
that the compressor stays engaged.

Ken W wrote:
>
> I attempted to add a little 134a to my 95 Civic because the low side
> pressure was at the low end of normal. I followed the directions with
> the kit but could not get the system to take any freon. In fact, when
> I gave up, the low side pressure was a little less than when I
> started. Is there a trick to recharging this system?