I had my car converted to 134a about 7 or 8 years ago and this summer I've noticed that the compressor seems to be short cycling (10 second bursts or so) and I wanted to try topping it off before assuming that it was anything more serious. As I always do, I came here to make sure it was a straight forward process, and then went out and picked up a can of coolant.
Now, this is where my confusion comes in. According to the pictorials here most people have a low side quick connect port with a blue cap on it that is used for filling the the canister. Mine, however, has some big ol' electrical plug put in there. What gives? Where would I hook up a recharge on this beast?
that is the pressure switch that makes it cycle. you CAN just unscrew it (you will lose no Freon), screw on the 134 adapter, put in a can of 134, then remove the adapter and put the switch back on. although, there should BE 2 ports on that line, 1 for the switch and 1 for the 134 adapter. Look at the "LINE"
I bet there's another port that's hidden behind one of the metal lines.
The correct accumulator has two shrader valves - the one that you show with the sensor installed, and then another one on the other side, where the sensor SHOULD go. My guess is that the sensor was installed on the wrong port. But no worry - the sensor simply unscrews from the accumulator and you don't even have to drain the refrigerant to do so.
You fella that answered his question, seem to know about the Fiero A/C system, so I'm going to ask you another question. Is it normal for the pump to switch on and off fairly often, like every 5-10 seconds? And...is the Fiero pump typically noisy when it's running? My system cools just fine, it just seems those things are odd...the noise and the switching!
You're awesome, as always! Sure enough there was another hookup on the backside, fitted with a r134a adaptor and blue cap. On top of that luck - I was able to get the hose on it and had it filled up in a jiff!
@Hypo327 - mine was short cycling, similar to yours. Putting a bit of a refill in it seemed to have solved that problem, at least for the time being. I'm sure these fine gents can probably give you some other/better tips than me.
You fella that answered his question, seem to know about the Fiero A/C system, so I'm going to ask you another question. Is it normal for the pump to switch on and off fairly often, like every 5-10 seconds?
No, not normal. 'Short cycling' as described. Typically caused by leaks. Put some AC dye in the system, and tighten the low and high side schrader valves, this will help pinpoint any leak. Could also be the pressure switch not being adjusted properly for R-134A. It should kick off at 21 psi on the low side. Check low and high side pressures with a gauge set, car on and off, and note the outside temperature at the time. This will tell you what the system is doing.
And...is the Fiero pump typically noisy when it's running?
My system cools just fine, it just seems those things are odd...the noise and the switching!
Vent temps should be below 50 F, even on a hot day. As low as 35-40 if you're lucky.
Looks like whoever worked on your car put the cycle switch where the fill port goes, and vice versa.
Is that a problem? The only reason I ask cause the accumulator I have has the two ports opposite each other. If I put the switch where it normally goes it won't fit but if I can swap them then i might be able to make it work. Otherwise a new accumulator is needed.