My Formula’s air conditioner is not blowing cold air. I have R134a, and the system is fully charged,
yet only moderately cool air comes out of the vents. Any ideas?


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[This message has been edited by 2000RagTop (edited 05-07-2006).]

How do you know the system is fully charged? Is the compressor cycling? If it is then maybe your temp control door is in the wrong position mixing in heat with the cold air.

I think it's more likely that your compressor is not cycling.

quote Originally posted by jscott1: How do you know the system is fully charged? Is the compressor cycling? If it is then maybe your temp control door is in the wrong position mixing in heat with the cold air. I think it's more likely that your compressor is not cycling.

Well I’m assuming that it is charged because when I put the gauge on it, it showed that it was low. then,
I added refrigerant to the system bringing it to full charge

[This message has been edited by 2000RagTop (edited 05-07-2006).]

You may want to check the obvious stuff like the a/c relay, fuses , compressor, & that little resistor thing where the plug is that plugs in to the compressor.

quote Originally posted by 2000RagTop: Well I’m assuming that it is charged because when I put the gauge on it, it showed that it was low. then, I added refrigerant to the system bringing it to full charge

That is a horribly inacurate way to guess at charge level. Unless you are very familiar with air conditioning you will no get a proper charge level. Drain the system and recharge ((80% of R12 xharge is proper on conversions.)

Charge level is critical to have proper cooling, even more so on a conversion.

quote Originally posted by Electrathon: That is a horribly inacurate way to guess at charge level. Unless you are very familiar with air conditioning you will no get a proper charge level.

If you have an otherwise healthy system you could get lucky this way... My GT had been sitting for years, when I bought it, and the owner told me it just needed recharging, (I'm thnking yeah right). But I just plugged in a can or two of R134a refrigerant, (mixed with oil) and believe it or not it blew cold air. It's worked for four years since without me doing anything else to it.

quote Originally posted by jscott1: If you have an otherwise healthy system you could get lucky this way... My GT had been sitting for years, when I bought it, and the owner told me it just needed recharging, (I'm thnking yeah right). But I just plugged in a can or two of R134a refrigerant, (mixed with oil) and believe it or not it blew cold air. It's worked for four years since without me doing anything else to it.

I’m hoping this is the same type of situation with mine….
The previous owner had the system changed over to R134a, and he said it work fine.
The car did sit with not much driving for almost 6 years. When I got the car, he told me that
the system would probably need recharging. So…..I picked up a couple of cans of ‘recharge”
And added it to the system……”I’m just not getting any cold air”

An A/C system needs to be within about 1/4 pound of correct to cool good, within about an 1/8th pound to cool at it's best. A Fiero holds 2.5 lbs of R12, so converted it will hold 2 lbs of 134A. Being within a "pound or two" on a two pound system is a very wide range. Also, you should only add oil when oil has leaked out, not just because. An overcharge of oil will make the system not function properly too, as it takes up space in the system, simulating an overcharge of refrigerant.

If the compressor is working and if you added 2 pounds of 134A my first guess is that you have a gross overcharge in the system. More data would help a lot in the diagnosis. You said it was low, but do not say how you determined that (it can be difficult to tell.) Was the engine running or not when you took a reading? What was the high side preasure? What was the low side preasure? What year and model of car? Some Fieros use a cycling clutch and come use a variable compressor.

quote Originally posted by Electrathon: An A/C system needs to be within about 1/4 pound of correct to cool good, within about an 1/8th pound to cool at it's best. A Fiero holds 2.5 lbs of R12, so converted it will hold 2 lbs of 134A. Being within a "pound or two" on a two pound system is a very wide range. Also, you should only add oil when oil has leaked out, not just because. An overcharge of oil will make the system not function properly too, as it takes up space in the system, simulating an overcharge of refrigerant. If the compressor is working and if you added 2 pounds of 134A my first guess is that you have a gross overcharge in the system. More data would help a lot in the diagnosis. You said it was low, but do not say how you determined that (it can be difficult to tell.) Was the engine running or not when you took a reading? What was the high side preasure? What was the low side preasure? What year and model of car? Some Fieros use a cycling clutch and come use a variable compressor.

When I checked the system. The engine was running, warmed up, and the air conditioner was set on high.
Also, 88 Formula. lol

I’m using the gauge that came with the recharge can, I also have a hand held tester for checking.
When I first checked the system, I had a reading of under 25 (in the blue) which the can says is low.
After adding refrigerant, the reading is now at about 40, which is marked “filled” on the gauge.
At 45, the gauge says “alert”

I didn’t add 2 lbs to the system?? I would estimate that I added approximately, 6-8 ozs out of the 22 oz can

There doesn’t seem to be any leaks (at least no oil on the fittings)

[This message has been edited by 2000RagTop (edited 05-07-2006).]

quote Originally posted by 2000RagTop: I’m using the gauge that came with the recharge can, I also have a hand held tester for checking. When I first checked the system, I had a reading of under 25 (in the blue) which the can says is low. After adding refrigerant, the reading is now at about 40, which is marked “filled” on the gauge. At 45, the gauge says “alert” There doesn’t seem to be any leaks (at least no oil on the fittings)

Was the system running? Or off? You really can't tell much by just looking at the low side. The cycle switch (if it has that system, I just realized you have an 88, but do not have an 88 manual. I think 4 cyl use a V5 and a 6 cyl uses a DA6, but really guessing) should be adjusted to go on and off at 24 and 44 lbs. If it was not properly readjusted durring the conversion it will cycle at 26 and 46. Temperature will also affect the readings, as preasure is related to temperature.

quote Originally posted by Electrathon: Was the system running? Or off? , but do not have an 88 manual.

Running.

Yes, I have a 88 shop manual ?? Is there info on this in there? lol "I guess I'll look" F

I'm no expert on a/c but with engine running and a/c engaged on high pop your hood "the front one" and look for 2 metal lines going into something called an evaporator. One line is bigger than the other. The big one should be cold and sweating & the smaller one should be "HOT".

If this is the case then your problem is inside at the controls or stuck flapper in the ducts, etc.

Somebody else can chime in if this is in error but this is my 2 cents.

If the compressor seems to be pumping, try draining the system and filling with 2 cans of 134A (without oil.) It would be a good time to verify that the oriface was switched from a standard oriface and install a variable oriface (VOV.) Also if the previous person did not replace the acumularor, now is the time to do it. The origional desicant is not compatable with 134A, so it should always be replaced durring the conversion. One thing that you can actually do with the guage that came with the guage they gave you is to adjust the preasure cycle switch (if you have one.) It should be adjusted down 2 pounds so it cyclea off at 24 and on at 44 pounds.

Air conditioning scares the crap out of me, it seems like a black art to me. But when you have a leaky system it's darn near impossible to keep it at the proper level of charge. On my other car, If the car sits for a month or more I get no cold air. I hit it with a can of R134a and it gets cold again for another month or so. I figure $10 a month is cheaper than finding the leak.

Johnathon,

While it would definatly be best to just fix the leaks, I do agree that sometimes you can get away with what you are doing. The biggest advice I would have for you is to never add 134A/oil mix to the system. You will soon have such a major overfill of oil that you will have to do a flush to get it back to normal.

I ran outside and after a quick observation shows me that the clutch isn’t moving while the air is turned on.
And I’m not getting the “cold feel” in the front of the car under the hood……..

[This message has been edited by 2000RagTop (edited 05-08-2006).]

If your hunting down leaks --wouldn`t it be easier --to shoot a dye pack in there ?

quote Originally posted by 2000RagTop: I ran outside and after a quick observation shows me that the clutch isn’t moving while the air is turned on. And I’m not getting the “cold feel” in the front of the car under the hood……..

Something is either electrically inop or is you have a leak and the preasure switch is keeping the system off.