A/C shuts off at 1.34 TPS...

[jsta6]

My TPS settings are:

.40 - 4.2 at idle

4.7 - 4.8 at WOT

A/C is not supposed to shut off until 4.0, right?

Mine shuts off while cruising at 1.34. But when it does, DirectScan says A/C is still on.

WTF?

I believe the DirectScan is correct, becuase it says the A/C is off when I manually turn it off using the A/C switch / slider.

 

[scottyb]

It's more likely that a pressure switch is cycling the compressor. Mine cycles on morning startup because of the initial high idle and the cooler conditions. I hooked manifold gauges up last weekend and noted that the low side will cycle off the compressor when the pressure drops below 20lbs. (I'm sure there are other conditions that cause this, but low pressure was the only one on mine) Higher RPM results in lower pressure on the low side. I did not add freon, but released a fair amount just from putting the gauges on and off. After that day, my compressor had cycled off whenever I rev the motor for the same reason due to low freon. I added some last night and all is well so far.

Does it blow cold on a hot day?

 

[jsta6]

Thanks.

Yes, it blows cold on hot days.

Someone else mentioned that it was a pressure switch.

Thanks again.

 

[Black Car]

Years ago I was told that the AC when on normal would cycle on/off as normal operation, but when on MAX AC the compressor wouldn't cycle. Don't know if true or not.

Gary

 

[Alkyholic]

I agree with scottyb


naw the difference between max air and normal is that max air "recools" the air that is already in your car. Normal brings in fresh air from the outside and cools it then blows it into your car. I am in an AC class for college and we are going through troubleshooting crap. If you are low on r-12/r134a, it will cycle the pressure switch untill there is enough heat to raise the pressure of the refrigerent.

Andy

 

[ijames]

The tps for a/c off is just one more thing a chipmaker can set, so you'll have to ask yours for the exact answer. As critical as the engine heat load is on these motors, I don't think a tps of 1.34 is horribly low anyway - that's probably just starting to make boost on some cars. I forget exactly where I set it on chips I make for people, but it's between 1.5 and 2 I'm pretty sure.

Oh, if you want to minimize the engine temp with a/c on, use the max setting to get recirculation so you won't have to cool and dry all the incoming air all the time, and set the fan speed as low as possible. Using max vs norm is worth a few degrees, and I know that on a 90+ day using the lowest fan speed vs the highest, while on max, is worth at least 10 degrees of engine temperature on my car.