wrd1972

iTrader: (12)

Yes I know its winter, but spring is around the corner and my AChas gone wierd.

I recently re-cammed my LT1 which requires lifiting the condensor out of the way to make room. I am confident in saying that prior to this, at least during last Fall, the AC worked fine.

Now it kind of half way works. The compressor kicks in and out but there is not much cold air. Also the ACP reading on my Scanmaster hovers around .60 when normally it is above 2.0.

Now the kicker, it has plenty of R134 in it according to my test guage. Also no DTC for low refridgerant. Hmmmm.

What the heck is going on here?

1 FMF

iTrader: (1)

what is an ACP reading?

the ac compressor kicking in and out generally means the system is low on r134a,
there is a pressure switch on the low side I think on or near the accumulator. For any r134a system when pressure drops below around 20psi the switch trips and turns off the compressor. You would be able to observe this with a manifold gauge set with high/low pressure gauges on the system with engine running. only other thing i can think off that would cause the compressor to kick in and out is a bad switch or bad clutch on the compressor actually turning it on & off but that is unlikely. My guess is moving the condensor and probably bumping stuff around increased a small leak.

wrd1972

iTrader: (12)

ACP reading is a parameter that provides a pressure reading to the PCM to make fueling adjustments I assume. It can be viewed on data logging software or in my case, my LT1 Scanmaster.

1 FMF

iTrader: (1)

I would not assume,
if this is a pressure reading from the AC system, such as ACP = AC pressure, the PCM would not use that to make fueling adjustments. The AC system and fuel/ignition system are totally separate.
At most for the AC system there would be a high pressure sensor and a low pressure sensor, and these are just on/off switches that tell the PCM whats happening with the ac system. the low pressure switch will trip around 25 psi, the high pressure switch well over 200 psi. when the high pressure switch trips the PCM will turn on the radiator fans. when the low pressure switch trips, the PCM then overrides any setting on your HVAC head unit in dash and turns off the compressor by disengaging the compressor clutch because the system is low on r134a.

so i have no idea what the ACP reading of 0.2 and 6.0 refer to. I googled it and came across a cadillac page where it said Air Conditioning Programmer

wrd1972

iTrader: (12)

AC is fine. It just does not work when its 20 degrees out. Go figure