Question concerns an aftermarket AC in street rod powered by computerized LT1. AC is not yet operational so I cannot test.

As a general statement on cars I've owned before when AC is turned on at idle it generally slows down the idle sometimes killing the engine with the drag from the compressor unless there is an "idle up" solenoid. This is my first fuel injected, computer controlled hot rod with AC so kind of new territory for me

On the fuel injected 94 LT1 engine in my car is that potential drop in idle speed offset by the IAC only or is it necessary to have factory AC pressure and temp sensors plugged into the PCM for the IAC to make idle speed adjustments?

It looks like a major PITA to hook up factory evaporator temp sensor and factory refrigerant pressure sensors between the vintage air controls and the pcm.

Ideally I would like to run the AC independent of the PCM including an aftermarket trinary safety switch. Anyone see any problem doing this re. the idle speed or other variables? Thanks for any help.
Jerry

 

The PCM does have an IAC offset for a/c anticipate vs. pressure table. However, regardless of whether it sees the pressure from the sensor on the a/c pipe, the PCM is going to try to hold the idle at the prescribed programmed RPM.

 

Thanks for the reply. I am slowly working my way through the AC hookup utilizing the PCM and AC sensors. Since I have a spal fan and controller it is a little more complicated. Vintage Air is very little help on this one where a FI car with PCM is involved. One gets the impression they are more comfortable with carburetors and bypassing any PCM or PCM sensors.
Jerry