truckdoug

iTrader: (25)

I originally posted this in conversions, but I thought I'd cross post it here to get more eyes on the solution.

Backstory: I'm going to run a stand alone a/c system original to my swap vehicle ('79 c10) and I think I have the nuts and guts figured out.


There is one bit I'd like to sort out though. I would like to trigger an increased engine load and have the PCM bump idle airflow when the compressor is engaged.

I am unsure of how to go about doing that.

I think I can simply trigger the presser sensor circuit by spoofing the signal with a resistor ( off, the signal will be 0v, on will be 2.5v) and that should kick on Fan #2. In the tune itself I can bump the airflow when fan 2 comes on.

I may need to disable some DTC's but I think my reasoning is sound. The PCM does a couple logic checks when you request a/c....like is the pressure sensor maxed? is the clutch compressor okay? and all that stuff can be toggled in the DTC's

If I'm missing an easier way to bump engine airflow, let me know (this is intended to work with a p01 computer only)

Thanks gents!

G Atsma

Wouldn't the ECM keep the idle compensated when the A/C comes on? That's the actual goal, right?

JoeNova

The PCM just uses a simple signal to tell when the compressor is turned on. You can wire pretty much any A/C system up this way.
Example (unfortunately I'm at work and this isn't the one I have made up at home):