lilrobo

dont know if this is the right spot ...

i have a 5.3 and a 4L60e in my 55 chevy , i am adding a/c ( VA gen IV ) to it ,
i have a elect fan that my programmer set to come on, i dont have any wires coming from my computer ( ill have to add one if needed ) what i need to know is should i have my a/c come on as soon as my a/c is on ? and do i need to have my engine idle bump up a little ?? or what do i need to do if anything ??

thanks guys , if not the right spot redirect me please

proper

You can have your fan run constant when your A/C is turned on and it will keep your high pressure from spiking.Some systems have the pressure swith on the high side controll when the fan comes on but the pressure can be as high as 225 to some times 275 PSI.With the fan running all the time, your high side shouldn't get over 165 if the system has the proper amount of R-134a.You really don't need to go through the computer to have the A/C work,but the wiring instructions that come with the Vintage Air system will walk you through that part.

lilrobo

right now my fan comes on about 205 and stays on ,i have never seen the temp higher than 208 , 209 ,, something like that ,the instruction dosnt ssay anything about going to puter ,

thanks

turbo_bu

VA doesn't understand how to work with a PCM. There stuff is basically a stand alone system. I'm currently doing a swap with a VA kit, and basically, I am going to piggy back on it to allow the electric fans to control based off of pressure, temp and vehicle speed (just like GM designed it). It will all depend on how much you want to mess with it to get it to function. I am adding in the GM pressure sensor. You don't have to. As was mentioned, you could just signal your fans to turn on when the A/C is on.

lilrobo

that being said if i do as it is , by the wiring that comes with VA , the fan will come on as normal , and the ecm will bump up the idle if needed ??i do have a binary switch tha came with the kit

thanks

turbo_bu

You will need to tell the PCM that the A/C is on. This is what I meant by piggy backing on the VA setup. There are inputs to the PCM that tell it that the A/C is on (C2 pin 18). I am not sure if you just hook this one up, if it will work as intended, or if you will also have to hook up the request (C2 Pin 17) and A/C clutch (C2 pin 43)wires too. The fans will be kicked on only if you also install the A/C pressure sensor. This assumes you are running an F-body OS. If your running a truck OS, then the wiring is a little different.

G-Body

iTrader: (4)

What year/make/model is your PCM flashed as? If its a red/blue PCM it should be easy to get hooked up. If its green/blue it might be a bit more difficult.

If your motor is stock you don`t really need it to bump the idle up.....now if you have a big cam then you probably do. Either way you want to make sure your fans get triggered when the A/C is on.

hookemdevils22

iTrader: (12)

The usual way an electric fan is controlled is through a ground signal, whether via the PCM or temp switch. The simplest way to connect the VA kit is by using their trinary switch, (which they hopefully included with your order) - it supplies a ground signal when the AC is selected. Run the wire from the trinary switch to fan relay terminal 86 or 87, whichever is the PCM/switch-controlled ground.

I wouldn't bother with the AC request signal - the engine should be fine without the bump in idle.

garys 68

iTrader: (1)

I'm running 2 aftermarket AC systems without ECU AC request, no idle increase. No issues.
Consider a dual fan set up. One on temp the other on temp and/or trinary switch. It's worked well for me. VA has the trinary switch and wiring diagram on their website.

lilrobo

thanks gary , i been looking into that