I just purchased the Holley HP system and I have questions related to what I need to use the 4 I/O pin outs for. One I know will go for TCC but I need a relay I believe, any suggestions on a good relay to choose?

Another one or two will go to the fans as I have a dual fan setup. I could wire them in series to only use one output I guess but I like the dual fan functionality

The 4th is really the big question. I see something in the holley EFI program for A/C control but I am not sure what the factory ECM accounts for regarding the A/C. What is the ECM controlling?

What about evap canister? I know the '730 ECM triggered this before. Can I just leave this hooked up but not functioning? Should I be using one of the I/O's to trigger this as well? Thinking maybe best to delete it and just get a vented cap but not sure what other people have done.

All that have done this swap or to a similar aftermarket system your input is much appreciated.

 

Since no-one has answered yet I'll give a couple a go. Any sturdy, heat resistant, automotive relay will work for the TCC lock-up.

Quite a few cars turn the air-con off when you got to full throttle just for that little bit extra. I think that's about it really.

 

Can I damage the A/C compressor if I don't hook this up? The Holley efi software has provision for control, but with only 4 I/O ports I am wondering if this is a good use for one or just say screw it. So does the ecm switch the control relay to a different ground or what?

I found a pico relay kit that works for tcc so just trying to lock down last port

 

I don't think you will damage the A/C if you don't hook it up, it's just for a few extra HP at full throttle. Usually in auto applications a relay has 12v on one of the low power terminals and is activated by grounding the other.

 

Some day i will get my holley hp out of its box and hooked up.

 

The AC hookup is to raise idle during clutch engagement

you have 8 ports to use with the HP unit 4 power control and 4 ground control the powers will send the 12v signal in or out and the 4 ground will send a -12v or complete the ground

any relay will be good too

 

Ive got a HP unit that I have installed on a monte carlo and a dominator thats going on my camaro

 

So if my car is an Auto, the A/C control is not used?

 

it is because it will bump your idle up a couple hundred rpm when the AC is on it should just be a feed that reads off the clutch engage or the ac on switch

 

Correct...A/C is an input for idle speed bump sensed when clutch is engaged. HP ECUs have only 4 outputs, 2 +12V triggers, 2 ground triggers max of 2A or a relay is required. The other 4 channels are inputs.