Figuring out ISIS and LS2

[Chris 68]

So heres the deal, I ordered my isis 3 cell kit and i have an LS2 with the harness already modified by wait4me. I'm trying to figure out my inputs and outputs for everything with isis. I've spoken to Jay with ISIS and i need to find out a few more things about the LS2 computer. Does anybody know what outputs (fans, fuel pump, etc) go to ground as you cant use the 12 volts for the isis inputs. Also how the hell do i wire everything together? I'm a little lost as what i need the computer to do, what i need to wire to get it started ect. Also for my constant power (CD/ Windows and so on) how do i wire those off the same output even though they draw different amps? Basically i dont know crap about electric in cars but i can learn quite easily

[Mkelcy]

So heres the deal, I ordered my isis 3 cell kit and i have an LS2 with the harness already modified by wait4me. I'm trying to figure out my inputs and outputs for everything with isis. I've spoken to Jay with ISIS and i need to find out a few more things about the LS2 computer. Does anybody know what outputs (fans, fuel pump, etc) go to ground as you cant use the 12 volts for the isis inputs. Also how the hell do i wire everything together? I'm a little lost as what i need the computer to do, what i need to wire to get it started ect. Also for my constant power (CD/ Windows and so on) how do i wire those off the same output even though they draw different amps? Basically i dont know crap about electric in cars but i can learn quite easily

The simplest thing to do would be to treat the LS2 ECU and harness as a single device powered from the ISIS power cell, and let it control your fans, fuel pump, etc. as if you didn't have the ISIS system at all. That is, let ISIS send power to the ECU and harness, but let the ECU and harness control everything they're capable of controlling. You'll need some relays to power up the fans and fuel pump, but the relays would be triggered by the LS2 ECU and harness, not ISIS. The relays will need to get their power directly from the battery, through appropriately fused connections.

I don't think I'd do anything with constant power (i.e. on all the time). Instead, I'd power things like the radio, power seats, power windows in the ISIS ignition mode and then have the accessory position on the ignition switch (or a separate switch) going to ground when you wanted to power those things without the car running. You may need some additional ISIS mapping to get the accessories working.

[Chris 68]

The simplest thing to do would be to treat the LS2 ECU and harness as a single device powered from the ISIS power cell, and let it control your fans, fuel pump, etc. as if you didn't have the ISIS system at all. That is, let ISIS send power to the ECU and harness, but let the ECU and harness control everything they're capable of controlling. You'll need some relays to power up the fans and fuel pump, but the relays would be triggered by the LS2 ECU and harness, not ISIS. The relays will need to get their power directly from the battery, through appropriately fused connections.

I don't think I'd do anything with constant power (i.e. on all the time). Instead, I'd power things like the radio, power seats, power windows in the ISIS ignition mode and then have the accessory position on the ignition switch (or a separate switch) going to ground when you wanted to power those things without the car running. You may need some additional ISIS mapping to get the accessories working.

Well my only thing is, i'd like the fans to be contorlled by isis so i can have them on by the computer, vintage air and myslef via key fob or delayed after the car is turned off. When i talked to jay, he said the outputs from the ls2 computer for the fans are to ground so i can hook those up to the mastercell, the fuel pump i can hook up to a relay since its 12 volts and use the otherline off the relay to the master cell. But what do i do for everything else? Like the keyed inputs off the ls2 computer (12v keyed for example) Also how would i go about wih the vintage air so that when the a/c is on, the master cell will turn on the fans if they already arent on.

[LSXfan]

fans are ground signal , fuel pump relay control is 12v+ signal