Now its time for wiring. This is what most people want to know. You will want to wire it as a 2002 Express van with a 5.7. You will have to run 3 wires(4 if you turn on the electric fan pin). 2 injector grounds and a single wire knock sensor.
First thing you will need is some pins for the computer. You will get 2 off the old knock sensor pins, but you still need 2 more. Junkyard is the best place. Just cut off a whole computer harness.
Here is the injector pinout you will use. I am not going to resize it so it is easier to read.
The easiest way to do this is just swap the pics at the injector plug. You have to change it to the v8 one anyways. Just make sure the correct pins go to the correct injector. The pink wires are the 12v positive. Just splice the 2 added pink injector wires into any other pink.
And just in case the photo dissapears...
Injector 1: pin 36
Injector 2: pin 3
Injector 3: pin 4
Injector 4: pin 43
Injector 5: pin 76
Injector 6: pin 37
Injector 7: pin 44
Injector 8: pin 77
Now the knock sensor. Go to the hardware store and get a 1/4 brass NPT elbow. The knock sensor will not clear the motor mount unless you add the elbow.
The knock sensor will go to pin 51.
You will need Express Van O2 sensors, the Bosch part number is 13474.
My O2 sensors were taking forever to warm up, so I measured heater voltage at the O2 plugs and had zero. After a review of the wiring differences between the 2002 S10 and a 2002 Express van, I found that the S10 O2's used a PWM heater circuit driven by the computer, and the Express van O2's were just plain old fused 12V that are on anytime the key is in the run position. Well that explains it. Just the simple flash to the Express van OS in the computer makes them not work. This all comes back to the s10 using signal ground O2's, and the express van using case ground.
O2 heater wire pins on 02 S10, these pins are in the red plug:
Pin 74: O2 B1S1 and B2S1 high(+12V positive)
Pin 80: O2 B1S1 and B2S1 low(ground)
Pin 72 O2 B1S2 low(ground), after cat
The after cat O2 has its own 20A fuse in the underhood fuse box. I simply spliced into that wire at the fuse box plug, and ran it in the harness and tied it to the wire that was in pin 74. This 20 amp circuit should be more than enough to carry all 3 heaters.
The 02 Express van diagram showed the ground for the heater circuit tied into the alternator bracket, and sure enough there was a ground point on the side. so I ran the ground(pin 80) to this point, and finished it with a ring terminal.
This morning on a cold start it took about 5 seconds for my O2's to start switching, where before it took a good 3-5 minutes. And it really changed my fuel trims...for the good.
You will also need a mass air meter from the 5.7 engine. The 4.3 one will not work unless you tune it in.
And if anyone wants to review the ECU wiring diagrams all this info came from, here they are.
Various years S10:
And the Vortec 5.7 0411 computer diagrams: