Starting next week, we are going to make a small update to the v4 PnP harness. This update physically eliminates the o2 modifier feature that most people no longer use. This is because most people:
1) are running with factory catalytic converters OR
2) are using CANclear to suppress cat codes in their off-road use only race cars
Those racers who are using the o2 modifier feature to suppress cat codes shouldn't do this update. Or, better yet, they should should AND get their DME software updated to someone more recent than circa-2007 so that CANclear works
The advantage of this update it two-fold:
1) It opens up 1 analog input and 1 analog output channel. Which we will use at a later date (not saying for what).
2) It removes the o2 sensor wiring in the harness so that the o2 sensor signal no longer has to go into the Procede, get converted to digital, then recreated into analog, then split into two and then sent to the DME. Even when the o2 modifier is turned off in the user software (o2 modifier=100%), there is some some signal processing which is no longer needed. And when we no longer need to process a signal, we should remove it from the circuit.
This can be done with the Procede installed in the car. But for the sake of clarity, we did the work on a table. Locate the Patch harness that has all the fuel control functionality. It is the one with the small black subconnector. If you v4 harness is reasonably new, it will have yellow wires. Look for the pin with the missing wire:
Remove the following wires:
There will be two wires that you remove. One will have a single male end. And the other will split off into two female ends. Make sure the wires you remove look like what you see above.
Next extract two unused patch wires from another subconnector. Your v4 harness has many patch wires that aren't used. You can tell that it's unused by looking at the factory connector that it mates with. If a pin on the factory wire is empty, the corresponding patch wire in the v4 harness is unused. I in the picture below we removed two unused wires the red patch loom. Although you can take wires from any patch loom. Even in the same yellow patch loom. Just make sure it is unused!
Insert new patch wires:
Fold up and tape old wires for later use: