2001 4runner ECU Patch Harness DIY?

[4RunnerNoobinNC]

I recently SC’d my ‘01 RWD daily driver 4runner. My intentions were to keep things super simple…slighly smaller 2.3” pulley, IK22 plugs w/ new OEM wires, new OEM fuel filter, boost gauge and cleaned TB & MAF. It’s been about 5k miles since it was installed and no pinging thus far. However I have noticed it leaning out at highway speeds if I don’t pay attention to what gear I’m in (auto trans). I’ve spent a LOT of time researching upgrade options bc I have been bitten by the “more power” bug.

So now to my question…

I know URD sells patch harnesses for the ECU (which from the pics appears to be the same as Autosport Wiring’s harness). $200ish for a harness isn’t breaking the bank by any means, but I wouldn’t mind making my own. Has anyone made their own? Where can I get the supplies? I’m assuming the plugs needed will come from Toyota? What size/type of wire is needed? If anyone could point me in the right direction, it would be greatly appreciated.

Also…I wanted to give a HUGE THANKS to all the 3rd Gen guys that have put the time and effort into supplying the vast amount of info on the forum. I’ve spent 3yrs and 100,000mi lurking before making my 1st post, and just wanted to show my appreciation to everyone!

 

[phattyduck]

I mean, how much is your time worth? That's a LOT of pins - and to do it reliably in a quality manor takes time. I bet just the parts (4x harness side connectors + 1 ecu side connector + wire/heat shrink) is probably over $50 already. I would expect multiple hours to get it done (like 3+, plus research time)

It does match the layout of at least one other Toyota (one generation / engine configuration from a Supra, I think?) so it is possible to find the parts outside of the Toyota dealer supply chain.

-Charlie