Minimum wire harness for engine operation?

[fnkngrv]

Can't wait to see how this pans out for you

[CrankyOldMan]

Originally Posted by fnkngrv

Can't wait to see how this pans out for you

It won't be anything terribly exciting at first, just comparable to stock engine performance. After that, though, sky's the limit!

Originally Posted by CTScott

There are 4 connectors which go to ECM on the Echo.

Correct. The photos of the main engine wire harness clearly show three connectors on the interior side of the main grommet (E5-E7 if I'm not mistaken) that are grouped to go into the ECU, but there's a separate tendril between the ECU and the grommet with two more white high-density connectors that I can't clearly differentiate from the diagrams in the EWD. The newer Toyota EWDs use color-coded images for each separate wire harness, but this old one is just B&W, so the actual routing gets lost in the image compression.