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Old 10-04-2010, 09:56 AM   This thread is in the EcoModder Project Library | #1 (permalink)
EcoModding Lurker
Join Date: Sep 2010
Location: Ovid MI
Posts: 45

Niner_xA - '05 Scion xA
90 day: 35.82 mpg (US)

Horse Hauler - '95 Ford F-250 XLT
90 day: 13.47 mpg (US)

Butterkup - '02 Mazda Miata
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Adding injector cutoff to a Scion xA

This directly applies to the 04/05 xA, but may work similarly with the '06 or gen 1 xB.

The fuse that protects the injectors in the xA also protects a lot of other things that I don't want to turn off when I kill the engine for EOC. Luckily, I found a very good wiring manual for the xA that traces the path of the wire from the ignition switch. There was a good location to find the wire I needed in a harness plug directly behind the glovebox. I wanted to just run a normally-closed switch across this wire, but couldn't find something rated high enough for my tastes at the local Radio Shack, so I went with a relay.

Button on front of shifter - one end goes to ground, one to the relay:

Behind the glovebox of the xA:

The appropriate connection - the injector power line is the black wire with the red stripe on the far right:

My small relay board - the always-hot side of the injector power goes on the bottom screw terminal, otherwise the relay will oscillate:

And... the day I installed this and used it, I got a CEL. My first guess is that it senses the injectors "failing", although the CEL was gone this morning and I did use EOC once. It's possible I underrated the relay I needed, so if the CEL comes back I'm going to get it decoded at the auto parts store. In case of relay failure, I have a crimping tool and some butt connectors in my car anyways.

Hopefully this helps someone else.

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The Following 4 Users Say Thank You to Niner For This Useful Post:
daring4 (03-26-2013), NeilBlanchard (10-04-2010), SentraSE-R (07-04-2011), Weather Spotter (10-14-2010)