Look at this schematic for my O2 sensors...

[joeventura]

Which wire is the computer signal wire?
Want to know which to cut into to inject voltage from EFIE

This is a Mits 2004 Galant ES



Thanks for any help.

[joeventura]

Here is a close up, looks like the pic quality is bad:

[GasSavers_RoadWarrior]

The two plates with the arrow look like it's the "variable cell" and that side is shielded, so I'd figure the white, pink, green and yellow wires were the outputs. The other side must be the heater.

[joeventura]

Ok I will shave into one of those and see what the meter shows.

If anyone else has any feedback, I would love to hear it.

and thanks RoadWarrior!!

[joeventura]

Is it surprising that a Mits 04 has 4 O2 sensors before the Cat?

I was very surprised to learn I would need to dual EFIEs (ugh)

[GasSavers_RoadWarrior]

Well it allows better control of fuelling on a per cylinder basis... 1 and 4 on most 4cyls are reckoned to tend to run richer than 2 and 3, so it would solve that issue. Also if one cylinder goes lean due to a bit of dirt or varnish in an injector it's not going to hose 20% more fuel in the other three cylinders trying to compensate.

[GasSavers_peter]

This is a 3.8 liter engine (6 cylinders), so it actually has 2 pre-cat O2 sensors and 2 post-cat sensors (catalyst monitors) for each bank of cylinders...I was looking on mitchel on demand and it doesn't really get in to what wire goes where, but if you're going to tap i, i would go with the 2 front o2's and i would get an automotive dvom and check voltages with key on engine off. the 12v + would be for the heater circuit...

[joeventura]

My car and the schematic I provided is from the 2.7 L 4 cyl engine actually.

Are you saying for purposes of applying an EFIE I should go with the front two ONLY?

Thanks

[joeventura]

Originally Posted by RoadWarrior

The two plates with the arrow look like it's the "variable cell" and that side is shielded, so I'd figure the white, pink, green and yellow wires were the outputs. The other side must be the heater.

You were correct, checked it this evening and that wire was fluxing between .1 and .9 volts. Very cool

Anyone have an opinion on whether I need a DUAL EFIE for the lower (rear)
O2 sensors?

Thanks to all!!