O2 Sensor (Resistor Trick?) EJ22 OBD-II

[TheLoyale]

So, After installing an UEL Header on the Duel-Port EJ22, It throws a P0430 (Catalyst Efficiency) code, Which is normal from doing this mod. My question is, Can you put a proper resistance resistor in between the O2 sesnor and the engine harness to trick the ECU in thinking the sensor is reading correctly?

 

As this thing runs pretty rich (Burns your eyes and nose) and I think its hurting the performence throughout the power band.

 

I have heard of spacing the O2 sensor back using "Spark-plug foulers" but you need to drill them out in order to work, and its a pretty hard compound. So, what options are there to make the ECU think its reading the exhaust gases right so it'll adjust the Air/fuel ratio correctly.

 

I am also getting 18mpg which is a sure sign its running to rich.

 

Thoughts...?

 

-Tom

[GeneralDisorder]

You clearly need a new front sensor since it's reading rich, and you can space the rear one out of the exhaust stream with a non-fouler. A resistor will not work as the signal voltage is very low and frequently oscillates - it's a sine wave and you can't effectively modify the signal in a meaningful way without a sophisticated digital conversion and then a PWM signal generator.

 

GD

[brus brother]

I know I saw someone on an online board who bought the "O2 Sensor Fix" already drilled out on FleaBay but I don't see any for sale that look like the ones in the descriptions below. I asked a friend with a drill press to do mine and it seemed to go smoothly although you could do it freehand.

Here's a how to:

http://forums.evolutionm.net/evo-how-requests-questions-tips/215795-5-o2-cheater-non-fouler-how.html

and a lengthy discussion:

http://forums.evolutionm.net/evo-how-requests-questions-tips/114931-how-install-spark-plug-anti-foulers-remove-ses-cel-light.html

Hope this solves your problem.

PS General Disorder is more knowledgeable than I so follow his lead.

Edited July 12, 2011 by brus brother

[TheLoyale]

I was gonna figure the same as what GD said, figured I'd bring it up and see whats what.

 

I find it hard to believe that the front sensor is now "Bad" as it threw this code right after I put on the UEL Header about this time last year. As I've heard from everyone who runs an aftermarket header, this code is the common problem with running an aftermarket header.

 

So as far as spacing goes, you are only supposed to space the rear sensor out? Also, are the front and rear sensors the same on this? I know on some other vehicles, they use two different styles (Along with connectors)

 

Thanks for the links there Brus.

[brus brother]

From what I've read and been told on this board, you only monkey around with the rear sensor(s).

I have no experience with the mods you did to your engine. Mine was stock all the way.

[GeneralDisorder]

Only space the rear. The front is used for mixture control.

 

They are the same sensor - but with different wireing connectors. Front is triangular, rear is sqaure. Rear for your car is a front for a 90 to 94.... how I know all this is and retain it is beyond me....

 

The code is probably related not to the UEL itself - but the fact that it has no heat sheilds and is longer on some of the runners - causing the exhaust gas temp to drop at the cat and thus not catalize effeciently. You can wrap the header to prevent the escape of heat and possibly get the cat working again.... or you can just punch the guts of it out and run a sensor spacer for $8

 

GD