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YellowJellyBean 05-12-2010 09:16 PM

Additional hole for AEM wideband?
Hey guys. Just ordered my tune from Tom. At his suggestion, my next plan is to get an AEM wideband A/F gauge. I see that my car has 3 O2 sensors, do I need to make an additional hole for a 4th one, or do I simply remove the stock 3rd O2 sensor and replace with the AEM one? Thanks!

1turbofocus 05-12-2010 09:26 PM

Remove the second o2 and use that hole


YellowJellyBean 05-12-2010 09:29 PM

All right, thanks Tom. Super helpful as usual.

Defiant 05-13-2010 12:07 AM

I have a question, talking about O2 sensor...
I have a Zetec 2.0L and I'm getting a new stainless steel custom header, they're asking me in which "cylinder" I prefer to use the O2 sensor. Any of them is fine? Does my car has more than one O2 sensors?


BC_ZX3 05-13-2010 10:27 PM

To answer your second question first, your model year of car should have two O2 sensors - one after the exhaust manifold and just before the catalyst, and one immediately after the catalyst.
Your first O2 sensor should not test the emissions from one particular cylinder/exhaust runner; it should be located in a spot just after where all the pipes converge i.e. in a 4-2-1 header setup, the O2 sensor should be after pipe "1". Have a look at the stock SVT exhaust set up.
If you are converting from a stock Zetec manifold, it is a simple case of extending the O2 sensor wiring harness to reach the new sensor location further downstream. Ford (and others) sell an extension for this purpose.

Defiant 05-13-2010 10:51 PM

And what happens if I removed the catalyst? Where would that sensor go?


BC_ZX3 05-13-2010 11:04 PM

Even if you remove the catalyst, the front O2 sensor is required. The rear O2 sensor can be deleted. (The rear O2 sensor monitors the efficiency of the catalyst.) In other words, remove the rear physical sensor, tie up the wiring harness connector out of the way and have a tuner like Tom disable the rear O2 sensor functionality so you don't get a CEL.

Then plug the second hole or use it for your wideband sensor.

Defiant 05-13-2010 11:21 PM

Ok I got it! Thanks a lot!


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