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Discussion Starter · #1 ·
I have a full milltec exhaust w cat delete, and my tips are black and i can def tell its running rich. If i get new upgraded sparkplugs, will this help? Or is there anything else i can do to try to help lean it out?
 

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Not positive this is it, but a cat burns all of the excess gasoline after combustion. Without a cat, there is nothing to do so, leading to all that coming out of your tail pipe.
 

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Discussion Starter · #3 ·
ok do you think upgrading sparkplugs will help or am i just going to have to clean the tip more?
 

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I don't think plugs will do anything. Typically, when you use different plugs, as you increase power, you use plugs that are one, two, or three steps colder, depending on how much power you add. Two great sites to go to are actually FSWerks and CFM, both are sponsors on this site.
 

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I's suggest getting an air/fuel meter and see what's going on at the o2 sensor since the cat is gone.
 

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The Ultra Gauge will not do it.
You need a wideband sensor and an airflow meter.

This is where ECU tuning comes in.
You could use a Piggy Back like I do but it does not work at WOT.
Since you can not change the pulse width, you could reduce the size of your injectors.
But I don't recommend this.

Dave
 

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Wide Band O2 sensor is the only way to determine what is going on. You can Manipulate the O2 Voltage signals by throwing in a Resistor to the signal wires.

But without a Wide Band, you are only guessing
 

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agree, you need a wide band to check this for sure. Running rich is sure safer than running lean.
 

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with this full exhaust, did you eliminate the O2 sensors ? The one closest to the cyl. head controls the fuel mixture. the second one checks on how well the cat is working.

Must be getting all kinds of MIL's.


does Arizona have an inspection law that prohibits removing the cat ?
Federal does.
 

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Discussion Starter · #12 ·
I plugged both of the sensors back in and the second one is throwing a check engine light, but what do you guys recomend for a wideband 02
 

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Personally I would add a highflow catalytic converter with an extender on the rear O2 sensor.

You have to cheat the rear O2 to see what it needs to see. Once you have that sorted, you won't run rich. This is what we do at work to get our tuned cars passed through emissions. It should run much better too.
 

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I plugged both of the sensors back in and the second one is throwing a check engine light, but what do you guys recomend for a wideband 02
You need to keep both sensors plugged in but back the rear one out of the stream a little.
The best way to do this is with a spark plug anti-fouler.
Without a CAT however, you will need to use some kind of O2 sensor simulator for the rear one.
I have not found one that works correctly for this car yet.


As for the A/F meter, I have Innovate.
Universal Digital Tuning Products and Tuning Tools from Innovate Motorsports


Dave
 

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I suspect that the system may not be going into "closed loop". If it remains in "open loop" it will run rich.
When you said "full" exhaust, did you just remove the Cat or does it include a header? I am curious as to where and how you installed the O2 sensors.

More curiosity: since the cat and the manifold are an integral part, how did you remove the cat ?
 

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Discussion Starter · #16 ·
Thanks dave, ill check that out, ice i have the full milltec with the cat delete. And the 4 1 header, so its pretty much strait pipe to the muffler
 

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Curious, I went to the Milltek site to get some info. and they say they don't have a header for the Fiesta.
I am not meaning to argue with you. sites are sometimes not up to date.

Any way, where on the header is the O2 sensor located ? If it is in the collector, it may be too far away to get heat enough to work properly. I have seen this happen on Escorts.
You might contact Milltek with your problem.
 

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Curious, I went to the Milltek site to get some info. and they say they don't have a header for the Fiesta.
I am not meaning to argue with you. sites are sometimes not up to date.

Any way, where on the header is the O2 sensor located ? If it is in the collector, it may be too far away to get heat enough to work properly. I have seen this happen on Escorts.
You might contact Milltek with your problem.
Thank you im from South africa and u just solved my o2 sensor issue not heating up i have to relocate it closer to the flange
 
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