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Discussion Starter #1
Great,so I install the 4-2-1 header,2 1/4 Flex and a MIL eliminator on my 02 atx ZX3 on Sunday.
47 miles driven and I got the CEL.
MIL installed in lower 02 sensor,everything else appears correct.
No leaks heard,Car still runs Good....just overbearingly loud at this point.
Going to try and get it checked at Auto Zone in the morning.
Any ideas what it could be before I do?
Are MIL's really that undependable?
I read in an older thread that someone's MIL causes the CEL once a month.
Will a tune fix this?
I may be getting one sooner than planned if so.....
 

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I would think that a tune would get rid of the CEL.

let us know more and I bet someone would figure it out for you
 

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Discussion Starter #4

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DTC P0606
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What kind of MIL eliminator are you using? A pre-made one or did you make one up yourself? Until you get the code read, you're assuming it's a rear O2 sensor code. Might not be; could be a coincidental CEL.
A tune would definitely fix a "catalyst efficiency below thresh hold" or rear 02 sensor failure CEL.
 

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Aurelius Pardus
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sometimes they just don't work either...... all you're trying to do is move the 02 out of the direct flow of the exhaust, meaning it could still be bad enough to think the cat is not doing it's job.

I'm expecting to see P0420.

If it's one of those that I think messes with the signal to make it read within the normal range then maybe it's just not working right.
 

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Discussion Starter #7
What kind of MIL eliminator are you using? A pre-made one or did you make one up yourself? Until you get the code read, you're assuming it's a rear O2 sensor code. Might not be; could be a coincidental CEL.
A tune would definitely fix a "catalyst efficiency below thresh hold" or rear 02 sensor failure CEL.
Yep,its a premade one from CFM.
 

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Discussion Starter #8
Just got it checked and came up with code:
P0171

PO171---- System adaptive fuel too lean (Bank 1)

???
Help?
 

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Discussion Starter #9
From a different thread:

P0171/P0174

Examples: MAF sensor measurement inaccurate (corroded connector, contamination/dirty (a contaminated MAF sensor will typically result in a rich system at low airflows (PCM will reduce fuel) and a lean system at high airflows (PCM will increase fuel), etc).

Vacuum Leaks/Unmetered Air:
With this condition, the engine may actually run lean of stoichiometry (14.7:1 air/fuel ratio) if the Powertrain Control Module (PCM) is not able to compensate enough to correct for the condition. This condition can be caused by unmetered air entering the engine, or due to a MAF malfunction. In this situation, the volume of air entering the engine is actually greater than what the MAF sensor is indicating to the PCM. Vacuum leaks will normally be most apparent when high manifold vacuum is present (for example, during idle or light throttle). If freeze frame data indicates that the fault occurred at idle, a check for vacuum leaks/unmetered air might be the best starting point.

Examples: Loose, leaking or disconnected vacuum lines, intake manifold gaskets or O-rings, throttle body gaskets, brake booster, air inlet tube, stuck/frozen/aftermarket PCV valve, unseated engine oil dipstick, etc.

Insufficient Fueling:
With this condition, the engine may actually run lean of stoichiometry (14.7:1 air/fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition can be caused by a fuel delivery system concern that restricts or limits the amount of fuel being delivered to the engine. This condition will normally be most apparent when the engine is under a heavy load and at high rpm, when a higher volume of fuel is required. If freeze frame data indicates that the fault occurred under a heavy load and at higher rpm, a check of the fuel delivery system (checking fuel pressure with engine under a load) might be the best starting point.

Examples: low fuel pressure (fuel pump, fuel filter, fuel leaks, restricted fuel supply lines), fuel injector concerns, etc.

Exhaust System Leaks:
In this type of condition, the engine may actually be running rich of stoichiometry (14.7:1 air/fuel ratio) because the fuel control system is adding fuel to compensate for a perceived (not actual) lean condition. This condition is caused by oxygen (air) entering the exhaust system from an external source. The HO2S will react to this exhaust leak by increasing fuel delivery. This condition will cause the exhaust gas mixture from the cylinder to be rich.

Examples: Exhaust system leaks upstream or near HO2S, poorly welded/leaking HO2S boss, malfunctioning Secondary Air Injection system, etc.

My Car has always idled very low...
Should I check vacuum leaks first?
Im not going to drive it to work today.
Going to let Her sit and use the wife's Freestyle.
Any ideas,please post them up,I cannot respond back till later tonite.
Help and input appreciated!
 

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Discussion Starter #10
Also before leaving for work:
All o2 sensors appear to be hooked up fine.
I don't know where to begin looking for vacuum lines.
The only thing I saw that's a concern is the hose leading from the valve cover to the Steeda SRI does not appear to have a smooth bend...its not kinked,but looks to be a sharper angle than I like.
Help!
 

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Discussion Starter #11
Hose all jacked up?


o2 sensors tight....


wtf?Oil laying on top of new Contour valve cover?
Doesn't look like it got down into the plug boots...whats the torque specs for the valve cover?
 

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DTC P0606
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Check for vacuum leaks at the intake manifold end from your EGR pipe/fitting. If you had to bend your EGR pipe you may have applied a bit too much torque and inadvertently created a leak. I'm guessing, of course...
After the header install, did you pull the battery cable to clear the ECU adaptive fuel strategy settings? Might be worth trying. The DTC code will probably re-occur.
VC torque specs are 60 inch-lbs or 5 ft lbs. "Snugging" them down is usually sufficient if your torque wrench doesn't go that low.
P0171 codes are usually vacuum leaks. Check the PCV hose, just for laughs.
 

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Discussion Starter #14
Check for vacuum leaks at the intake manifold end from your EGR pipe/fitting. If you had to bend your EGR pipe you may have applied a bit too much torque and inadvertently created a leak. I'm guessing, of course...
After the header install, did you pull the battery cable to clear the ECU adaptive fuel strategy settings? Might be worth trying. The DTC code will probably re-occur.
VC torque specs are 60 inch-lbs or 5 ft lbs. "Snugging" them down is usually sufficient if your torque wrench doesn't go that low.
P0171 codes are usually vacuum leaks. Check the PCV hose, just for laughs.
Thanks...
I just started a new thread but may have found the culprit.
I looked again at the oil on top of the Contour valve cover after not finding any noticeable cracked/split vacuum lines.
I pulled spark plug boot number 2 and could not even see the plug as there was that much oil covering it.
Either the Gasket failed or the bolts are over torqued.
I think I read that a po171 can also be caused by misfire.
I didn't feel or hear a misfire,but maybe it was just enough to trip the CEL.
Could this be the cause?
 

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BACON?
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yes a misfire can cause a lean reading. An oxygen sensor can only read oxygen. this means that when misfiring, instead of the oxygen being consumed by the burning fuel, its pumped straight in to the exhaust. the Air fuel ratio could still be correct, but there is no way to tell how much fuel is in the exhaust with the oxygen. I am pretty sure an incomplete burn would create the same situation. Lots of carbon monoxide (CO) produced , leaving the extra oxygen that would have become CO2.
 

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Discussion Starter #16
yes a misfire can cause a lean reading. An oxygen sensor can only read oxygen. this means that when misfiring, instead of the oxygen being consumed by the burning fuel, its pumped straight in to the exhaust. the Air fuel ratio could still be correct, but there is no way to tell how much fuel is in the exhaust with the oxygen. I am pretty sure an incomplete burn would create the same situation. Lots of carbon monoxide (CO) produced , leaving the extra oxygen that would have become CO2.
I am sucking oil out of the spark plug wells with a turkey baster right now....
Got about half a quart,which makes sense:
My Pop changed my oil as I was running late to go to work the day we swapped the valve cover and lo and behold,He overfilled it by about half a court.
Think I'm still going to swap the gasket anyway tomorrow.
Pulling the negative battery terminal going to see if the Cel pops right back up.....
OMG....just found at the bottom the pcv hose is collapsed!
This just gets better and better!
 

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Discussion Starter #17
Had to pick up a new PCV tube from Ford directly as its a dealer only part???
This little tube cost Me 30.00!
FML...
Going to install tomorrow or Sunday and see if this along with the new Contour gasket fixes the CEL.
Wish Me luck.
 

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Discussion Starter #19
Good luck, you sure did open a nice can of worms there.
LoL
As annoying as this all is,its still very cool.
I Love My Foci....but it always seems to go like this.
Change something only to have something else flare up.
Will keep updated as I cant stand threads that the op never responds back to for the end result.
I am pretty confident that the pcv tube is the reason behind the CEL and the low idle and bog off the line.
Cross your fingers.....
I'm going to spank that Focus into submission:
[smackbum]
 

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i got a misfire code from the oil in my plugs clean them clear the computer change the gasket and u should be good to go. worked on mine.
 
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