I am a proud owner of a 2001 Expedition 4.6. I have a Lightning style H-Pipe welded on it starting just behind the back cats on both sides with American Thunder Flows. What I need help with is that I am buying some Mil-Eliminators (I have a set on my 98 Cobra), Summit has a set for around $60 bucks, but I need help on where they go, I am not familiar with the Expedition like I am with the Cobra. Would they go were the front cats sensors are or on the back were the back sensor would be? I intend on putting on my BBK headers this week end, and I really want to get rid of those cats. Any and all ideas/suggestions/experiences are welcomed.
The part number on Summit is: BBK-1675

 

they would go behind the cats.the sensors behind the cats tell how efficent the cat is working.if you tack the cats off the down streem sensor think that the cats arnt performing there job so it sets a down stream o2 code.

 

That makes alot of sense, now that I think about. Now my only question is, will these particular Mil-Elims work? I do know how to put a picture of them on here yet, but the part number is: BBK-1675
When you get the time, could you please look on the summit web site and look at them? Today when I get home, I am going to look at the ones on the truck to see If I tell if they will work. I noticed your an ASE Cert. Mechanic in your sig, so if you tell me either way, I would be 99% confident in your answer. Thanks in advance.

 

$60 bucks is about twice too much! Save your money and buy these. Had them on my Crown Vic for a couple of years ...... no problems.
http://www.ponyexpressperformance.co...iminators.html


........and here's the instructions.
http://www.ponyexpressperformance.com/MMILinstall.html

I only use my Crown Vic off road, of course.

 

Those look very straght forward and simple to install. You said you had them on your Crown Vic? The rear o2 sensors will be obviously be of no concern, just put them back in the bung after splicing and header install, but would it make any difference If I put new 02 sensors in the front?

 

Bad converters / bad or no rear O2 sensors will throw P0420/P0430 codes. Do you have any other codes? I wouldn't replace the fronts just for the heck of it.

 

No, no codes, just completing my exhaust. It sounds mean now for an Expedition, just want to get that FULL HEADER EXHAUST note. So you think the front two are ok? The truck has 129,000 miles on it, with 8,000 miles on the Sean Hyland Motorsports bottom end. It is being prepped for a Procharger P1SC, you follow me now It is only lowered 1inch front and rear (not slammed- I hate that), 18x10 polished aluminum wheels with 305/50's front and rear, lightning front bumper, some goodies on/in the motor and 5% on all windows, the truck is Dark Maroon.

 

Depending on the brand, expect $60-$125 each for the sensors. Only you can say if it's worth it to replace them to assure against near future failures. If I build an engine for ME, I replace the starter, alternator, water pump, belts, hoses, and anything else that could fail in the forseeable future. Not having to worry about a failure has it's cost.
Spending YOUR money ....... heck yeah I'd replace 'em!

........and I like the dark maroon!

(edit: Y2K Ford Parts, a sponsor here, lists the sensors for $47.99. A deal!)
http://www.trademotion.com/partlocat...del=Expedition

 

Yeah, I agree with you on the belts, water pump, alternator and stuff, all new except for starter. I even have MSD COP, all 8 setting on top of ACCELL Plugs.
Nice lumpy cams, forged bottom end (8 to 1 - for SC), BBK Throttlebody and so on. Anyway, my exhuast is the only thing left of this expansive puzzle I have put together. My goal is (don't laugh) is 400hp/450+tq to the ground and maybe high 12 in the qtr mile. (My Cobra does low 11's-all motor 32v). But yeah, I thougt of that too before I started the build up, replace all of the other parts along with the motor upgrades. I would hate to build a $8,000 motor and be haulling a** and my water pump or oil pump to go and waste all that money. I will go ahead and erplace those 2 front o2 sensors to be safe, after said and done, the only thing left will be a Dyno tune.
Oh BTW, it will bark 2nd gear, pretty hard too

 

 

yea a deal!

www.fordpartsguy.com

www.discountfordpartsaty2kford.com

www.fordparts-fordparts-fordparts.com

www.y2kfordparts.com comming soon

I have a few more if you want them. LOL

Ed

 

with 130k on the clock, I would replace all 4 of them.

One thing to remember, MILs only work if you have a good set of working O2's.

 

The rear ones I am not to worried about, the Mils will make them useless, there just to plug up[ the holes in the pipe. The front ones, your right, I have already bought new ones. After the headers and pipe are ran and welded to my H-Pipe, I will try to figure out how to put a sound sample on here. I sounds great now, but, it is a truck, I want it LOUD, not that straght pipe BLAAAHHHHH Sound, but a good "tuned" rumble loud. I think you know what I mean.

 

Do as you will, but you obviously do not understand how MIL's work. Read this short article on how O2's work;

Most peeps do not understand what makes a MIL work, they just think that the MIL itself makes the sensor "mute". All a MIL is, is a 1/4-1/2 watt resistor and a capacitor. It takes the output provided by the sensor and reduces the output by 25-50% bringing the "new" output down to acceptable levels. So, if you have a good working sensor and no cats, your going to read above 600mV, the mill will reduce that output to the 300-600mV range (the acceptable range). If your sensor is bad or going bad there is no telling what it might give as an output. For example; A "bad" sensor might give you a 300mV reading with cats in place, this is an acceptable reading and the computer will not give you an SES for it even though its on the verge of an unacceptable reading. But if you removed the cats it spikes to 450mV (still a good output, but you do not know that) and you install MIL's, now you reduce the signal to 225mV and set the SES light off. This example is not uncommon and I see it alot in the Mustang world. But you get the point.

In short, if your sensors (after cat, i.e. rear sensors) are slow, going bad, etc. then your MIL's will not work properly and at 130k you can assume that they will fail sooner than later, thus making your MIL's useless and giving you an SES light.

Now all that being said, I noticed you were going to get a "tune". As long as you do not have emission testing in your area, you could have the rear O2's "turned off" with a tune. If you do have testing in your area, then you will need MIL's as the test machine looks for working rear O2's.

So, your call, just trying to help you out.

 

I just got spanked... Great thread, you know your stuff on exhuast and sensors. Your right on the tune, but I did not want to go to extreme on it, I thought I could just put some Mils on there and be done with it. Seriously, thanks for the heads up, that good info. That should be a sticky if it is not already. I will order the rear two as well, Summit can have them here in the morning for me. Again, thanks man.