I have a 97 F150 4.6 V8 a few years ago I had the bright idea to remove my second set of cats, leaving the elbow cats on. Well while under there getting hot shavings on my arm and guarding my face I didn't watch how I was cutting. The cut came out pretty crooked. The top is fine but the bottom slants towards the o2 sensor bung. Ever sense I have not been able to clamp a replacement pipe on there correctly because it doesn't grab the bottom part. I finally got tired of the loud drone in my truck and the annoying sound of the exhaust leak so I figured I'd try to figure something out. I came across a Mil eliminator so I figured I could just cut past the o2 bung and run a straight pipe, remove the o2 sensor and do the mil eliminator. These are the steps I followed. 1) pulled the sheath over the loose o2 wires down so I could access the wires 3) cut the gray wire and put a 1m ohm resistor inline.
3) exposed the bare wire on the black lead and ran the 1.0uF capacitor from the black to the gray on the conector side of the resistor, positive post on the black wire. 4) zip tied the o2 sensor to my chasis plugged it back in and went on my way. once the truck heated up cel on with the code PO136 bank 1 downstream which I guess is on the passenger side. So I decided to try disconnecting the negative cable for 10 mins then putting it back on, drove to work and no CEL. I left work and drove a while and there it was CEL. any suggestions on what I might have done wrong besides making the stupid decision of cutting my secondary cat off? anything would help
thanks

 

P0136 Heated O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
sorry to say it but you more than likely screwed up that o2 sensor. you should never do that to a sensor. as long as its a circuit malfunction and not a rich or lean code then its not going to affect fuel mileage but eventually it may run weird. but you can buy a new o2 fitting and have someone weld it in for you and you can put your sensor right in.

 

people do it all the time just trying to find someone with a little knowledge ab it that might be able to give some input. mostly stand owners

 

Pardon me , but NO , No one does that to B1S1/B2S1 - Your nutts if you think so. PO136 = B1S2 - Which one are you even talking about?

You probably have chicken wire holding up your exhaust as well

 

Bank 1, sensor 2 is your secondary o2 sensor on the passenger side right?
Google, Mil eliminator, plenty people make and sell the exact eliminator I am talking about, programmers eliminate rear o2 sensors. The only reason I am getting the PO136 is because i was told once doing the mil eliminator was installed it would work either way, in or out of the o2 bung. I didn't do it to try to fix the PO136. Maybe you should look around before making an assumption. What's the point of being subscribed to a forum if you just choose to be a ***** to someone who has less knowledge on a subject than you do and is looking for some advice? Didn't know I was the first to eliminate my rear o2 sensors... http://www.paladinmicro.com/MustangMILEliminator.htm there's just one example since no one does that to there rear o2 sensors.

 

jbrew, you choose to be a ***** about my question but then again you post the same solution to someone else, only difference is I wanted to remove the o2 sensor instead of keeping it screwed in and ran into a problem.
https://www.f150online.com/forums/ex...iminators.html

 

You made it sound like you were rigging the front sensors. PO136 doesn't necessarily come from the rear. The person in that thread you posted Knows how to ask a question. Go back to school.

 

I clearly stated that it was bank 1 downstream, I asked the question correctly maybe it was the reader... You obviously don't know your dtc codes too well either. PO136 is bank1 sensor 2, sensor 2 is clearly your rear sensor.
P0136 = O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
Looks like that specifies exactly which one it is, last I checked PO136 didn't mean O2 Sensor Circuit Malfunction with no location of which one.
That is why there are multiple DTC codes to target exactly where there problem is. Here is a list of the o2 sensor dtc codes to help you with your ignorance.
# P0130 02 Sensor Circuit Malfunction (Bank I Sensor 1)
# P0131 02 Sensor Circuit Low Voltage (Bank I Sensor I)
# P0132 02 Sensor Circuit High Voltage (Bank I Sensor 1)
# P0133 02 Sensor Circuit Slow Response (Bank 1 Sensor 1)
# P0134 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)
# P0135 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
# P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
# P0137 02 Sensor Circuit Low Voltage (Bank I Sensor 2)
# P0138 02 Sensor Circuit High Voltage (Bank I Sensor 2)
# P0139 02 Sensor Circuit Slow Response (Bank 1 Sensor 2)
# P0140 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
# P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
# P0142 02 Sensor Circuit Malfunction (Bank I Sensor 3)
# P0143 02 Sensor Circuit Low Voltage (Bank I Sensor 3)
# P0144 02 Sensor Circuit High Voltage (Bank I Sensor 3)
# P0145 02 Sensor Circuit Slow Response (Bank 1 Sensor 3)
# P0146 02 Sensor Circuit No Activity Detected (Bank I Sensor 3)
# P0147 02 Sensor Heater Circuit Malfunction (Bank I Sensor 3)
# P0150 02 Sensor Circuit Malfunction (Bank 2 Sensor I)
# P0151 02 Sensor Circuit Low Voltage (Bank 2 Sensor I)
# P0152 02 Sensor Circuit High Voltage (Bank 2 Sensor 1)
# P0153 02 Sensor Circuit Slow Response (Bank 2 Sensor 1)
# P0154 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
# P0155 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
# P0156 02 Sensor Circuit Malfunction (Bank 2 Sensor 2)
# P0157 02 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
# P0158 02 Sensor Circuit High Voltage (Bank 2 Sensor 2)
# P0159 02 Sensor Circuit Slow Response (Bank 2 Sensor 2)
# P0160 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
# P0161 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
# P0162 02 Sensor Circuit Malfunction (Bank 2 Sensor 3)
# P0163 02 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
# P0164 02 Sensor Circuit High Voltage (Bank 2 Sensor 3)
# P0165 02 Sensor Circuit Slow Response (Bank 2 Sensor 3)
# P0166 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
# P0167 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3)
Here I pulled this definition off of google since you had a problem understanding what downstream was.
Rear (downstream) oxygen sensor
Rear or downstream oxygen sensor located after catalytic converter. It monitors the efficiency of the catalytic converter.

 

At least you can copy and paste. No you didn't state you were destroying and rigging the downstream sensor in particular. The code those sensors are responsible for are PO420 & 430 - They are efficiancy checkers.

PO136 is from YOU screwing up the wires, plain and simple. You don't know what your doing, so you should leave the sh^t alone IMO.

But, My bad. I could have figured it out earlier. I apologize.

 

there is my original post and me stating it was downstream. if everyone knew everything they were doing then no one would post on the forum, i expected some help not someone to give me a smart *** comment, basically telling me i'm an idiot and being disrespected for trying to learn. i'd much rather learn something myself then be like most of the people my age and younger who don't know what end of a hammer to use. i read information and did my connections right and obviously got wrong information about the mil eliminator still working without the sensor being plugged in. don't mean to be a **** myself but i don't give respect where respect isn't given. i've been coming on this site for about 2 years and read alot of things you posted and would of never expected someone with the knowledge you have to give an response like you did.

 

Yea, Ill take a hit on this one. So get it all out ..

Are you running front cats ? If so , why are you even messing with the rear sensors ? If your forward cats are good and you have no leaks in your system , there is NO need to modify your O2's - Any of them.

That's what you need to realize.

BTW - I've done it on a 98, I really like the sound when I use to run this way. It mimicked the older GT's when driven normally. It can't leak tho. I press fit it together. Here's the set up -

 

You will not deviate from set parameters with this set up when done right. Your well within margins.

Problems that may occur.

1. Seam leak (most common)

2. O2 Bung leak ( common in older vehicles )

- a.) When removing an O2 sensor from the bung to clean or replace, it's easy to take a few threads from the bung with it - or partly strip the bung. This will cause leaks and a CEL.

The fix can be accomplished by using RTV Gold w/copper by Permetex if damage is not to severe.

 

nice setup.... I do still have my front cats, but when I removed my second set of cats I was in a rush already had some trouble with some other stuff and just got it done real quick while it was getting dark. When I cut them I started the cut far enough from the o2 bung to run my new pipe but it wound up on a slant and the bottom of the pipe was just too short for me to get a clamp on. So, when I put my clamp on it would tighten the top but cause the bottom of the clamp slide off the existing pipe and cause the new one to open up causing a leak. Besides the sound of the leak the torque lost when driving and hitting the gas began to be a problem. I figured I'd cut off the bung and run a straight pipe and do the o2 mod. Well, it obviously didn't work out as plan. I do plan on redoing the complete exhaust just needed a fix for now until I get a welder and figure out exactly what configuration I want to go with. I got a fix thought, I picked up a pc board, a 555 timer and some other components and I am just going to make a simulator right now so I can get the input voltage to fluctuate. I know it will be somewhat of a rig for now but it's just a temp fix. My voltage should fluctuate between 0v - 0.4v on my rear sensors is this correct?

 

what type of muffler did you put on that and is that 3"? i love the gt sound and that's what i'd wish to accomplish when i do my exhaust

 

Not sure, I haven't messed with the computer. I would rather get the exhaust fixed - Less headaches IMO. Plus I use the truck for pulling, so I need everything working within stock parameters.