astolt12

Hey all,

A few months ago I had an issue with my 2011 5.0 where I was having a rough idle, cylinder 1 misfire and general poor performance. Turned out that the one 02 sensor was dead and the other was on the fritz. Took it to the dealership and had them repair it under warranty.

Car ran great immediately after. Definitely solved the problem. The only thing was that I was throwing P0420 and P0430 catalytic deficiency codes as I have high flow cats on. This week some anti-foulers were set to go on the rear sensors before getting bama to tune them off.

Fast forward till today when I go to start her. Right away i get a P0155 "02 Heater Circuit Bank 2, Sensor 1" code. From my lessons before I am guessing that this sensor is dead or inoperable. I was taking her in for some tires this week so I will be adding it to the list for the dealer to work.

BUT...my bigger question is why is this happening again so close to the recent replacement? Is there potentially something in my setup I should be looking for that might be a smoking gun to these things failing? Ford will be replacing this for me under warranty, but I do not really want my car in the shop every month.
- BBK long tube headers (no extensions installed)
- BBK 85mm Throttle Body
- K&N CAI
- Bama 87 Tune

I am fairly certain I do not have an exhaust leak, but I am not 100% sure how to check as those I've spoken to about it have given me varying methods. If y'all have some input on how to check I will glady do such thing.

Also, is there a way to check A/F with the SCT tuner? I've heard that a bad A/F will foul these H02S plugs out.

The car runs fine at the moment. No rough idle, smooth power through the gears and doesn't seem the have an effect on the MPG. This is probably since the remaining 02 sensor is picking up the slack...I just would hate to have to do the same thing I did 2 months ago again every few months.

Any help is appreciated...thanks guys

2005Redfire6

As far as A/F ratio you will need a wideband and then you could datalog with the SCT.

Simon1

I would guess most of your issues are tune related and/or hi flow cats.

Have you spoken with Bama?

tx_zstang

The O2 code after sensor replacement could very well be an issue with the sensor they put it, or it came unplugged or a wire burned through.

Aren't the front sensors wideband sensors in your 5.0? Definitely not the same as the narrow-band ones in earlier years.
The tune could also be affecting the 'diagnosis' of your front sensor's operational integrity.

The 420/430 are due to the high-flow cats. I'd try the anti-foulers first. This should be unrelated to your front sensor issues.

scottmach

The front o2's are widebands making it very easy to data log these cars.

astolt12

I'll have to get bama involved after everything gets touched up. I've seen some horror stories on their tunes throwing the wrong AF mixture. I generally do not run it hard, so I'm not worried too much but I want to know that when that pedal hits the floor all is good!

The one thing I wish the 11s had was the center read out, so I might look into a wideband gauge that can scan the systems.

Thanks though, any other thoughts???

astolt12

Update All

Was told during the repair process that my ECU's computer was missing an update which caused this to occur?

I basically understood it as the ECU was missing a factory firmware update and somehow under stress caused the heating element on the o2 sensor to fry. They updated it for "free" but i do not see the call out on the repair sheet.

My bigger question now is when i get back with bama and reflash it to my configuration will the "updated" stock ECU file be uploaded onto my SCT?

Sounds like some malarky to me, but I am not up to speed/understanding with the newer ECUs...just give me a carburetor!!!

moosestang

You may need a new tune if they flashed your ECU. Talk to AM before you try to reflash the tune.

astolt12

Will do moosestang. Always a help, thank you.

astolt12

All,

I wanted to circle back on this for anyone who is running long tubes and may be experiencing the blown Bank 2 sensor 1 issue like myself.

I noticed that after every rainstorm the car would sputter. I was fortunate enough to have a set of aeroforce gauges to monitor the A/F on the car. In doing so, that sensor's A/F ranged from 11-22 at idle, making the car feel pretty darn choppy while the other was perfect at 14.5-15.0.

So i decided to do a test filling up a cup of water in the garage and dumping it on my window. The water rolls through the internals and eventually gets routed to a drain pipe on your firewall - this thing was dripping directly on the H02s' connection. Now, yes they are supposed to be water resistant/proof but when they shop last put it in they busted the weather stripping allowing for water to enter and give the erratic voltage readings.

Essentially the wiring was moved toward the rear of the car and some weather stripping was put over the connection after buying (hopefully) the last new H02s sensor.

So long story short, if you're blowing 02 sensors with long tubes you might want to check that connection! This was all routed without using any extensions. Ontop of the transmission there is a nub that holds it place for wire routing - pop that off and you'll have plenty to use.