'12 Shelby w/ random o2 failure - PCM on its way out?

[JeremyAlan]

So as you can see by the thread title I have a 2012 Shelby that I'm working on(gf's car). We had it on the dyno the other day and the Bank 2 Sensor 1 flatlined at 0.00, intermittently it would come back and read A/F for a few minutes then back to nothing.

I went to trouble shoot the problem today and while i was driving it down the highway when they both began reading, shortly after Bank 1 Sensor 1 flatlined. So, the problem switched sides for no apparent reason. I pulled over into a parking lot and continued to watch the aeroforce gauge. While idling the B1S1 would momentarily return with an A/F reading, then turn off again. I drove the car home and the B1S1 would read for about 1-2 minutes at random and when it did the reading was fluctuating wildly from -2 to +4 of the B2S1 sensor.

Also, as a side note every time i start the car it has a check engine light on. The aeroforce cannot read the code but, when it was on the dyno the tuner told me it was a B2S1 heater circuit failure. Another note to add is these o2 sensors have about 600-800 miles on them and are brand new from Ford. We had a heater circuit failure on this car before and replaced both o2's.

Mods:
2.9 whipple (un-tuned because of the o2's)
72lb injectors
FRPP CJ TB
10% lower
BAP
JLT Intake
Full Stainless works exhaust

I'm convinced its a PCM failure since the problem swapped sides without any reason. Any feedback or run-in's with this kind of problem?

Thanks

 

[Van@RevanRacing]

So as you can see by the thread title I have a 2012 Shelby that I'm working on(gf's car). We had it on the dyno the other day and the Bank 2 Sensor 1 flatlined at 0.00, intermittently it would come back and read A/F for a few minutes then back to nothing.

I went to trouble shoot the problem today and while i was driving it down the highway when they both began reading, shortly after Bank 1 Sensor 1 flatlined. So, the problem switched sides for no apparent reason. I pulled over into a parking lot and continued to watch the aeroforce gauge. While idling the B1S1 would momentarily return with an A/F reading, then turn off again. I drove the car home and the B1S1 would read for about 1-2 minutes at random and when it did the reading was fluctuating wildly from -2 to +4 of the B2S1 sensor.

Also, as a side note every time i start the car it has a check engine light on. The aeroforce cannot read the code but, when it was on the dyno the tuner told me it was a B2S1 heater circuit failure. Another note to add is these o2 sensors have about 600-800 miles on them and are brand new from Ford. We had a heater circuit failure on this car before and replaced both o2's.

Mods:
2.9 whipple (un-tuned because of the o2's)
72lb injectors
FRPP CJ TB
10% lower
BAP
JLT Intake
Full Stainless works exhaust

I'm convinced its a PCM failure since the problem swapped sides without any reason. Any feedback or run-in's with this kind of problem?

Thanks

Full Stainless Works exhaust? Does the car have long tube headers? If so are you using extensions?

 

[wallywagon]

Same story here, and Van: I have longtubes without extenstions. Do you think that is what is causing my issue?

 

[Van@RevanRacing]

Same story here, and Van: I have longtubes without extenstions. Do you think that is what is causing my issue?

I've had a number of customers with this problem and it was either the O2 wasn't long enough or the extensions didn't work.

Here's the solution that has worked for my other customers.

Ford 2011-2013 Longer Oxygen Sensors for Long Tube Headers - Revan Racing, Inc.

Van

 

[JeremyAlan]

Van,

I had a shop install them but i will check on them.

Thanks,
Jeremy

 

[Van@RevanRacing]

Van,

I had a shop install them but i will check on them.

Thanks,
Jeremy

The extensions I have listed will probably cure the issue.

Van

 

[Seer]

Yep, I had the same issue, Van and i figured, the longer oxygen sensors, which are part # DY-1184, from the Ford Raptor would work.

Plugged them in and they worked. Plenty of wiring for this, must do mod when doing long tubes on a 2011+ GT500. Dont trust extensions, and do not cut/lengthen the sensor. This is the best method to solve this issue.

 

[jenkins_1120]

I had a problem like this with mine all we did was took the plastic piece out that was in the middle of the connector. All we used was a pocket screw driver and mini needle nose pliers. Don't know if its the same in your situation but it might help.

 

[JeremyAlan]

So i got under the car and the harness' looked to be fine and not under any stress or be stretched. one of the pins seemed a little pushed in on the car side of the harness on Bank 2's plug. fixed that and swapped sensors and the problem seemed to have followed the sensor from bank 1 to bank 2. So when i put in another sensor the car wouldnt read at all. Then i replaced both sides with the old sensors that came on the car stock and we are back to square one.

B1S1 is dead and comes on momentarily before shutting off again.

I'm convinced its the PCM

 

[Van@RevanRacing]

One constant since the long tubes.

O2 extensions. Eliminate the extensions. If that doesn't fix it. Then I would say PCM. Extensions have caused this issue more times than I can count.

Just trying to help and I've done this a few times.

Van