Lean code

[bconnaway]

I installed my longtubes a few months ago with resonators. I installed the front O2 sensors, but my rears where both pretty much welded into place so I left them off. I have a tune from PHP to account for my cat delete, but just about a month ago I started to get a code for my bank 2 running lean. I was towing something at the time on my tow tune, so I switched back to the performance tune and cleared the code, but a few days later the code popped up again. Is the fact that I do not have my rear O2s causing this or is it something tune related?

[bconnaway]

Any ideas? Over on F150online, it was suggested that I may have either a vaccum leak or a leak into the headers which is causing a false reading. I had the code pop up again last night for the first time in about a week.

[Jackpine]

The fact that you're getting it on different tunes suggests a mechanical problem like a leak to me too. But I don't have any suggestions about how to find it. I wonder if there'd be any "blowby" that might create a "soot mark" if there's a leak?

Sometimes you can hear a leak "whistle", but you might need a stethoscope to be able to isolate that from other engine noises.

- Jack

[bconnaway]

Originally Posted by JackandJanet

The fact that you're getting it on different tunes suggests a mechanical problem like a leak to me too. But I don't have any suggestions about how to find it. I wonder if there'd be any "blowby" that might create a "soot mark" if there's a leak?

Sometimes you can hear a leak "whistle", but you might need a stethoscope to be able to isolate that from other engine noises.

- Jack

Whenever I let the truck idle, I can hear something sounds like it is rattling (I think that may be the fasteners from the Stage 8 bolts), but nothing like a whistle. So, I cleared the lean code and about a week later it popped up again. But this time it had another one...
P0174: System Too Lean (Bank 2)
P2196: O2 Sensor Signal Biased/Stuck rich - Bank 1/Sensor 1

So, what is going on here? My best guess at this point is an exhaust leak on the gaskets (I had reused the Ford factory ones), causing the system too lean code. Truck tried to compensate and started to actually run rich, causing the driver side O2 to go bad... Just want to get ideas before I go back under and start trying to fix things, not exactly the easiest to change the gasket for the passenger side header.

Also, if it makes a difference, I soldered in my own extensions for the front O2 sensors. I wouldn't say I did a poor job, but it was my first time soldering, so could that possibly be causing these issues?

[Jackpine]

Originally Posted by bconnaway

Whenever I let the truck idle, I can hear something sounds like it is rattling (I think that may be the fasteners from the Stage 8 bolts), but nothing like a whistle. So, I cleared the lean code and about a week later it popped up again. But this time it had another one...
P0174: System Too Lean (Bank 2)
P2196: O2 Sensor Signal Biased/Stuck rich - Bank 1/Sensor 1

So, what is going on here? My best guess at this point is an exhaust leak on the gaskets (I had reused the Ford factory ones), causing the system too lean code. Truck tried to compensate and started to actually run rich, causing the driver side O2 to go bad... Just want to get ideas before I go back under and start trying to fix things, not exactly the easiest to change the gasket for the passenger side header.

Also, if it makes a difference, I soldered in my own extensions for the front O2 sensors. I wouldn't say I did a poor job, but it was my first time soldering, so could that possibly be causing these issues?

First time soldering? Certainly could be the cause of lots of problems. They could arise from having a poor solder connection to heat damage on the sensor itself during the soldering process. (Although since O2 sensors are exposed to great heat in operation, I suspect that is not the problem.)

The "stuck rich" signal from one of the sensors indicates a sensor malfunction. Those sensors are actually fairly complicated devices, and they incorporate a heating element to get them working sooner. Here's a description or the Heated O2 Sensor:

The HO2S detects the presence of oxygen in the exhaust and produces a variable voltage according to the amount of oxygen detected. A high concentration of oxygen (lean air/fuel ratio) in the exhaust produces a voltage signal less than 0.4 volt. A low concentration of oxygen (rich air/fuel ratio) produces a voltage signal greater than 0.6 volt. The HO2S provides feedback to the PCM indicating air/fuel ratio in order to achieve a near stoichiometric air/fuel ratio of 14.7:1 during closed loop engine operation. The HO2S generates a voltage between 0.0 and 1.1 volts.

I really don't have any brilliant ideas about this, but I'd have to suspect a problem with the sensors themselves at this point. Trouble is, they're expensive, so you don't want to replace them if it's not the problem.

Can you tell me exactly what it was that you soldered? Was it "extensions" to the wiring? If so, did you insure you had a solid mechanical connection between the two wires before applying solder and, what did you use to insulate the exposed connection? Solder itself is not really there to conduct electricity - it mostly makes the connection "permanent" and coats the connection to prevent oxidization (corrosion).

- Jack

[bconnaway]

Originally Posted by JackandJanet

First time soldering? Certainly could be the cause of lots of problems. They could arise from having a poor solder connection to heat damage on the sensor itself during the soldering process. (Although since O2 sensors are exposed to great heat in operation, I suspect that is not the problem.)

The "stuck rich" signal from one of the sensors indicates a sensor malfunction. Those sensors are actually fairly complicated devices, and they incorporate a heating element to get them working sooner. Here's a description or the Heated O2 Sensor:

The HO2S detects the presence of oxygen in the exhaust and produces a variable voltage according to the amount of oxygen detected. A high concentration of oxygen (lean air/fuel ratio) in the exhaust produces a voltage signal less than 0.4 volt. A low concentration of oxygen (rich air/fuel ratio) produces a voltage signal greater than 0.6 volt. The HO2S provides feedback to the PCM indicating air/fuel ratio in order to achieve a near stoichiometric air/fuel ratio of 14.7:1 during closed loop engine operation. The HO2S generates a voltage between 0.0 and 1.1 volts.

I really don't have any brilliant ideas about this, but I'd have to suspect a problem with the sensors themselves at this point. Trouble is, they're expensive, so you don't want to replace them if it's not the problem.

Can you tell me exactly what it was that you soldered? Was it "extensions" to the wiring? If so, did you insure you had a solid mechanical connection between the two wires before applying solder and, what did you use to insulate the exposed connection? Solder itself is not really there to conduct electricity - it mostly makes the connection "permanent" and coats the connection to prevent oxidization (corrosion).

- Jack

When I soldered them, this is the process I used:

1. Cut the wiring on the O2 sensor about half way up
2. Strip wire and the wire for a 6" extension
3. Heat the wire from the O2 sensor with the soldering gun
4. Once the wire is hot enough, place a small amount of solder on that wire
5. Heat the wire from the extension and once hot enough, put solder on this wire
6. Put the wires together and heat the solder from each wire until they connect
7. Repeat process for remaining 3 wires
8. Electrical tape the soldered connections
9. Electrical tape the entire extension

I was doing this based on what my roommate had told me to do (he's an electrical engineer), but this process definitely has the solder as the main form of contact between the wires. I could go back and try to re-solder the wires to see if that helps. If not, I may end up having to just buy new O2 sensors and actually buy some commercial extensions. Biggest thing though is I really don't want there to be a different problem, replace these sensors, then have them ruined. Just trying to go through the list of the minor/cheaper fixes before tackling that.