hole in air line bricking my O2 sensors?

[mfaerber]

1998 Taurus Wagon SE, 140k miles

Error Codes:
P0135 - O2 Sensor Heater Circuit (Bank 1 Sensor 1)
P0155 - O2 Sensor Heater Circuit (Bank 2 Sensor 1)
P1131 - P11XX Manufacturer Controlled Fuel and Air Metering (aka mass air flow sensor)

Over the weekend I ultimately had all 5 of my O2 sensors replaced because the mechanic could not figure out what was triggering the two O2 sensor codes (I think he literally forgot about the third code...) I had this done out of state and on the drive back home (150 miles) my check engine light came back on. I had the error codes read again and the same 3 codes popped up again. I then discovered that I had a hole in one of the air lines and was told that that was what was causing the problem with the sensors. I replaced the hose and disconnected the battery. The engine light stayed unlit for about 20 miles but then came back on. Took it to have the errors read again and the same 3 sensors were giving errors again.

Here is my question. Is it REALLY possible that after about 150 miles worth of driving with brand new sensors (minus the mass air flow sensor), for said sensors to go bad as a result of the hole in the air line? I have a second set of sensors ready to be installed (by me this time), but I am not confident that the new ones were ruined by the hole in the line alone. My car is in fine shape all around and has had all of it's appropriate tune-ups, etc.

Thank you in advance, I'm a novice at car repair, but I'm learning.

[tripletdaddy]

Specifically what air line had the hole? Have you replaced the MAF sensor? The table of codes I have indicates a P1131 is "upstream oxygen sensor for bank 1 is staying lean," a condition consistent with too much unmetered air entering the engine. Not knowing more about what's going on and been done, I wouldn't replace the MAF yet. I'd be looking for a vacuum leak, hissing, cracked hoses and boots. I'm not aware of a problem from O2s with lean conditions, but have heard plenty say too rich for too long will ruin or plug them, though some have had success cleaning them. Maybe someone like Rod will set me straight on this, but I haven't heard of having five O2s, just up to four, on cars.

[mfaerber]

Thank you (exhausted?) tripletdaddy.

I'm trying to find a diagram that lables the lines so I can tell you...

I have not replaced the MAF sensor yet. There is another line that is slightly cracked on the ends, I'll replace that after work today because I have some hose left over. I'm also going to look into cleaning the sensors, know of any good tricks?

[mfaerber]

BY THE WAY

My taurus is a V6 3.0L DOHC

[mfaerber]

and I've been told that the air is too rich, never heard "lean"

and I recently got new spark plugs

[shorod]

Originally Posted by tripletdaddy

Maybe someone like Rod will set me straight on this, but I haven't heard of having five O2s, just up to four, on cars.

No need to set you straight, an OBD-II car will have either 3 or 4 O2 sensors, but not five.

I also agree that the codes would seem to indicate that there is unmetered air entering the system. Since it is unmetered air, that would indicate the air leak is post-MAF sensor. I would not suggest replacing the MAF at this point, but rather closely inspecting all vacuum hoses. I don't think intake manifold gaskets are generally an issue with the DOHC, but would be worth checking as well. The "throttle body cleaner trick" would be helpful for that one.

-Rod

[tripletdaddy]

As a matter of fact, yes, all the time. I have three 7.5 year old BOYS!?! They are a force to be reckoned with. Thanks for noticing.

Rich and lean refers to the amount of fuel not air, which would be consistent with a lean condition and suspected vacuum hose leaks. Sure, you could say things in terms of too much or too little air, but be sure everyone will know that's what you mean.

Just for clarity, Rod, do you mean he should use the tb cleaner trick for leak detection? And, would it be worth cleaning the MAF for this problem, or is it not likely the cause?

[shorod]

Yep, I mean to use the TB cleaner to check for a leak. One could also use carb and choke cleaner, propane, etc. Just be very aware of what's hot under the engine since these sprays/gases are very flammable. Personally I prefer to use the sense of hearing to try to find the vacuum leaks rather than flammable liquids, but the liquids are quite effective.

It never hurts to carefully clean the MAF sensor, but since this code is for unmetered air entering the engine, I would expect the leak to be after the MAF. I suppose though if the MAF is really dirty and therefore not registering all the air accurately that is flowing through it, it may detect a lean condition as unmetered air. What I usually experience with a dirty MAF is poor fuel economy which would be consistent with a rich condition rather than lean.

-Rod

[mfaerber]

Oh snap, I forgot I posted on this forum... How about an update?

I have not resolved my problems yet, but I need to soon, here is what I've been up to:

I replaced another hose that did not look great. I had my girlfriend plug up the exhaust pipes while I listed for hissing, but did not hear anything obvious (it would have had to be REALLY obvious for me to notice it over the roar of the engine, me thinks...). I sprayed what I thought I could spray with WD40 to see if if any would get sucked into the engine and cause it to sputter: nope. I bought a MAF cleaner in a spray can, and cleaned the MAF sensor, though I must say that it looked fine to begin with, everything looked clean and dry (though I wiped everything down with a dry cloth, without touching the sensor of course). I hosed down everything under the hood, battery corrosion had gotten on a few things. I unplugged the batter for a while so that the engine light turned off, but it came on again the next day. I bought a really neat scan tool (LINK) which does a bunch of things, I'll post the kind of summary data that it collected below, but I also had it do a live record under city and highway conditions (it's a LOT of data). Next I'm going to clear the codes with the scan tool and try everything again.

• Control Module
• $10 SAE J1850 PWM
• Vehicle Info.
• Not Supported Or Sto-red No Data.
• Since DTCs Cleared
• MIL Status ON
• Misfire Monitor OK
• Fuel System Mon OK
• Comp. Component OK
• Catalyst Mon INC
• Htd Catalyst N/A
• Evap System Mon INC
• Sec Air System N/A
• A/C Refrig Mon N/A
• Oxygen Sens Mon OK
• Oxygen Sens Htr OK
• EGR System OK
• Stored Codes
• P0155 O2 Sensor Heater Circuit Bank 2 Sensor 1
• P1131 Lack Of HO2S11 Switch - Sens Indicates Lean
• Pending Codes
• No pending codes are stored in the module!
• View Freeze Frame
• DTCFRZF P1131
• FUELSYS1 CL_Fault
• FUELSYS2 N/A
• ETC(°C) 181
• LONGFT1(%) 0.0
• SHRTFT2(%) -6.3
• LONGFT2(%) 0.0
• RPM(/min) 1834
• VSS(km/h) 17
• O2 Monitor Test
• O2 Bank1 Sensor1
• Not Supported Or Sto-red No Data.
• O2 Bank1 Sensor2
• Not Supported Or Sto-red No Data.
• O2 Bank2 Sensor1
• Not Supported Or Sto-red No Data.
• O2 Bank2 Sensor2
• Not Supported Or Sto-red No Data.
• On-Board Mon. Test
• Not Supported Or Sto-red No Data.

I'm going to search for a forum that will help me analyze the rest of the data... I think it's going above and beyond for here...

One test I have not yet done, using the scan tool, is a a component test that commands the vehicle's on-board computer to perform a leak test of the EVAP system. Which sounds great, but it warns that I need to first figure out how to stop the test once it has started... Strange... So I'm researching that now as well.

[shorod]

So when the code P1131 was set, you were going slow, the engine was pretty much at temp, but interestingly the long term fuel trims were at 0 (which is good, but somewhat unusual) yet the short term fuel trim was at -6.3%. That would indicate that the PCM was attempting to lean out the air/fuel ratio at the same time the bank 1, sensor 1 sensor was reporting a lean condition. Since the PCM was trying to send the mixture lean, that would seem to indicate that the problem may not be a vacuum leak.... I need to think about this one a bit.... I guess it's time to go wash the car.

-Rod

[mfaerber]

Thanks shorod, you're the best!

Keep in mind that the car runs really great, everything is tuned up, oiled up, and my MPG is relatively good.

If it helps, here is a link to a Word document that has the results of real-time data tests that the scanner performed. One test was done in town, and the other was done on the highway: http://rapidshare.com/files/13442611...anner.doc.html

[rhandwor]

I would use a wiring diagram and ohm the wires from the computer to the O2 sensors. I have had numerous wiring problems on Fords as I think you are getting to many codes.
Can you borrow a scope to look at how the plugs are firing. Every couple of months I used to get Saturns in the garage from a Parts store with a dozen codes and all it was was the harness Saturn used to fire the plugs.
Did you ever replace any wire to the sensors that was shielded and use normal wire this will really mess up a sensor.
Look at the ground strap for the computer and make sure the shielding ground wire is attached.
You can ohm all plug wires intermittant firing will set codes.
Cracks in the exhaust system will cause problems.
Make sure your timing is set correctly as this will cause numerous codes.
Normally replacing sensors with no change means you have other problems.

[way2old]

On your freeze frame data, it shows the ECT as being ETC(°C) 181 I am not real swift on the conversion, but isn't that rather high? 181 would be closer to normal for a farenheight reading. If so, that could be your problem. The ensuing codes could be a result of the PCM trying to correct for a faulty ECT.

[shorod]

Originally Posted by way2old

On your freeze frame data, it shows the ECT as being ETC(°C) 181 I am not real swift on the conversion, but isn't that rather high? 181 would be closer to normal for a farenheight reading. If so, that could be your problem. The ensuing codes could be a result of the PCM trying to correct for a faulty ECT.

Good catch! Way to pay attention to details! I saw the 181 and filled in the units in my mind. That would equate to about 358 degrees F.

-Rod

[mfaerber]

Great going!

I'm learning about the ECT sensor now ( http://www.autozone.com/shopping/rep...00c1528003aabf ).

Seeing as this car has been to the mechanic several times in the past couple months, if the engine was REALLY running 357F (that isn't even possible... right?), then that would have caught... I would think.

So HOPEFULLY it is just a bad sensor.