Check Engine Light: Lean Fuel Condition

[Riceye]

Hi neighbor.

Checking this out, the xxxx161 Denso is for a non-Cali manual trans. Looks like two xxxx162 sensors are what you need if your rig is a non-Cali with an auto trans.

I have the best success here in Wisconsin carefully cutting off the nuts with a Dremel with a cutoff wheel, chasing the threads with an appropriate m8x1.25 die, and re-installing the new sensor and gasket with fresh m8x1.25 copper clad nuts. Don't even bother trying to loosen with a wrench as breaking a stud is a setup for way more work and expense.

 

[19963.4lsr5]

Barillo, O2 sensors hardly ever code for old and worn out. Usually they only code for the heater circuit or when the heater circuit shorts to the sensor side and you get the code for higher than expected sensor feedback-threshold-......on the rare occasion one may get the slow response code.

Other than testing the heater circuit as per the FSM I am really skeptical on testing anything on the sensor side.


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[Riceye]

Barillo, O2 sensors hardly ever code for old and worn out. Usually they only code for the heater circuit or when the heater circuit shorts to the sensor side and you get the code for higher than expected sensor feedback-threshold-......on the rare occasion one may get the slow response code.

Other than testing the heater circuit as per the FSM I am really skeptical on testing anything on the sensor side.


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The other issue that arises, particularly in the rust belt, is gasket failure. Not only does exhaust leak out, but oxygen-rich fresh air will leak into the exhaust stream messing up the sensor's reading. On non-Cali exhausts the front sensor controls lambda, the second one measures results of the first and health of the cat.

 

[19963.4lsr5]

The other issue that arises, particularly in the rust belt, is gasket failure. Not only does exhaust leak out, but oxygen-rich fresh air will leak into the exhaust stream messing up the sensor's reading. On non-Cali exhausts the front sensor controls lambda, the second one measures results of the first and health of the cat.

You are on point. I mentioned many times that exhaust leaks near the front O2 sensor will really mess things up due to what’s called “Reversion” where the exhaust pulses will actually suck fresh air into the exhaust stream and mess up both of the O2 sensor readings.

A friend of mine with a TACO truck with the 3.4 replaced his O2 sensor and didn’t put on the gasket and his lean code came back. I shamed him into actually installing the gasket and his code and check engine light went away on his next drive to work.


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[brillo_76]

Barillo, O2 sensors hardly ever code for old and worn out. Usually they only code for the heater circuit or when the heater circuit shorts to the sensor side and you get the code for higher than expected sensor feedback-threshold-......on the rare occasion one may get the slow response code.

Other than testing the heater circuit as per the FSM I am really skeptical on testing anything on the sensor side.


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Well mine did each time they failed the meter test. Gaskets were not leaking and when I replaced them my code was gone


When the meter tests fail the sensor I replace. Heater circuit goes. Thus kicking on the CEL

Yes we check the heater circuit of the O2 sensor as that's the section that fails

So when 1/2 the sensor is dead it's dead and needs to be replaced.

Well that's what I do.

Why would you not replace it?

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[WrenchTech]

Since I'm already going to be replacing my oxygen sensors, I will probably just apply some heat to the nuts with a small welding tip on my oxyacetylene outfit. If I get them glowing red, I should be able to spin them off with my bare hands (after they cool of course). Well that might be overly optimistic, but certainly a pliers would do the trick.

 

[brillo_76]

Since I'm already going to be replacing my oxygen sensors, I will probably just apply some heat to the nuts with a small welding tip on my oxyacetylene outfit. If I get them glowing red, I should be able to spin them off with my bare hands (after they cool of course). Well that might be overly optimistic, but certainly a pliers would do the trick.

I could be wrong. But I think those are single use nuts on O2 sensors like the 3 nuts on the header flange.


Anything exhaust bolts and nuts it's always best to heat then remove. Great plan along as you are happy with it.

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