O2 sensor woes 7.4 B2 S1 and B1 S2

Scupper · Apr 22, 2024

Hey guys, I am trouble shooting a dead O2 sensor on my 98 7.4l. I swapped the original OE one with a bosch one and it is still showing that it is dead on the live data. I am getting bias voltage on B2S1. I verified that I have low resistance between the ECM connector and the O2 sensor connector and all wires ring out with less than .5 ohms of resistance. Are there any issues with using the bosch O2 sensors? Could this possibly be a bad ECM? Starts fine and runs a little rough and you can tell it is running rich. Thanks in advance.

GoToGuy · Apr 22, 2024

If the ECM can't read the mixture, no O2 sensor input, it defaults to set programming mixture. Overly rich.. are you using a scanner to read , monitor O2 feedback? Sensor 1 each side is what feeds mixture input to ECM. Sensor 2 is feedback monitoring cat health for smog emissions.
Me, I use NGK/ NTK O2 sensors, some Bosch stuff is sketchy once in a while.
Can you swap in a good sensor to test , like left to right, see what happens?

Scupper · Apr 23, 2024

GoToGuy said:
If the ECM can't read the mixture, no O2 sensor input, it defaults to set programming mixture. Overly rich.. are you using a scanner to read , monitor O2 feedback? Sensor 1 each side is what feeds mixture input to ECM. Sensor 2 is feedback monitoring cat health for smog emissions.
Me, I use NGK/ NTK O2 sensors, some Bosch stuff is sketchy once in a while.
Can you swap in a good sensor to test , like left to right, see what happens?

I am using my scanner to read. Bank 1 sens 1 works fine, so I am going to see about swapping that sensor over. I was hoping to do that as a last resort as I think it's the original sensor in there and I had a hell of a time getting Bank 2 sens 1 out lol.

Scupper · Jun 28, 2024

Update for all

Put in an OEM sensor and it worked. Bosch is no good.

GoToGuy · Saturday at 12:12 AM

It's a hassle but you got the answer. Good for you. NGK / NTK are a quality brand. I use them on my 91 C1500 stepside, 93 K1500, 95K2500, 98 Tahoe, and 2007 mini Cooper sport.

Road Trip · Saturday at 12:43 AM

GoToGuy said:
It's a hassle but you got the answer. Good for you. NGK / NTK are a quality brand. I use them on my 91 C1500 stepside, 93 K1500, 95K2500, 98 Tahoe, and 2007 mini Cooper sport.

My experience with NGK / NTK is the same as yours. Never been disappointed by them. On the other hand, I've had mixed results with
Bosch O2 sensors. As a matter of fact, way back when I was only using Bosch, I was experiencing difficulty on
my first (Brand H) DD, and after some research bought my first NTK O2 sensor. Problem solved. (So good in fact
that I would be wary of counterfeit jobs from online sources?)

****

@Scupper, thanks for returning to this thread and sharing the fix for the problem you identified. By doing so,
you have made this thread much more valuable to others who are researching similar issues. Well played.

O2 sensor woes 7.4 B2 S1 and B1 S2

Scupper

Newbie

GoToGuy

I'm Awesome

Scupper

Newbie

Scupper

Newbie

GoToGuy

I'm Awesome

Road Trip

Supporting Member

Attachments

Similar threads

Latest posts

Members online

Forum statistics

Share this page