Grounded O2 Question

[Mikey]

I have a constantly occuring code 176 (is or was lean in the front bank). If I had a short in any of the wiring for the o2 sensor, would the short cause the voltage of the signal wire to drop.

I used a tool by Walker Exhaust called the catmaster. It basically tells you the voltage the signal wire is at. My front o2 is at .2 volts with the CEL on even under throttle, while the back o2 sensor is reading .7 volts while the CEL is on.

I have taken the following steps one by one and rechecked codes after each step to determine the cause.

1 Switched O2 sensors from front to rear bank and vice versa

2 Switch the fuel injectors from the front bank to the rear bank and vice versa

3 Replaced the fuel pump, (It had low pressure and excess mileage).

4 Sprayed carb cleaner to check for vaccum leaks

And i still get 176 and a constant CEL, any ideas or thoughts would be great because I'm to the point where I just dont know where to look next.

 

[SHOZ123]

You need to check the wiring going to the O2 sensor or the connections. Doesn't take much resistance to drop the voltage when you are dealing with such low values.

 

[Mikey]

Thanks for the info

 

[Mikey]

Anybody have any tips or suggestions on testing?

 

[rangerj]

Mikey,

How long have the O-2 sensors been in the car? If you are getting a CONSTANT VOLTAGE READING then the O-2 sensors are not switching.

O-2 sensors should be changed at 60k mile intervals. If you are getting a signal, ie a voltage reading, the wiring is usually OK. However, as SHOZ123 has stated, it does not take much resistance to reduce voltage that is low to begin with. Check your connections for any corrosion or looseness. rangerj

 

[Mikey]

The O2 sensors have less than 10,000 miles on them. I recently did a full 60k. I switched the front and rear bank's O2 sensors, with the rear banks sensor in the front bank the only code that came up still indicated a lean condition in the front cylinder bank(176). The suspected bad sensor, that was moved to the rear bank, does not set off any codes now.

I just swapped in a new motor, tansaxle, and subframe and this is the one problem I cannot straighten out. Thanks for continuously responding with suggestions.