O2 sensors on a 95 code W

[dagwoods4x4]

I am trying to find out how many 02 sensors are on my late 95 code w V-6.
The engine data tag under the hood says OBDI, but the test plug under the dash is OBDII. I keep getting P1133 codes from the computer and really bad gas mileage. The chevy dealer says the truck is OBDI and has only 1 o2 sensor, but the readout from the computer says sensor 1,bank 1. Where and how many sensors are there. I know about the one after the converter, are there more than that???????????

[Sparky2263]

It could have 1, or, it could have 3.If you don't have an O2 sensor right behind the converter, then you only have 1. The 1133 indicates that the O2 sensor is not switching (dead). If it's the original sensor you can just about guarantee it's bad.

Here's the tech side of it straight from GM;

CIRCUIT DESCRIPTION
The Vehicle Control Module-A (VCM-A) supplies a voltage of approximately 0.45 volt (450 mV) between VCM-A pins "BL21" and "BL7".

NOTE: If this voltage is measured using a 10 megohm digital voltmeter, the voltage may read as low as 0.32 volt. The Heated Oxygen Sensor (HO2S) varies the voltage within a range of about 1 volt (1000 mV) if the exhaust is rich to as low as 0.10 volt (100 mV) if the exhaust is lean.

When the HO2S temperature is below 360°C (600°F), the sensor will not produce any voltage and will behave like an open circuit. This will result in "Open Loop" operation.

The HO2S heater provides for faster sensor warm-up which allows the sensor to become active in a shorter period of time and remain active during long extended idle. DTC P1133 determines if the HO2S is functioning properly by monitoring the number of L/R and R/L switches.

DTC P1133 WILL SET WHEN

No fuel trim DTCs.
No Throttle Position (TP) sensor DTCs.
No Evaporative Emissions (EVAP) System DTCs.
No Intake Air Temperature (IAT) sensor DTCs.
No Manifold Absolute Pressure (MAP) DTCs.
No Exhaust Gas Recirculation (EGR) DTCs.
No Engine Coolant Temperature (ECT) sensor DTCs.
DTC P0135 (oxygen heater) not set.
"Closed Loop."
Oxygen voltage between 0.300 and 0.600V.
Throttle position is between 10% and 20%.
L/R switches is less than 30.
R/L switches is less than 30.
ACTION TAKEN (VCM-A WILL DEFAULT TO)
The VCM-A will turn "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon) after the second test failure.

DTC P1133 WILL CLEAR WHEN
The VCM-A will turn the MIL "OFF" after three consecutive trips without a fault condition present. A history DTC will be cleared if no fault conditions have been detected for forty warm-up cycles [coolant temperature has risen 22°C (40°F) from start-up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle] or the Tech 1 clearing feature has been used.

http://www.s10planet.com/forum/attachment.php?attachmentid=1809&stc=1

[dagwoods4x4]

It does have an o2 sensor just behind but still in the converter . I have spoken to A GM service rep and he thinks i,m crazy by telling him my truck is OBDII and being a 95.
I have been unable to locate the other sensors, have any ideas where they are at????

[Sparky2263]

Here's a pic.

http://www.s10planet.com/forum/attachment.php?attachmentid=1810&stc=1

[dagwoods4x4]

thanks for all of your help, now to get them out of the pipes without breaking something