Mechanics

CHEVY OXYGEN SENSOR BAD?

2000 Chevrolet S-10

Engine Performance problem
2000 Chevy S-10 4 cyl Two Wheel Drive Automatic 50000 miles

My Chevrolet S10 is burning more fuel now. My OBDII scanner gives the following readings for the oxygen sensors:

O2 B1 S1 shows fluctuations from.1 to.7mv

O2 B1 S2 shows a constant.7mv

This is in Closed Loop after warm up.

The O2 and CAT monitors show that they have not completed their monitoring.

I appreciate your help.
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Bushpilotchuck
October 31, 2008.



Your 02 readings look OK, check/clean the MAF, it controls injector pulse width.

Merlin2021
Oct 31, 2008.
No MAF on this vehicle. Checked the MAP sensor and it seems to react slowly. Thinking it might be contaminated. Can it be cleaned?

Tiny
Bushpilotchuck
Nov 4, 2008.
Ok here's the sensor range charts, you need to check them starting with the 02.
ARTICLE BEGINNING INTRODUCTION Sensor operating range information can help determine if a sensor is out of calibration. An out-of- calibration sensor may not set a trouble code, but it will cause driveability problems. DFT (1), ECT (2) & IAT (3) SENSOR RESISTANCE (EXCEPT TRACKER)
NOTE: Unless stated otherwise in test procedure, perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance. Temperature - °F ( °C) (4) Ohms 212 (100) 177 194 (90) 241 176 (80) 332 158 (70) 467 140 (60) 667 122 (50) 973 113 (45) 1188 104 (40) 1459 95 (35) 1802 86 (30) 2238 77 (25) 2796 68 (20) 3520 59 (15) 4450 50 (10) 5670 41 (5) 7280 32 (0) 9420 23 (-5) 12,300 14 (-10) 16,180 5 (-15) 21,450 -4 (-20) 28,680 -22 (-30) 52,700 -40 (-40) 100,700 (1) Diesel Fuel Temperature (DFT) sensor. (2) Engine Coolant Temperature (ECT) sensor. (3) Intake Air Temperature (IAT) sensor. (4) Measure resistance across sensor terminals. Page 1 of 3 SENSOR RANGE CHARTS -2000 Chevrolet S10 Pickup
MAP SENSOR VOLTAGE OXYGEN SENSOR VOLTAGE THROTTLE POSITION SENSOR VOLTAGE
Throttle Position (1) Volts At Idle 1.0-1.5 Wide Open Throttle 4.0-4.9 (1) Measured at sensor, or as seen on scan tool. Ensure sensor output changes instantly when intake manifold vacuum is applied and released. Condition (1) Volts Lean.1 Rich.9 (1) Measure voltage between oxygen sensor ground and signal terminals at PCM/VCM. Throttle Position (1) Volts At Idle 0.6 Wide Open Throttle Greater Than 4.0 (1) Measured at sensor, or as seen on scan tool.

Merlin2021
Nov 6, 2008.