02 problems

[lgarner]

My truck started running bad today(2003 2500hd 6.0l) I did a scan and found 4 dtc's p0131,p0137,p0154,p0157. Also the fuelsys a and fuelsys b maintain a ol fault. could someone take a look at my scan file to see if you see anything wrong?

thanks
larry

[odd boy]

From the mv of the O2, you can tell whether the O2 is malfunction or not. To me, they r and you can resolve the issue by replacing them or by forcing the car to be in OL all the time

[joecar]

Exactly what OB said in post #2... NBO2's look bad... question is: did they both go bad at the same time and why...?

[lgarner]

i was thinking that too. but been looking at my fuel pressure and thought it was low. crusing speed it only gets to 45psi. so i removed the vacum line from the pressure regulater and capped it. seems to run alot better. what you think?

larry

[odd boy]

i got this for you from my e-library:

Testing O2 sensors on the workbench.

Use a high impedance DC voltmeter (A acceptable value is 1,000,000 ohms/volt or more on the DC voltage. Most (if not all) digital voltmeters meet this need. ). Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems.

ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

you can make it sticky guys if you like