Kevin510 Report post Posted September 30, 2012 I was wondering if anyone had changed the O2 sensors just for the sake of trying to get better fuel mileage. I do not have any lights on indicating that I should. I also only have about 50k miles on my 2002 w-22 chassis but the exhaust has a very rich smell which hints at needing to replace them. Thanks Share this post Link to post Share on other sites
dickandlois Report post Posted October 1, 2012 Kevin, You did not mention what engine you have. The O2 sensor voltage range must be correct if you are not seeing a check engine light. It should change the fuel mixture by changing the injector on/off interval in relation to the information from the MAP sensor and the O2 sensor. Dirty injectors can effect combustion efficiency. The unburned fuel smell and blacker tailpipe discharge. If you have access to a OB2 scanner, read the codes and if possible drive the unit with it connected to the OB2. You can then monitor the engine performance and note any abnormalities. The unit should give you any misfires and which cylinders, injector performance, mass-air flow and engine data in general. That will give you a baseline to start from. I would check the air filter, the spark plug condition. You might want to run some injector cleaner through the engine. A gray white buildup on the electrodes will indicate whether you have some oil in the upper portion of the cylinder(s). Large engines will burn some oil and that is not all bad. Rich. Share this post Link to post Share on other sites
Kevin510 Report post Posted October 2, 2012 Sorry, it has the 8.1. I bought some injector cleaner and am going to use it the next time I fill the tank (It was good for up to 80 gallons). I pulled the air filter today and while it was not really dirty, it was old and yellowed so I am going to replace it tomorrow. I will pull some plugs tomorrow and go from there. Share this post Link to post Share on other sites
dickandlois Report post Posted October 2, 2012 Kevin, Just got to read your reply. Getting into fall up North and been working on some windows. When removing the plugs, pulling the wires off the plugs can be difficult. So remove the wire from the plug coil first by lightly twisting it to break it free at that point first. Then remove the wire from the plug. This allows you to add a twisting motion to the plug wire and the plug shield and lessen the chances of damaging a good plug wire. There is a Mylar sleeve inside each shield, brown in color. There is a spring at the bottom of the shields. You may need some real short extensions for the plug socket. Like a 1" in some spots and a 3" most of the time. Put just a little anti-seize on the plug threads before installing, even if you are not replacing them. 18 ft-lb is plenty of torque. Tighten the plug with the wrench to a snug point, then a honest push on the wrench. You might get about a16th. of a turn more. I have always used a 3/8in. socket for the job. Always put some dialectic grease on the inside of the rubber boots before replacing them. The 8.1 L is a good engine, been an issue with the crank and cam sensors on some production runs and it was built for power not economy. Some owners have informed me that they run middle grade fuel in them and the difference is price is offset by better MPG. That is a tough one because we all drive differently and with different road conditions. Rich. Share this post Link to post Share on other sites
