I Went to the store the other day, and as i was pulling out of the parking lot i noticed my engine RPM's floating up and down. Next, i noticed as i pulled up to the stop light the motor wanted to die, and got worse with the AC turned on. When i turned the AC off, it seemed to make the motor smooth out. So i drove the 2 miles home with my AC turned off, but right before i got home, the Check Engine light came on, and stayed on.
Upon getting home i hooked up my Snap On MT2500 code scanner to see if any codes had been set. Only one code came up, a code 26, i then check a live stream of data with my motor running. First thing i noticed in closed loop, only one of my O2 sensors was switching from lean to rich, the other one just keep reading rich all the time, a code 26 is for a motor that is running rich. I then checked the sensor voltage, the one sensor that was switching between lean, and rich was reading 2.5 volts. The other sensor that was reading just rich, was reading 0 volts.
I then checked my scanner for information on a code 26, from what i read it looked like the problem i was having was coming from a bad O2 sensor. I then checked to see when my O2 sensors had last been changed, as it turned out, they were last changed 98000 miles ago. Since they had so many miles on them, i though it was a good idea to change them, then retest the operation of the O2 sensors.
So i ordered up the factory Toyota O2 sensor kit, that kit (89465-60110) comes with 2 new sensors, along with 2 new gaskets, plus 4 new sensor nuts. I ordered up the kit along with 2 new exhaust gaskets for the head pipe, 4 new head pipe lock nuts, plus 2 new exhaust gaskets for the Cat Y pipe. As it turned out, the Factory Toyota O2 sensor kit was less money then 2 aftermarket Denso O2 sensors from Rock Auto.
Upon retest of my new O2 sensors in closed loop they both were now switching between lean and rich and the one was reading 2.5 volts and the other 3.75 volts. Please note that these voltage readings are in the normal operating range of 1.25 to 3.75 volts.
I read alot of threads were Mud members were able to replace their o2 sensors without dropping their exhaust system. In my case i had no such luck, even though my truck has no rust at all, whatever type of metal Toyota made those 4, O2 sensor lock nuts out of, they were completely eaten away by corrosion, to the point were they had no flats left on the nuts. After installing 2 new sensors, and clearing the code, I'm happy to report my trucks back to running normal. Below is a link to Toyota's special service campaign for O2 sensor replacement that lists all the part numbers, nut and bolt torque amounts, along with a step by step guide on how to do this job
http://www.risingsun4x4club.org/uploads/Snowrun/1994 fzj80/1994 Repair manual/Service bulletin/T-CP-SO2-0162-W.pdf
Upon getting home i hooked up my Snap On MT2500 code scanner to see if any codes had been set. Only one code came up, a code 26, i then check a live stream of data with my motor running. First thing i noticed in closed loop, only one of my O2 sensors was switching from lean to rich, the other one just keep reading rich all the time, a code 26 is for a motor that is running rich. I then checked the sensor voltage, the one sensor that was switching between lean, and rich was reading 2.5 volts. The other sensor that was reading just rich, was reading 0 volts.
I then checked my scanner for information on a code 26, from what i read it looked like the problem i was having was coming from a bad O2 sensor. I then checked to see when my O2 sensors had last been changed, as it turned out, they were last changed 98000 miles ago. Since they had so many miles on them, i though it was a good idea to change them, then retest the operation of the O2 sensors.
So i ordered up the factory Toyota O2 sensor kit, that kit (89465-60110) comes with 2 new sensors, along with 2 new gaskets, plus 4 new sensor nuts. I ordered up the kit along with 2 new exhaust gaskets for the head pipe, 4 new head pipe lock nuts, plus 2 new exhaust gaskets for the Cat Y pipe. As it turned out, the Factory Toyota O2 sensor kit was less money then 2 aftermarket Denso O2 sensors from Rock Auto.
Upon retest of my new O2 sensors in closed loop they both were now switching between lean and rich and the one was reading 2.5 volts and the other 3.75 volts. Please note that these voltage readings are in the normal operating range of 1.25 to 3.75 volts.
I read alot of threads were Mud members were able to replace their o2 sensors without dropping their exhaust system. In my case i had no such luck, even though my truck has no rust at all, whatever type of metal Toyota made those 4, O2 sensor lock nuts out of, they were completely eaten away by corrosion, to the point were they had no flats left on the nuts. After installing 2 new sensors, and clearing the code, I'm happy to report my trucks back to running normal. Below is a link to Toyota's special service campaign for O2 sensor replacement that lists all the part numbers, nut and bolt torque amounts, along with a step by step guide on how to do this job
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