scrid

Well yesterday I started my truck and noticed the CEL was on.
( 93' 4runner 3.0 )
The truck seemed to be running fine though. I pulled into a gas station to fill up and decided to check logged codes while waiting. The ECU had logged a single code 26.
This is the first code I have experianced with the truck since installing the rebuilt engine in 95'.
The service manual describes this as a rich fuel condition as you all probaly know, and lists a plethera of potential problems.
I have never changed the O2 sensor on this truck and was was wondering what everyone elses opinion on attacking this might be.
I personally thought maybe it was fluke and could clear the code and see if it repeats in the next couple weeks before looking deeper.
Or just replace the O2 sensor (since it's never been done since I have owned the truck) test the cold start injector, water temp sensor, and then clear the ECU and wait.
Any thoughts?

Targetnut

warm your engine up and check the voltage at terminals Oxy1 and E1 in your diagnostic connector under the hood.

run the engine at about 2000 RPM. The voltage should switch back and forth between 0.2V and 0.8V about 8 or more times in ten seconds.

If that is OK check the voltage between Vf and E1 Ideally it should be about 2.5V. less than that indicates the O2 sensor indicates a rich condition and the ecm is reducing the amount of fuel injected. The code would set when the Vf is at 0V and the O2 sensor is staying predominantly above 0.45V

scrid

Thanks for the input, will do and post back results.