I need some help on a Check Engine Light - 02 Sensor problem. The light only comes on when I drive over 65mph. I checked the OBD and the light code is the 02 Sensor. I checked with Honda and a replacement sensor was about $200! So I went to Advance Auto and bought a Bosch univeral for about $20. I installed the new sensor and cleared the ECU, but the Check Engine light still comes on. Is there something that I am missing? Does it take awhile for the ECU to clear the code (100 miles or something)? Did I buy the wrong 02 Sensor? Do I need to replace something in addition to the 02 Sensor?

 

hmm thats kinda funny it did that to me too and i have the bosch one too but when i put it on it went off right way.. dose your car do anything eles funny.. becouse when my 02 went on the car could just not move it would start to slow down and bog really bad

 

How did u clear the ECU? U must either unhook the battery, the ECU fuse, or the ECU itself for about 10 minutes... And how many wires did this universal o2 sensor have on it? The stock one uses only one wire...

 

We need more information, specifically what OBD and computer you are running (or at least the trim level of the car if it is unmodified.)

 

It is a 1990 Civic DX (1.5l) 5MT with 180,000 miles. I believe this model has the OBD-1, but I am not certain. When I replaced the 02 sensor, I only pulled the ECU fuse for about 30 seconds. Does it need to be removed for a longer time periord (10min...30min)?

The car seems to run good. The Honda dealership said that the first cylinder only has 90% compression, but other than that, it does not seem to have any engine troubles.

The Bosch replacement sensor has only one wire and I followed the basic directions.

Any suggestions?

 

10 seconds.. not minutes.

 

If the car is stock, you have an OBD-0 emissions (computer) system. The one-wire non-heated O2 is normal.

First, return the new O2 sensor and try another. From there, test the O2 sensor curcuit for shorts or opens.

 

Okay, so I took the new O2 sensor off today and found it to be totally black with a charcoal-type residue. I took the part to the auto parts store and the technician said that I have a bigger problem than the O2 sensor. He said that the engine is running too rich and the O2 sensor should be a light gray color instead of black.

I checked the service manual and it says to check the fuel pressure regulator but this requires a gauge which runs about $40. The part is only $60! Does it sound logical that the fuel pressure regulator is bad? I just checked the fuel economy and it is only getting 27mpg which seems low for a 1.5l engine.

Any suggestions? Is there another way to check the fuel pressure regulator without a gauge? Any advice would be great!

 

27mpg is not too bad.

A brand new O2 sensor with a thick black carbon coating is very bad. They should look clean after 100k+ miles. If yours is crapping up that fast, it will throw the check engine again and will show a problem much greater then O2 failure (even though it is the O2 sensor that is directly failing again.)

 

Ah whatever, the important thing is you unhook it for a reasonable amount of time...

Some say 10 seconds, some 15 seconds, some say 2 minutes, I say 10 just to be on the safe side...