92 Teal VX
 

Hello to all. As you can tell i'm new to this forum. I've been lurking around for about 2 months and I'm surprised at the knowledge and courtesy i've seen on this site. Everyone seems very knowledgeable and eager to help each other out.

I currently own a 92 Honda Civic VX. It has about 175,000 on the odometer. I've owned this car for a about 3 years and had no idea it had so much FE potential. Currently I'm getting about 35 mpg which is good now-a-days but not so good for a VX. I'm eager to learn more and get more FE out of the VX.

Thanks,

915VX

35mpg, get a tune up, if the mpg is not goint up, maybe its your O2 sensor that is gone. Have you any check engine code?

After seeing what other VX's were capable of I replaced the spark plugs, wires, cap, & rotor. The car definitely runs better, alot stronger but the gas mileage is about the same. How could I tell if the 02 sensor is going out? It doesnt hesitate or surge. The power is smooth. Maybe I have a California version of the VX?

The California VX has a 4 wire O2 sensor and does not have lean burn capability. The non-CA model has a 5 wire (wide band) and does have lean burn capability. There are others who are much more knowledgable about O2 sensor issues than I am, so I'll leave it up to them to answer your question about how to tell if the O2 sensor is bad. 35 mpg is definitely not right. I used to regularly get 50+ mpg w/ my former '95 VX, CA model.

My wife's '98 HX's fuel economy has dropped significantly in the last 2 tankfuls without any other symptoms....engine is smooth, plenty of power, etc. The CEL with a bad O2 sensor code came on about 1.5 yrs ago when the engine had 85,000 miles on it. Someone on this forum told me to disconnect the battery to reset the ECU, and if the light did not come back on, I was ok. The CEL has periodically come back on a few times since that first time, but I kept resetting it, and no decrease in FE until now. But the poor FE now is not accompanied by the CEL. A couple of members have suggested that the O2 sensor is probably bad, causing the poor FE.

Pop your hood and look at the emissions label. It will say "this vehicle conforms to US EPA regulations" blah blah blah and if it says "California" after that, then you know you have a California car.

cems70, I responded at length to your post about CEL's on OBD2 vehicles. OBD2 vehicles are quite smart and if they throw a code, it's for a good reason. Resetting the ECU doesn't fix the problem, it simply resets the ECU's diagnostic test. Eventually it will complete the test again and throw the CEL. You need to actually diagnose and fix the problem.

Did you even TRY to figure out what the cel code was???

There is no sticker under the hood. Looks like the hood was repainted and the sticker was removed. I checked the O2 yesterday and it is a 5 wire. The ECU is a P07 L00 so it's a cali version. I guess I need to try to get my hands on a A00 ECU (49 State). Once I get the that ecu swapped out I should have lean burn right? Then I just hope that my o2 is good.

I guess the only other thing i should mention is that from time to time my car throws a CEL. There is no pattern to it. I'd say it happens once every 2 weeks. I took it to a honda certified mechanic and he said it was a code 12. He said it had to do with the egr? He said he checked it out and everything was fine. A couple weeks later I got the CEL again. Not sure where to go from here.

Thanks for the feedback fellas, I appreciate it.

You have to jump the two pin connector on the passenger kick panel and the code will flash via the check engine light. Do you have a service manual?

Yes, I mentioned it in my previous post---> "The CEL with a bad O2 sensor code came on about 1.5 yrs ago when the engine had 85,000 miles on it."

Every periodic CEL since then was also the code for the primary O2 sensor (I jumped the two pin connector on the passenger kick panel to see what code flashed on the check engine light).

Well if you know what the issue is, I don't see the problem. If you're questioning whether or not to spend the money to replace the O2 sensor, then what you can do is use a multimeter on the O2 sensor, keep it in the exhaust and check to see if the voltage moves around. The idea is to make sure the O2 sensor is heated up, so if you don't want to test it in the car, then you can test it with a gas torch and check the voltages. You want the voltages to move around and not stay in the same place because if they do, then your O2 sensor isn't doing its job.

Another thing you could do is try driving around without your O2 sensor and see if your mileage changes at all.