I have a 97 Civic HX with the CVT transmission. It is completely stock and I've been getting about 30mpg's with mostly city driving. I was just wondering if this is about average or are you guys getting better than that?

Also, I have another question. I have debated on putting a header on this car but I know it will throw a CEL for not having a cat. Is there a way around this or will not having a cat not really hurt anything?

 

I got about that or less with my '00 cvt. I hated the automatic though and did a b16 swap.

But yes you will absolutely throw a cel for not having your cat.

 

Oh I know i'll throw a code, but will it hurt anything?

 

If you must pass an emissions inspection in your state, then not having a cat may be a problem. Otherwise, the only negative impact would be increased exhaust pollution.

I think 30 mpg is low for an HX. When was your last basic tune up?

 

There's ways around it...

Re-do your exhaust to include a cat & then re-do wiring on your secondary o2 sensor

That would be the right way to do it..


but if you run without your cat it will affect your mileage and pollute a bit more yeah.

 

30 mpg isnt too bad with mostly city driving.. i get on average 32-35 mpg depending on the temp, but mines a 96 ex w/ a LS swap.. manual.

 

Your mileage is very good. But the HX model was designed specifically with fuel economy in mind. It has a highly efficient engine and transmission and should exceed the gas mileage that you are seeing.

 

id expect high 30's on highway and low 30's around city with a manual, with the cvt maybe a bit less... so sounds like your on mark. time for a 5 speed swap?

 

i believe you on the hx, im pretty happy with my mpg/ i commute a min. of 40 miles each way to work on the highway.. so all i do is cruise. ive gotten as high as 38 mpg twice. but never under 30 mpg with all kinds of driving..

 

Now im prob going to sound like an idiot but honda did a cvt in 97??

 

i average 38 mpg city/highway

 

With A/C? What set up?

 

Last tune up was probably 6k miles ago. It also has new primary O2 sensor and I've taken all the egr stuff off and cleaned it because it was extremely dirty.

 

I'd actually love to do a 5spd swap just not sure how hard it actually is.

 

Unfortunately, the 5 speed swap is kind of a PITA on the HX CVT cars because of the STUPID passenger side mount. You can do it but you'll need to do some fab work to make it happen.

My 96 HX got a best of 39 mpg on the highway. Around town, it was mid 30's. I'm a fairly big guy (around 300) so that actually hurt. My friend I bought the car from was only about 120 lbs and he got over 40 on a regular basis. He learned how to hypermile the car pretty well and I think he got mid-upper 40's on a few tanks of gas.

On your converter, you can use the EX exhaust manifold and a standard cat from the same. Just extend your "rear" O2 wire from the front of the engine to the back and you are set. I've done this on a few cars that had the cat integrated to the manifold.

 

Do they make O2 extensions or can you just cut and splice in some wires?

 

I have a 98 5 speed HX. I don't worry about how my mpg is because It's always great. I drive fast and still get good mpg. I removed my cat and my O2 sensors because I live in California, and I don't want to have to replace them if they stop working. I've had to replace the cat once already, and I was lucky to find one for $150 used. So I will only put them on to smog my car, and then I'll take them off. Even with a CEL, I still get good gas mileage. I'd say that if you have no cat, remove your oxygen sensors altogether, so as not to throw off the ECU with invalid readings.

 

I thought if you removed the primary O2 that it could hurt your motor?

 

This is what I've noticed. I was running it with the primary O2 sensor, which was a bad O2 sensor, and without the second (wideband). I was getting crappy mpg. After removing the primary as well, my mpg seemed to return to normal.

 

You can buy an extension harness (I think casper's has them), you can build one, or you can just extend your wires and solder and heat shrink them. I do not recommend bypassing the primary O2 sensor as that helps your gas mileage. Unless the HX is different than any other Honda, it will also throw O2 sensor codes for whatever sensor is malfuntioning or not present.

 

okey! im a owner of a 1997 honda civic HX 5 spd. and one thing you should know about the HX (automatic with cvt or 5spd) is that this engine/module is different from the rest of the civic line. this engine(d16y5) included VTECH-E, notice the "E"? this E stands for efficiency!!!(not performance or anything else) which in your case the vtech is used in low rpm instead of high rpm to gain efficiency, so in other words=YOUR CAR IS NOT A RACE CAR!!!115hp and 104 torque will not get u anywhere fast. so save your money in mods. One of many unique things in this car is that a has a 5-wire O2 sensor, meaning that it has a wideband O2 sensor=$$$ in other words. this wideband O2 is what helps the HX get great gas mileage and if u mess around with it u will get the cel. and will get worst gas mileage. having a wideband O2 is rare. the only reason you have this in your car is because honda was looking for a way to improve the vtech system and as an outcome came the vtech-e. as some of you notice, this came at a high price to fix. honda notice that this is and expensive option to have in a affordable car and decited to stop. wideband o2 is now being used for top-end cars and for performance only. so take care of your HX, and just leave it alone. ur lucky to have this car that gives such great mileage.
quickly! can you tell me what other car from the late 90's can give you such great mileage????
yeah i know! its hard!

 

FYI, here are the current ratings for the HX:

5 sp: 30/38
CVT: 29/35

The VX is currently rated 39/50