restoring factory economy to honda civic vx
 

i have a 92 civic vx , the fuel economy is about 32.5-37.5 with a 5 to 1 city/highway , i would like to get this average to about 38-40 ala factory specs



since i bought the car last winter have replaced

- new oem fuel pump
- new oem fuel filter
- new braided fuel line
- cleaned and remapped oem fuel injectors
- new oem fuel regulator return valve
- new oem spec ngk spark plugs gaped perfectly
- new ngk coilpack/cables
- new distributor
- new oem timing belt
- new oem water pump
- new temperature sensor
- new ecu
- new oem iacv
- new battery
- new axle back exhaust
- new intake filter
- new driver side axle
- throttle body thoroughly sprayed with throttle body cleaner
- tires 42psi+
- egr "scraped" new gasket

even with all these "refreshments" i can still feel the power cut out or "sputter' for a mili-second when cruising at highway speeds i feel like this maybe directly related to my lack luster economy

the 02 censor looked brand new when i bought it , the only thing i can think of that i havent replaced yet

- egr
-cat converter
-new front brakes and wheel bearings to reduce rolling resistance

if there and any other suggestions for things that i missed to get my fuel economy where i want it that would be much appreciated....

Did you max out the tire pressure yet?

Isn't that just the car going into lean burn? Also, you say you are doing 80% city 20% highway, am I reading that right? If that's the case, then your fuel economy doesn't sound too bad.

I would strongly recommend cleaning the egr valve and passages. Lean burn Hondas tend to clog those up.

yup

did that, new gasket, going to buy a new one from advance auto for $200 anyway

fyi brand new egr from napa here in canada is $550 but only $200 at advance auto in states for the exact same egr....

If you already cleaned it, then its probably fine. It sounds like your car is working just fine and that stumble is just it going into lean burn. I have seen one of our members here discussing this kind of situation before: Someone is just throwing parts at their car to make a "misfire" go away, when it just turned out to be the lean burn transition. Then our member proceeded to enlighten the unfortunate person, problem solved!

Any VX experts on here seeing this? Is this just lean burn?

That's exactly what it feels like with my healthy Insight engine.

And, for what it's worth, now that the weather is getting cold, I'm seeing 45-55mpg city trips, whereas I can get 100+ on the highway in summer. Those numbers sound fine for a VX driven in the city in this season.

That's what I thought, lets see what other lean burners say.

I jelly mode activate.

Definitely sounds like lean burn transition.

Since you seem to like spending money, invest in an AEM Wideband air-to-fuel ratio gauge. They are about 200 new, but can be had for 80-120 used. Install it before the catalytic converter, this will tell you exactly when you are going in and out of lean burn, not to mention if anything ever goes wrong you will see it immediately.

[Edit]: Your economy seems typical. Vancouver is really, really cold isn't it? Anything below 70F (forget what that is in 'C'ommunist units) will start impacting economy very quickly.

[Edit of an edit]: What tires are you running? That can also make a huge difference in economy.

Park on a grade, engine off in neutral. Release the brake and assess how easily it rolls. Listen carefully for scraping or grinding noises.

If you can put it on a lift, give each wheel a spin and count the revolutions for comparison.

Consider whether your front brakes have or should have retractor springs.