Not getting impressive fuel economy with the Civic

[DUBPL8]

Hi guys,

I have been experiencing less-than-stellar fuel economy in my Civic VX as of late.

When I first bought it in Feb of 06, I used to get at least 38-40; now I'm lucky to get even 32mpg.

Here's what I've done so far since owning it:

Spark plugs
Spark plug wires
O2 Sensor
Timing belt and water pump
A/C and alternator belt
Fuel filter
Distributor cap and rotor
Proper tire pressure on all 4 tires
Oil pan gasket and valve cover gasket replacement
Adjusted valves
New EGR valve
Adjusted timing to proper setting
Cleaned IACV and FITV
New catalyctic converter

One thing I haven't done yet is fuel system cleaning.

What the hell gives? It barely lasts me 300 miles on a full tank.

Also, the car is bone stock, with the original D15Z1 intact.

Thanks.

[kwtorbe]

Is it running rough? Fast idle? Symptoms? Are you driving differently? I can only suggest some new/used 190cc VX injectors like you thought or maybe timing....

Did the mileage get worse after any of the service was done?

Good Luck!
Kent

[thisisntjared]

yea we need more symptoms. not just the problem. it could be the new cat.... but with such a drop, there has to be more than one problem

[DUBPL8]

Haven't had any symptoms, other than usual V-TEC-e kick at 2100rpm's or so.

I usually drive it a bit hard just to keep up with traffic, but I even drove it normal a couple of times and it has yielded no improvement in fuel economy.

Would fuel system cleaning at a shop help? I'm frustrated because I bought this car with the assumption that it would net me at 40mpg or higher.

[mrmad]

I'd jack the car up and see if you have any brake drag.

[DUBPL8]

Originally Posted by mrmad

I'd jack the car up and see if you have any brake drag.

Brake drag? Elaborate.

[VetteOwner]

its where your front calipers and or wheel cylynders act like your constantly pressing the brake as you drive. go for maybe a 5 minute drive at highway speeds (or close to it) without touching your brakes. pull off the highway on a side street or somehting, get out and touch the rim itself and lugnuts (take off the hubcaps prior) if they burn you that wheels brakes are dragging. if its somewhat warm its normal, but if its liek touching a frying pan its dragging.

it can becaused by several things, siezed calipers (rusted) or if you hit anyhting to cause a crease in a brake line it will allow you to push fluid thru the crease but will have a hard time comming back thru to release that brake. also deteriating rubber caliper brake lines can do this.

[thisisntjared]

ooo maybe if you hit something it couldve whacked out your alignment...

anyway what kind of driving do you do?

[jadziasman]

My guess is a bad cylinder. I experienced a very loud detonation event going up hill at 75 mph with the VX overloaded with some of my stuff when I moved to Michigan (I know, that was really dumb!!). It was never the same after. Its mpg dropped from 45 to 35 once this happened. You might want to do a compression test on all 4 cylinders.

[VetteOwner]

^^^ you may have burnt a vale or somehting^^^^^^

but yea a compression check is like a MRI for us. it tells ups whats going on internally in the engine with a very easy/simple test.