Poor gas mileage on bone stock d16z6? Help?

ZenkiS14 · Post by **ZenkiS14** » Tue Feb 22, 2011 7:53 pm

So I have had my bone stock 94 Civic Si for almost 4 or 5 years now. And when I got the vehicle it was getting around 38-420 miles per tank, now Im lucky to get 300.

I have no idea why its getting such poor mileage.

In the past 3000 miles I have changed:

K&N Air filter (in stock air box)
o2 sensor
NGK Spark plugs
new tires at proper pressure
fuel filter
oil and oil filter
fixed exhaust leak

after all of this, its still getting less than 300 miles per tank, (29mpg) typically.

I want that 35-42mpg again! What is causing this problem?

MaSSaCrE · Post by **MaSSaCrE** » Tue Feb 22, 2011 8:09 pm

Have the same problem with my DD, was getting 30-32 now getting about 25 on a good week.

Post by **stolle** » Tue Feb 22, 2011 8:11 pm

maybe a clogged catalytic converter?

tommygun89hb · Post by **tommygun89hb** » Tue Feb 22, 2011 9:49 pm

id you gap your spark plugs????? I think on a z6 they need to be gapped to

.040 I think

luvmyhondas · Post by **luvmyhondas** » Tue Feb 22, 2011 11:10 pm

do you get fuel at the same place EVERY time?
are you by chance using 10% ethanol blended fuel?
wider tires?
carrying more weight/cargo?
oil consumption?
any aerodynamic changes?

eh2_Erik · Post by **eh2_Erik** » Wed Feb 23, 2011 4:37 am

Injectors? does it smell like gas?

ZenkiS14 · Post by **ZenkiS14** » Wed Feb 23, 2011 2:09 pm

luvmyhondas;256952 wrote:do you get fuel at the same place EVERY time?
are you by chance using 10% ethanol blended fuel?
wider tires?
carrying more weight/cargo?
oil consumption?
any aerodynamic changes?

No. I rarely ever get gas at teh same time every month lol
no. narrower tires
no weight
no oil consumption
aero change? lol no

How would it be my injector? No it doesnt smell like fuel at all.

Waffles · Post by **Waffles** » Wed Feb 23, 2011 2:38 pm

ZenkiS14;257059 wrote:How would it be my injector? No it doesnt smell like fuel at all.

if they are dirty one could be stuck open a little leaking gas constantly

opntrk86 · Post by **opntrk86** » Wed Feb 23, 2011 2:56 pm

stolle;256931 wrote:maybe a clogged catalytic converter?

+1 for my first guess

maybe the replacement O2 was not a quality part, I use denso or ngk only (I've seen a few hondas not like bosch sensors)

ZenkiS14 · Post by **ZenkiS14** » Thu Feb 24, 2011 3:08 pm

How do I check my injectors to see if they are functioning properly? I have heard that it does smell rich when people drive behind me now that I remember.