1992 Civic CX Hatch 133xxx miles (1.5ltr sohc non-vtec)

I bought this car 3 weeks ago. within the first week i changed the following:
dizzy cap/rotor
Tranny Fluid
Engine Oil
Spark Plugs (ngk's)

I also ran a fuel system cleaner
put new tires on it and filled to 35 psi (cold temp)

removed the stock air box and replaced the TINY stock 'air hose arm' with a much bigger one from a d16y8
put cone filter on the end of it, aka- home-made shortram intake.

(new fuel filter will be installed asap and alignment of the car seems to be fine)

because this is my dd and only has 70hrspwr i'm primarily concerned with pushing the mpg to the limit.

on my last tank of gas i only got 30mpg (175 miles of highway and 80 city closely estimated) Highway driving was between 75-85 mph. I read in a post where NOFX listed a table that said my car should get 42/48ish.

Should i check for a fuel leak? could using fuel system cleaner give me worse gas milage on the tank that it was pured in? would driving 85mph cause such low fuel efficiency? what else can I do to get better gas milage? are my hopes of 45mpg too high? Im interested in hearing suggestions, most of the other 'gas' threads ended up arguing over spelling or rambling in some other direction.

 

I've noticed huge difference in my hatch driving either 70 mph (the posted speed limit in Florida) or going 85 (just keeping with traffic in the fast lane). Just for laughs, get in the slow lane and go 70, I think you'll notice a huge difference.

 

you've got a good start. you didn't say if it was a stick or auto. that can matter. also how are you calculating mileage?

i always want to know the condition of the engine. total mileage isn't always the best indicator. i've seen 280k mi engines look and run way better than the same type engine with 80k mi.

some good checks are ignition timing and compression. if you have the means to do either, you should. remember brakes too. if you have a caliper sticking you're hurting your mileage and risking more than your bank account. get them checked if you havn't already. of course don't make the simple mistake of keeping extra crap in your trunk or backseat. the weight adds up. and what's your engine rpm at 75-80 mph? i am guessing the gearing is pretty low in a CX.

the best way to check for fuel leaks is with your nose.. if you don't smell it, don't worry much about it.

 

it's a standard. no real clue on rpm because it currently doesn't have a tac.

i calculated mileage by getting a full tank, resetting my trip odo, driving to E, and then filling it all the way up again. took the milage from the trip odo divided by the number of gallons that i had just put in it.

the only thing i keep in the trunk/backseats is an extra pair of shoes. no clutter or extra anything like some people. also i've never smelled any gas in or around the car

initially i thought the motor was fantastic condition- it's clean, runs super smooth, and starts very quickly. it's the 4th honda i've owned and i think it runs just as well as any of them but- its not getting north of 30mpg (seemingly)

 

replace you PCV valve, that should help

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95vxtealhatch &raquo;</TD></TR><TR><TD CLASS="quote">replace you PCV valve, that should help</TD></TR></TABLE>

ok, there really is no reason not to do that considering it's only like a dollar. but i never really understood how they work/help. lol. i mean, obviously they are part of the vaccume system but that's all i know. thanks for the advice man

 

The PCV is important!

It shoots blowby gases from the crankcase through the valve back into the intake manifold to be burned again in the engine. It's like a vulture for your inefficient gas consumer.

It consists of a hose running from your valve cover to the intake manifold and a fresh air hose running from the intake bot to the valve cover.

 

I have a 1996 cx automatic and when I got the car, it was getting 24 mpg mostly city. I got it up to 29mpg city by changing the spark plugs, air filter, PCV, new tires and alignment, fresh oil, new coolant, new tranny oil, new plug wires, and I "sea-foamed" the hell out of it.

 

i've heard that modifying the 'charcoal can' by basically gutting it or replacing it with an empty catch can can also improve mpg drastically. has anyone done this or know for sure?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aludew5 &raquo;</TD></TR><TR><TD CLASS="quote">i've heard that modifying the 'charcoal can' by basically gutting it or replacing it with an empty catch can can also improve mpg drastically. has anyone done this or know for sure? </TD></TR></TABLE>
i removed the complete system on my B16 and i get 26mpg around town and like 30 miles of freeway driving. If it s cold it will drop to about 24mpg city. I have a completely street tuned P28 though so my A/F ratios are dead on and runs niiiice.

 

check your oxygen sensor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93egSLEEPER &raquo;</TD></TR><TR><TD CLASS="quote">
i removed the complete system on my B16 and i get 26mpg around town and like 30 miles of freeway driving. If it s cold it will drop to about 24mpg city. I have a completely street tuned P28 though so my A/F ratios are dead on and runs niiiice.</TD></TR></TABLE>

how did you remove it? where did you re-route the vaccume lines? or did you?

 

are you sure you aren't driving with your left foot on the brake when you aren't shifting

 

I have a 93 CX with a CX trans and a DX Engine I have found that if I downshift my mileage goes to ****! There is also a huge difference in my driving styles. If I drive like a granny I get 42-44 MPG if I drive normal I get about 30-32 MPG In town that is. On the highway I get about 28 MPG if I go 75-80 MPH and 33-35 MPG if I go 65-70 MPH.
Later, Drew

 

On your next oil change switch to synthetic. You didn't say how thick of oil you used when you changed. Be sure to use 5W30 if that is recommended for that engine. Don't use thicker oil than recommended unless it uses a lot.

Temperature also is a huge factor with the 94 & 99 EJ's in our family. Jack rabbit starts will kill gas mileage especially with VTEC engines. I'd say there is a bigger difference between 75 & 85 than between 65 & 75 mph. At about 65 wind resistance becomes more than ground resistance. It quickly becomes a bigger & bigger factor.

Head wind or side wind is also a huge factor.

I've been putting my gas mileage in a spreadsheet for years so I can compare the same month from different years and year to year. Several tanks will give you a better picture. There is also the problem of getting the tank filled to exactly the same level. My 99 is hard to get full because it keeps shutting the flow off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cool_junk &raquo;</TD></TR><TR><TD CLASS="quote">I have a 93 CX with a CX trans and a DX Engine I have found that if I downshift my mileage goes to ****! There is also a huge difference in my driving styles. If I drive like a granny I get 42-44 MPG if I drive normal I get about 30-32 MPG In town that is. On the highway I get about 28 MPG if I go 75-80 MPH and 33-35 MPG if I go 65-70 MPH.
Later, Drew</TD></TR></TABLE>

thanks man. i just can't figure out how my friend's 92 si can be driven harder with more weight loaded in and get 10 mpg more than me. lol. i definately downshift all the time. i will try to stop.