hey everyone. i just bought my first honda. its a 96 civic ex coupe with a b16a2 swap in it. i always thought hondas are know for rlly good gas mileage, but i get horrible gas mileage for some reason. it has an 11.9 gallon tank. ill fill it up all the way, and i will only get 150 miles on a full tank. i try and drive as casually as i can and it just doesnt seem to make a diff. the only thing it has it a short ram intake. its a crappy pvc pipe(bought it like that), maybe thats it? idk but i rlly need help figuring this out because im VERY dissapointed. plz get back to me as soon as possible and help me haha

 

how does your car run? my plug wires were bad on my em1 and my mileage sucked. after I changed them it went way up..

 

Did you do a full tuneup? Do you drive like Paul Walker?

 

Mmmm :S
How is your temperature gauge? It should settle at mid temp after a few miles and be rock solid here after. A stuck open thermostat causes low or fluctuating operating temp for the engine -> ECU up regulates fuel injection.

Measure your lambda sensor (ohms) - look up values in a shop manual.

 

haha no i dont drivelike him. and no i havent. how much would a full tune up be?

 

and wat do u mean plug wires?
im a noob lmao

 

Cap,rotor,plugs wires.
OEM on everything and NGK on the plugs.

Do you have a Cel's?

 

they are the long black wires that are on top of the valve cover. remove them . keep track of where they go. and buy some new ones from an autoparts store.also change spark plugs while your at it. gas mileage will be way better

 

i have similar set up... 99 dx with b16a2 (stock ECU) with CEL for secondary O2..... im getting 30mpg on mine. mostly freeway .......u might want to check the usual spark plug/wires/dizzy rotor and stuff... also change PCV valve..... fuel/air filter......and check if your gas cap still holds pressure.....if you have time go get ur injectors serviced.... also changing your O2 sensors might help too...mayb ur clutch is totally out?



.check your alignment too.....i used to have a b20 and my alignment was really wacked out(toe out) so i was getting 19mpg... after i got an alignment... i got 25 easy......

if nothing works.. bring to mechanic to run standard tests .....some people say cleaning the sensors on ur ITM and TB helps.... fix all CEL's.....


Tips: during first start up. dont let car warm up... drive it right away....

 

All good advice. Also do a valve adjustment, make sure the timing belt is installed correctly (I'd just put a new one in if you just got the car) and make sure ignition timing is set to spec. VTEC kills gas mileage so try to stay out of it if you are going for good mileage.

I've got a 98 hatch with a B18C that gets 35 mpg highway 30 mpg mixed with a CEL for the secondary O2 and one for EVAP purge solenoid. Sounds like you def have a problem, hope it's a simple fix.

 

it aint that much bro but if i were u i would change the oil and get new plugs and wires and if that dont help then we can get into more tech reasons for ur shitty milage

 

dam thats pretty good for a b18c with CEL..... is it a CX model?

 

Man i have the same problem i think i need new wires on my car but you should do a full tune up on your car and then go from there

 

is your check engine light on? 150 miles to a tank is horrible. im getting over 200 to a tank with an obd1 converted b16 with a cel and a restricted exhaust.

also where do you shift/cruise on the highway. it took some time getting used to not being able to do 70-80 on the highway like i was able to do in my d-series and still get mid 30s, and ive learned that with the short geared trans, i can shift well before 3k and still stick with the flow of traffic. im getting roughly 25mpg. also, are you running 91+ octane?

 

Na it's a DX, I just stay out of VTEC and keep the shift points low. Average speed is 65-70 mph. Maybe I'm just lucky.

 

i tryed shifting at like 3-4k for a whole tank and still got like 150-160 miles. im gonna get new plugs, plug wires. and i guess have my dads mechanic look at it. i just changed the oil so thats good. note-im 17 and this is my first car. but i still dont drive like an ******* like any 17 y.o. would. im just tyring to figure out this problem cuz its REALLLYYY pissing me off haha
thnx for the help. when i get everything checked out ill tell you guys

 

Do you have a check engine light? if so, that's a good place to start!

 

^^ check this! since i see you basically ignored it.

 

Never EVER EVER EVER EVER EVER EVER use the ohms function to test an o2 sensor!! You use the VOLT function!! Using the 'ohms' function on a multimeter would run a current through the o2 sensor, potentially destroying it. O2 sensors make a minute amount of electricity and to test their function, technically the cheapest easiest way is to use a volt meter (voltage function on multimeter) and run one probe to the body of the sensor and another probe to a wire on the harness.. Keep probing the harness until you get a reading. I test o2 sensors with a butane torch but on civics (especially those with the maniverter) you can easily test the sensor while the car is running since the sensor is right there in your face when you pop the hood. Anyway when you get the readings from the volt meter, what you're looking for is to see how quickly the readings change and whether they lag or tend to keep their readings despite a change in the exhaust.

For simplicity sake:
http://www.youtube.com/watch?v=vdn4Dk5PSwc
http://www.youtube.com/watch?v=ItnKP-XKaZo

most o2 sensors until very recently were "narrow band" and so really should be one wire but the reason they have more than one wire on the harness is because of the heater. O2 sensors use the body of the exhaust manifold as a ground for the SIGNAL of the o2 sensor. never forget this especially when diagnosing issues with an o2 sensor since a bad body ground will have a much more profound effect than any weak/old sensor could have.