Crappy Gas Mileage

D15, D16, D17 and Mini-Me swaps
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Crappy Gas Mileage

By LilSquirtEX
- Sat Aug 21, 2010 2:59 pm #209923

I have a D16Y8 in my Civic EX with 38,000 miles on it. I just bought the car a little over a month ago and noticed it was getting between 19 - 23 mpg. Horrible I know. Does anybody have any ideas on how to improve gas mileage. So far I have replaced; Spark Plugs, Dizzy cap and rotor, Fuel filter, stock air intake with Cold air intake, header, belts, tires are new, cleaned throttle body, adjusted the valves, and did a seafoam treatment. Now I'm up to 27mpg, but I know I can get way better. :x Any tips will be appreciated.
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By TrailerTrash
- Sat Aug 21, 2010 3:13 pm #209924 make sure your tires are properly inflated and keep your foot out of it. i have a jdm d15b and a dx tranny that gets me 42mpg. i just put put the hell out of it never jumping on the gas and i shift at 1,600rpms everytime. you could get bad milage in a smart car if you don't know how to take it easy on the gas pedal.

if you shift below 2,000rpms and dont try to get up to speed quickly your gas milage will skyrocket
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By teal_dx
- Sat Aug 21, 2010 3:58 pm #209926 - get the alignment checked
- check the timing with a timing gun
- replace the o2 sensor (they can begin to go bad but not bad enough to throw a check engine light)
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By blk92hb
- Sat Aug 21, 2010 7:21 pm #209955 change it from an auto to a manual and put on a catback or just come over to the house and chill :lol: j/k but still put it up in the air and check to see if the pads are not rubbing the rotors. if so it could be a sticking caliper. also remove the caliper and see if the wheel rotate freely if not it could be a bad wheel bearing.

By Method
- Sat Aug 21, 2010 8:32 pm #209967
TrailerTrash wrote:make sure your tires are properly inflated and keep your foot out of it. i have a jdm d15b and a dx tranny that gets me 42mpg. i just put put the hell out of it never jumping on the gas and i shift at 1,600rpms everytime. you could get bad milage in a smart car if you don't know how to take it easy on the gas pedal.

if you shift below 2,000rpms and dont try to get up to speed quickly your gas milage will skyrocket


really?? not even automatic vechicles shift below 2000. who told you to do this?
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By LilSquirtEX
- Mon Aug 23, 2010 1:15 am #210096 I checked the timing. I forgot to put that on there. It was off by quite a bit, but I got that fixed. I have an alignment already scheduled in the near future. I totally spaced on the O2 sensor. Thanks TealDX. I did replace my ebay air filter on my cold air intake with a Spectre air filter yesterday. Now I don't know if my mpg's today were a fluke or what but I got 36 mpg highway. :woot:
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By TrailerTrash
- Mon Aug 23, 2010 3:47 am #210114
Method wrote:
TrailerTrash wrote:make sure your tires are properly inflated and keep your foot out of it. i have a jdm d15b and a dx tranny that gets me 42mpg. i just put put the hell out of it never jumping on the gas and i shift at 1,600rpms everytime. you could get bad milage in a smart car if you don't know how to take it easy on the gas pedal.

if you shift below 2,000rpms and dont try to get up to speed quickly your gas milage will skyrocket


really?? not even automatic vechicles shift below 2000. who told you to do this?


no one told me to thats just how i drive. slow as shit. im never in a hurry to get anywhere.
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By Classiccarsrule85
- Mon Aug 23, 2010 5:03 am #210127
TrailerTrash wrote:
Method wrote:
TrailerTrash wrote:make sure your tires are properly inflated and keep your foot out of it. i have a jdm d15b and a dx tranny that gets me 42mpg. i just put put the hell out of it never jumping on the gas and i shift at 1,600rpms everytime. you could get bad milage in a smart car if you don't know how to take it easy on the gas pedal.

if you shift below 2,000rpms and dont try to get up to speed quickly your gas milage will skyrocket


really?? not even automatic vechicles shift below 2000. who told you to do this?


no one told me to thats just how i drive. slow as shit. im never in a hurry to get anywhere.



I had a pretty original '84 bmw 318i 4cyl bmw m10 engine and well they get there gas mileage as well there was a sticker on it saying shift after reaching 3-3500 rpm as you dont get much more horse power after that and i mean without vtec and all that other stuff thats correct i mean with vtec its built for you to accelerate easier on the highway if you will......or get up to speed faster (more or less highway) you can decrease you fuel consumption if you dont hit vtec until you need them ponies....
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By suspendedHatch
- Wed Aug 25, 2010 6:22 pm #210532 Do a valve adjustment.

If the tires are shit they'll absolutely kill the mileage no matter what you do.

Make sure your wheel aspect ratio is close to stock. It will throw off your readings.

Lubricate your caliper pins with high temp grease.

Change tranny fluid.

I get 36 mpg out of my 97 GSR shifting at 3k. More important than when you shift is how much space you leave in front of you. Keep a few car lengths of open space in front of you so you don't have to use the brakes as much. I drive off peak hours. Luckily the graveyard shift allows for that. And when I see a stop light from a distance I time it so I keep the car rolling even if it's a very low speed. Leaving from a full stop just dumps gas.

If I whale on the GSR it will drop 6 mpg easily. That was not the case when I had a D series. I would punch it getting on the freeway and I never noticed much change in fuel economy.
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By blk92hb
- Thu Aug 26, 2010 12:16 am #210587 its an automatic trans and we already did a valve adjustment. i honestly dont know what else to do to :? it he is around 29-36 mpg with an average of 30 mpg
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By LilSquirtEX
- Fri Aug 27, 2010 2:21 am #210758 Quick update, so far I have been averaging 32 mpg. The most recent thing I did was run Lucas Fuel Injector Cleaner and Fuel Stabalizer through it. I still need to replace 02 sensors, and perform an alignment. Slowly getting to my 40+ mpg. :woot:
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By LilSquirtEX
- Fri Aug 27, 2010 2:24 am #210760 It has new tires, stock at that. Tranny has over 200,000 miles on it, so I am in the market for a tranny. possibly a 5 speed swap.
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By Digs
- Sun Aug 29, 2010 3:53 pm #211097 hey guys, i didnt want to start a whole new thread for a similar issue, so i havent been on here in a long time, i sold my sedan that i put up on here and i bought another one, it also has a 1500 carb d series like my previous one but im getting 19mpg, which i think is a bit low, im running power steering and it has a/c, stock 13" steelies, im driving in traffic, on highways, and not in traffic and i still get 19mpg no matter what, i havent done anything like a fuel injector cleaner, and im shifting between 2000 and 3000, what do you guys suggest i do
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