ok an updater, after oil change and put some additive or injection cleaner and a combined hway and city, mostly hway driving, ave speed is 120, sometimes going 130 to 140 kph and filling it up again at the automatic stop in the pump, i only manage to have a fuel mileage from 14 mpg (6 km/l) to 18mpg (8km/l) very small improvement.still not satisfied,next is try to replace air filter element with a k&n. will it help or just go with an ordinary brand like fram?any insights?
Is the air filter clean? Are you pulling any trouble codes? Perhaps the coolant temp sensor is needing replacement which will allow the engine to run overly rich. You don't smell any fuel around the car or engine bay do you?
Is the air filter clean? Are you pulling any trouble codes? Perhaps the coolant temp sensor is needing replacement which will allow the engine to run overly rich. You don't smell any fuel around the car or engine bay do you?
havent change the filter yet,just cleaned it tough. no trouble codes either. no fuel smell too on the engine or around the car.planning to replace air filter with a k & n,is it worth it?also have plans to deristrict the airbox and put some holes in it before the filter. anymore insights guys? thanks
A K&N replacement for the stock filter is not worth it. It flows only slightly better, but doesn't filter nearly as well as a paper filter - and if you over-oil it when cleaning it, you run a very real risk of ruining your MAF.
The stock airbox flows very well for a 4 cylinder; the same design (right down to the exact same filter) is used on several V6 Nissans. And even if there was a restriction in the intake, the ECU would still try to keep the air/fuel ratio appropriate.
niceguy may be on to something, if the coolant temp sensor is bad the ECU will always think the engine is cold - which will make it run really rich. If you have access to a decent scan tool you should be able to see what temp the ECU thinks the engine is at.
A K&N replacement for the stock filter is not worth it. It flows only slightly better, but doesn't filter nearly as well as a paper filter - and if you over-oil it when cleaning it, you run a very real risk of ruining your MAF.
The stock airbox flows very well for a 4 cylinder; the same design (right down to the exact same filter) is used on several V6 Nissans. And even if there was a restriction in the intake, the ECU would still try to keep the air/fuel ratio appropriate.
niceguy may be on to something, if the coolant temp sensor is bad the ECU will always think the engine is cold - which will make it run really rich. If you have access to a decent scan tool you should be able to see what temp the ECU thinks the engine is at.
thanks for the response bro. to recap, on my first full tank of fuel that is with new plugs installed, i only manged to have a 6km/liter of mileage all city driving. second tank with oil change and with combined city and highway driving, 7km/liter. third tank, mostly city driving again, 7.5km/liter. this will be my third tank full, have put stp injector cleaner and deristricted my airbox by removing two snorkels, the long one and short one.now, the airbox is with only one hole and i improvised a screen ont the hole to keep leaves and dirt from entering the box. reset the ecu by removing the negative cable on the battery together with the engine control fuse inside the cabin. noticed the engine breathe easier, dont have to step on hard to accelerate, and noticed it has more power. hope that its not just psychological though. but also noticed one thing, the auto trans upshifts too early. i felt that the engine's rpm is not yet ready for an upshift but the trans upshifts. and when i eas of the pedal while driving it also shifts leaving the engine lugging, so i have to step on it again for the trans to shift in its proper gear. i dont have an access to a scan, hope i did have. well, the temp gauge seems showing almost half in its scale and the engine warms by ok, though its beginning to get cold here in toronto. with regards to the airfilter, thanks for the advise bcoz i myself is having second thoughts regarding the kn. cost too much and, youre right regarding the air flow. what would be the best filter that doesnt costs too much?all i know is the fram brand.any suggestions?
Last edited by I AM LEGEND; 11-18-2012 at 01:13 PM.
Keep in mind the auto Altima is rated around 18/26 now which is pretty crummy...we get about 21 city in the '93 auto due to my wife's conservative driving habits though.
Keep in mind the auto Altima is rated around 18/26 now which is pretty crummy...we get about 21 city in the '93 auto due to my wife's conservative driving habits though.
ill be glad if i will manage 23mpg.yet to find out.
Still no luck, after putting stp fuel injector cleaner on a full tank of fuel, and driving the car until it fuel reserve lights went on, still its a 7km/liter (16mpg)all city driving. havent change the air filter though.and its starting to get colder here in toronto. might be seeing much lower mpg soon.
it didnt happen,lol. its just stayed at 7kms/liter.well, ill try to get a new filter soon. and something happened this morning. while i was driving i noticed that the car suddenly lost its normal power, as in its sluggish and i have to really step on it to put it up to speed or pass someone. it turned out that my battery was about to go. left me stocked in the carwash, so i got another battery and noticed instantly its back on its normal power,aint slow anymore. well having a bad battery is one of the culprit in having such a bad fuel economy, be posting updates regarding my quest for fuel efficiency.
well its my first time in using a fuel injector cleaner. way back when i was in the philippines, i was using acetone as a fuel enhancer on my bikes, have you guys heard about the use of acetone as a fuel enhancer or additive? not a drastic difference in fuel mileage but there is and i noticed that my throttle response was crisp and the emission doesnt smell unburned fuels. im on the last 1/4 of fuel in the tank, im just averaging 300km from the moment the fuel nozzle does auto stop when filling to the fuel light reserve light turns on. what do you think guys?
update: have been off the boards lately. have done mostly highway driving lately with an average speed of 110 kph. still only managed to get 8.5km per liter. the nprevious owner of the car also told me he hadnt changed the transmission oil in it since getting it brand new 17 years ago. could it be also a cause of too much fuel consumption? the car shifts at 2000rpms and even 1500 when i get easy on the pedal. but if i have to give it power in taking ramps, merging on the freeway or passing, it shifts 3000 -4000rpms.
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